Effects of vancomycin,daptomycin, fosfomycin,tigecycline, and ceftriaxone on Staphylococcus epidermidis biofilms

Infection of medical implanted material is associated with considerable morbidity and costs. In the following work, we investigated the effects of vancomycin, daptomycin, fosfomycin, tigecycline, and ceftriaxone on biofilms formed by Staphylococcus epidermidis isolates causative for implant infection and catheter‐associated bacteremia. Biofilms were studied using the static microtiter plate model and incubated with the antibiotics increasing the concentration from 1× to 128× the minimal inhibitory concentration (MIC) of the respective isolate tested. To quantify the reduction of the biomass, the optical density ratio (ODr) of stained biofilms and the number of growing bacteria were determined. Incubation of the staphylococcal biofilms with the antibiotics decreased the biofilm ODr (at baseline = 1) for ceftriaxone (0.83 ± 0.48) but minimally only for fosfomycin (0.96 ± 0.64), daptomycin (1.05 ± 0.59), tigecycline (1.18 ± 0.66), and vancomycin (0.98 ± 0.44) at exceedingly high concentrations of 128 × MIC. The significant reduction of the bacterial growth was not achieved for all antibiotics, not even at the highest concentrations tested. Using higher doses of the antibiotics may be of some value in the treatment of biofilm‐associated infections, although effects are seen only at clinically unachievable doses. However, to eradicate the staphylococcal biofilm, additional measures like debridement and/or removal of the implant are needed. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1361–1365, 2009     

T-cell phenotypic and functional changes associated with social subordination and gene polymorphisms in the serotonin reuptake transporter in female rhesus monkeys

Increased vulnerability to psychosocial stressors likely predisposes individuals to decreased immune function and inability to control pathogens. While many factors influence the susceptibility to psychosocial stress, genetic polymorphisms may modify individual reactivity to environmental stressors. The present study evaluated how immune function was altered by the interaction of in polymorphisms in the gene that encodes the serotonin reuptake transporter (5HTT) and the psychosocial stress imposed by social subordination in adult female rhesus monkeys. Subjects were dominant and subordinate females that carried both alleles of the long promoter variant (l/l) of the 5HTT gene, and dominant and subordinate that had at least one allele for the short promoter length variant (l/s or s/s, s-variant). Plasma cortisol was higher in subordinate females in response to a social separation paradigm, confirming their increased reactivity to psychosocial stressors. Subordinate females exhibited increased T-cell activation and proliferation regardless of genotype. Despite these higher levels of T-cell proliferation and activation, subordinate females showed significantly lower frequency of T-cells. This latter finding may be due to an increased susceptibility to cell death, as indicated by higher levels of annexin-V+ CD4+ and CD8+ T-cells in s-variant subordinate compared to dominant females. These findings indicate that subordinate rhesus monkeys with the s-variant 5HTT genotype exhibit decreased T-cell numbers perhaps compromising their ability to mount an immune response to pathogens. These data underscore the importance for considering gene polymorphisms that influence emotional reactivity to better understand susceptibility to disease.     

High K+-induced contraction requires depolarization-induced Ca2+ release from internal stores in rat gut smooth muscle

Aim:

Depolarization-induced contraction of smooth muscle is thought to be mediated by Ca²⁺ influx through voltage-gated L-type Ca²⁺ channels. We describe a novel contraction mechanism that is independent of Ca²⁺ entry.

Methods:

Pharmacological experiments were carried out on isolated rat gut longitudinal smooth muscle preparations, measuring isometric contraction strength upon high K⁺-induced depolarization.

Results:

Treatment with verapamil, which presumably leads to a conformational change in the channel, completely abolished K⁺-induced contraction, while residual contraction still occurred when Ca²⁺ entry was blocked with Cd²⁺. These results were further confirmed by measuring intracellular Ca²⁺ transients using Fura-2. Co-application of Cd²⁺ and the ryanodine receptor blocker DHBP further reduced contraction, albeit incompletely. Additional blockage of either phospholipase C (U 73122) or inositol 1,4,5-trisphophate (IP₃) receptors (2-APB) abolished most contractions, while sole application of these blockers and Cd²⁺ (without parallel ryanodine receptor manipulation) also resulted in incomplete contraction block.

Conclusion:

We conclude that there are parallel mechanisms of depolarization-induced smooth muscle contraction via (a) Ca²⁺ entry and (b) Ca²⁺ entry-independent, depolarization-induced Ca²⁺-release through ryanodine receptors and IP₃, with the latter being dependent on phospholipase C activation.     

Excision of large cystic ovarian tumors: combining minimal invasive surgery techniques and cancer surgery--the best of both worlds

Background/Purpose

Cystic ovarian lesions can be massive, and preoperative evaluations can often not distinguish benign from malignant tumors. Up to 57% of malignant ovarian tumors have a cystic component. We present an approach to these neoplasms that adheres to oncologic principles using minimally invasive techniques.

Methods

A 5-cm Pfannensteil incision is performed followed by peritoneal washings. The mass is identified and dried. Dermabond (Ethicon, Johnson & Johnson, New Jersey) is applied to an area of the capsule (measuring 3 × 3 cm) and to a sterile plastic ultrasound bag. The bag is then applied directly to the exposed capsule. BioGlue (Cyrolife Inc, Kennesaw, GA) is then injected into and around the bag/mass interface and allowed to solidify. A veress needle decompresses the cyst, and the ovary is delivered out of the peritoneal cavity for either cystectomy or an oophorectomy. Routine surveillance of the omentum, lymph nodes, contralateral ovary, and peritoneal surface is then performed.

