Association of CAPN1 316, CAPN1 4751 and TG5 markers with bovine meat quality traits in Mexico.

We examined allele and genotype frequencies for the molecular markers CAPN1 316, CAPN1 4751 and TG5, and determined whether they are associated with beef quality traits in Mexican cattle. One hundred and twenty-four longissimus dorsi muscle samples were collected from cattle from north, central and southern Mexico. CAPN1 316 and CAPN1 4751 frequencies were determined using the allelic discrimination assay and the TG5 marker was typed by PCR-RFLP. Meat quality traits included intramuscular fat content (IMF) and tenderness determined by Warner-Bratzler shear force (WBSF) at 24 h postmortem. The association test was made using a mixed model, including genotypes, genetic group, and sampling location as fixed effects. Least squares means and significant interactions were compared using least significant differences based on the mixed procedure. CAPN1 316 CC was found at a low frequency (0.03) and has been reported as a favorable genotype associated with tenderness meat. Genotype frequencies for CAPN1 4751 were similar in favorable (CC) and unfavorable (TT) genotypes (0.26 and 0.28, respectively). The TG5 CC genotype had a frequency of 0.73, while the TT genotype frequency was 0.01. The means for WBSF and IMF were 4.08 ± 1.35 kg and 5.23 ± 2.14%, respectively. Sampling site and the CAPN1 316 genotypes significantly affected WBSF (P < 0.05). Samples collected from Hermosillo, Sonora, had the lowest WBSF (P < 0.05), while those collected in Veracruz were toughest (WBSF = 5.267 kg). The effect of GG and TG5 genotypes on IMF was significant (P < 0.05). CAPN1 316 and TG5 markers were found to be significantly associated with beef quality traits and thus will be useful for Mexican beef characterization.

Melanoma circulating tumor cells: Benefits and challenges required for clinical application.

The implementation of novel therapeutic interventions has improved the survival rates of melanoma patients with metastatic disease. Nonetheless, only 33% of treated cases exhibit long term responses. Circulating tumor cell (CTC) measurements are currently of clinical value in breast, prostate and colorectal cancers. However, the clinical utility of melanoma CTCs (MelCTCs) is still unclear due to challenges that appear intrinsic to MelCTCs (i.e. rarity, heterogeneity) and a lack of standardization in their isolation, across research laboratories. Here, we review the latest developments, pinpoint the challenges in MelCTC isolation and address their potential role in melanoma management.

Salvage therapy for multidrug-resistant tuberculosis.

Treatment of multidrug-resistant tuberculosis (MDR-TB), defined as Mycobacterium tuberculosis resistant to both isoniazid and rifampicin, is challenging under the best of circumstances, and particularly in resource-limited settings. For patients who remain persistently sputum-culture-positive despite therapy with second-line TB drugs, treatment options are limited, especially if disease is too advanced for resective surgery. Salvage therapy refers to the design of a regimen combining new and previously used drugs in a final effort to attain sputum conversion before declaring treatment to have failed. We retrospectively evaluated the outcomes of salvage therapy in 213 Peruvian patients. Salvage regimens included a median of two new drugs (range 1-6) and nine (range 5-13) total (new plus previously used) drugs. The most frequently used new drug was moxifloxacin, followed by capreomycin, amoxicillin-clavulanate, kanamycin and clarithromycin. Culture conversion occurred in 65 (30.5%) patients. Salvage regimens that included moxifloxacin were significantly more likely to be followed by culture conversion (OR 2.2; p 0.02). Later-generation fluoroquinolones such as moxifloxacin should be used in salvage therapy but also in the initial treatment of MDR-TB, if the best clinical strategy is to use the most effective drugs when the patient has the best chance for cure. New TB drugs are most likely to be initially used in salvage patients, in conditions similar to those described here. Close bacteriological monitoring of these patients will be essential, as useful information about the best way to use these new drugs can be gained from analysis of salvage therapy cohorts.

Toxoplasma gondii pneumonia in patients with the acquired immunodeficiency syndrome: diagnosis by bronchoalveolar lavage.

We describe the cases of two individuals with advanced AIDS who sought treatment for rapidly progressive respiratory failure due to T gondii pneumonia. The first patient responded to specific therapy after an early diagnosis but died 2 months later of bacterial sepsis. In the second case, the diagnosis was made at autopsy. This led to a meticulous retrospective review of the original slides of material obtained from BAL. T gondii tachyzoites not previously identified during the initial analysis of the slides were seen on both GIE and PAP stains. Neither of our severely immunocompromised patients had evidence of central nervous system involvement. Even though we cannot exclude dissemination to other organs, a progressive pneumonitis mimicking a classic P carinii infection was the primary presentation. Trophozoites were identified by BAL in both cases, underscoring the diagnostic potential of this minimally invasive procedure.

Fatty acid and prostaglandin composition of left ventricular myocardium from dexamethasone-treated dogs with severe low output syndrome (LOS).