Results

Nine female patients (mean age, 14.1 ± 2 years) were treated. All had normal α-fetoprotein and human chorionic gonadotropin. Computed tomographic scans demonstrated cystic lesions ranging from 8.9 to 27 cm in diameter (17.1 ± 2.6 cm²). Operative procedures were: 4 salpingooophorectomies and 5 unilateral oophorectomies. In a single case, the contralateral ovary had a suspicious lesion, which was biopsied. No tumors spills occurred. The pathology included 2 simple cysts, 3 serous cyst adenomas, 3 mature cystic teratomas, and 1 immature teratoma with grade 2 to 3 immature elements. Peritoneal washings were negative. All patients were discharged within 48 hours and are well 15 months to 3.1 years postoperatively.

Conclusions

The containment of the ovarian cyst with the application of surgical adhesives and a plastic sleeve offers a significant advancement in our ability to safely treat these lesions. This approach markedly reduces the length of the surgical incision while insuring the prevention of peritoneal contamination with cystic fluid.     

Interacting genes in lithium prophylaxis: Preliminary results of an exploratory analysis on the role of DGKH and NR1D1 gene polymorphisms in 199 Sardinian bipolar patients

Lithium represents the first-choice and most effective drug in the treatment of bipolar disorder (BD). While its mechanism of action is far from being totally understood, a large amount of evidence pointed to a role of second messengers mediated pathways and elements of the circadian system in modulating its mood stabilizing effect. In the present paper, we tested the possible association and interaction effect of the nuclear receptor subfamily 1, group D, member 1 (NR1D1) gene and the Diacylglycerol kinase eta (DGKH) gene with the therapeutic response to lithium prophylaxis. Single nucleotide polymorphisms (SNPs) rs12941497 and rs939347 at NR1D1 gene and SNPs rs9315885, rs1012053 and rs1170191 at DGKH gene were genotyped in a sample of 199 Sardinian BD patients characterized for the response to lithium therapy. Genotype and allele frequency distributions did not differ significantly between groups of patients Full Responders and partial/not responders to lithium prophylaxis. Moreover, no significant differences were identified between groups of patients when divided considering the improvement in symptoms after lithium treatment. The interaction analysis did not show a significant effect on these outcomes. While negative, our findings do not exclude an involvement of DGKH and NR1D1 in lithium prophylaxis. Moreover, the lack of statistic interaction might not necessarily correspond to a lack of biologic interaction between the genes studied.     

Effects of depth and chest volume on cardiac function during breath-hold diving

Cardiac response to breath-hold diving in human beings is primarily characterized by the reduction of both heart rate and stroke volume. By underwater Doppler-echocardiography we observed a “restrictive/constrictive” left ventricular filling pattern compatible with the idea of chest squeeze and heart compression during diving. We hypothesized that underwater re-expansion of the chest would release heart constriction and normalize cardiac function. To this aim, 10 healthy male subjects (age 34.2 ± 10.4) were evaluated by Doppler-echocardiography during breath-hold immersion at a depth of 10 m, before and after a single maximal inspiration from a SCUBA device. During the same session, all subjects were also studied at surface (full-body immersion) and at 5-m depth in order to better characterize the relationship of echo-Doppler pattern with depth. In comparison to surface immersion, 5-m deep diving was sufficient to reduce cardiac output (P = 0.042) and increase transmitral E-peak velocity (P < 0.001). These changes remained unaltered at a 10-m depth. Chest expansion at 10 m decreased left ventricular end-systolic volume (P = 0.024) and increased left ventricular stroke volume (P = 0.024). In addition, it decreased transmitral E-peak velocity (P = 0.012) and increased deceleration time of E-peak (P = 0.021). In conclusion the diving response, already evident during shallow diving (5 m) did not progress during deeper dives (10 m). The rapid improvement in systolic and diastolic function observed after lung volume expansion is congruous with the idea of a constrictive effect on the heart exerted by chest squeeze.     

Immunohistochemical localization of Clara cell secretory proteins (CC10-CC26) and Annexin-1 protein in rat major salivary glands

The oral cavity is continuously bathed by saliva secreted by the major and minor salivary glands. Saliva is the first biological medium to confront external materials that are taken into the body as part of food or drink or inhaled volatile substances, and it contributes to the first line of oral defence. In humans, it has been shown that sputum and a variety of biological fluids contain Clara cell secretory proteins (CC10–CC26). Various studies of the respiratory apparatus have suggested their protective effect against inflammatory response and oxidative stress. Recently, CC10 deficiency has been related to the protein Annexin‐1 (ANXA1), which has immunomodulatory and anti‐inflammatory properties. Considering the defensive role of both Clara cell secretory proteins and ANXA1 in the respiratory apparatus, and the importance of salivary gland secretion in the first line of oral defence, we decided to evaluate the expression of CC10, CC26 and ANXA1 proteins in rat major salivary glands using immunohistochemistry. CC10 expression was found only in the ductal component of the sublingual gland. Parotid and submandibular glands consistently lacked CC10 immunoreactivity. In the parotid gland, both acinar and ductal cells were always CC26‐negative, whereas in the submandibular gland, immunostaining was localized in the ductal component and in the periodic acid Schiff (PAS)‐positive area. In the sublingual gland, ductal cells were always positive. Acinar cells were not immunostained at all. ANXA1 was expressed in ductal cells in all three major glands. In parotid and sublingual glands, acinar cells were negative. In submandibular glands, immunostaining was present in the mucous PAS‐positive portion, whereas serous acinar cells were consistently negative. The existence of some CC10‐CC26–ANXA1‐positive cells in rat salivary glandular tissue is an interesting preliminary finding which could support the hypothesis, suggested for airway tissue, that these proteins have a defensive and protective role. Protein expression heterogeneity in the different portions of the glands could be an important clue in further investigations of their role.