The effects of dexamethasone (DEX) administration on the left ventricular myocardial content of fatty acids and prostaglandins E1, E2 and F2alpha were studied. Following a complete right and left cardiac catheterization, either DEX (8 mg/kg) or an equivalent volume of its vehicle was given intravenously 30 minutes prior to low output syndrome (LOS induction, and supplemental doses of DEX (4 mg/kg) or vehicle administered at 15 and 75 minutes post-LOS induction. Low output syndrome was induced by intravenous administration of a myocardial depressor protein (MDP) which has been isolated from the venom of the Western diamondback rattlesnake, Crotalus atrox. Neither DEX nor its vehicle had a significant effect during the entire experiment, that is, in the normal or low cardiac output state in most of the hemodynamic parameters investigated. The three hour mortality rate for the DEX-treated animals was 22% (n=10) while that of the control group was 41% (n=26) indicating that the beneficial effects of this corticosteroid are not really apparent from hemodynamic evaluation alone. Since DEX only had a significant post-LOS induction effect in maintaining a lower left ventricular end-diastolic and pulmonary capillary wedge pressures, a higher arterio-venous oxygen saturation difference, and a more efficient contractile state of myocardial fibers (Vmax), an indirect correlation to coronary arterial blood flow at the subcellular level was sought. To this effect, prostaglandins and specific lipid classes of left ventricular myocardium (LVM) from control and LOS animals receiving either vehicle or DEX were analyzed. Low output state induction alone raised myocardial PG levels above those of sham-catheterized animals; on the other hand, dexamethasone induced a significant decrease in the three prostaglandins studied when administered to control (no LOS) animals. In the presence of LOS, however, dexamethasone overrode in part the increase in PGE1 and PGE2 brought about by LOS while in the case of PGF2alpha the LOS effect was totally prevented and its concentration was not significantly higher than in control animals receiving dexamathasone. LOS induction led to an increase in myristic and arachidonic acids and a decrease in palmitic and linolenic acids. Dexamethasone administration to control animals increased the concentration of stearic acid above all the other groups but decreased the concentration of linolenic acid when compared to DEX-treated animals with LOS or sham-catheterized animals. There were no significant differences in the total myocardial lipid among the four groups of animals studied. It is suggested that the potentially beneficial effects of corticosteroid administration to animals with low output syndrome are related to their effects on fatty acid and prostaglandin content of myocardium.

Comparative biochemistry and pharmacology of salivary gland secretions. III. Chromatographic isolation of a myocardial depressor protein (MDP) from the venom of Crotalus atrox.

A protein has been isolated from the venom of the western diamondback rattlesnake (Crotalus atrox) which induces acute myocardial depression when administered to experimental animals. Purification was achieved by gel filtration on Sephadex G-100, DEAE- and CM-cellulose ion-exchange chromatography, ultra-filtration, and adsorption chromatography on hydroxyapatite. Amino acid analysis of the highly purified protein indicated N-terminal isoleucine and C-terminal tyrosine residues, and the absence of free sulfhydryl groups. Rabbits were immunized against the myocardial depressor protein (MDP) and a highly specific antiserum prepared which made it possible to study other snake venoms for the presence or absence of MDP. All of the North American Crotalid species of snakes contain MDP in varying degrees of concentration, but none of the Asiatic snake venoms tested reacted with the antiserum to the myocardial depressor protein. Intravenous administration of MDP to experimental animals (dogs, cats) produces an immediate and profound decrease in the cardiac output, the left ventricular systolic and mean pressures, the velocity of shortening of the contractile element, the systemic arterial pressure and an elevation in the left ventricular end-diastolic and pulmonary wedge pressures. These hemodynamic changes indicate that MDP administration induces an acute myocardial failure which is does dependent. The potential use of this protein for the reproducible causation of left ventricular failure, obviating the need for the more commonly used surgical ligation of the coronary arteries, warrants a full investigation into its structure, active site and its mechanism of action on the myocardial cell.

Hemodynamic effects of slow and rapid defibrination with defibrizyme, the thrombin-like enzyme from venom of the timber rattlesnake.

The hemodynamic response to slow and rapid defibrination was sutdied in anesthetized beagle dogs, with the following results: 1. Slow defibrination was a benign procedure that had little or no effect on the hemodynamic variables studied. 2. Rapid defibrination induced statistically significant decreases in cardiac output, stroke volume, and mean aortic arterial pressure. 3. Bradycardia, a drop in mean left v"ntricular pressure, cardiac and minute work indices, an increase in pulmonary artery pressure, and a drastic rise in pulmonary and systemic vascular resistances were also observed. Although physiologically apparent, these changes were not statistically significantly different from control levels. 4. Pulmonary capillary wedge pressure, left ventricular end-disatolic pressure, arterial pH, and blood gases were not altered by rapid defibrination. 5. In view of the similarities between the hemodynamic changes observed after rapid defibrination and acute myocardial ischemia, the role of decreasing fibrinogen concentrations and blood viscosity in aucte myocardial infarction and the sudden death syndrome is questioned.