Heterogeneity in the effect of different ixodid tick species on human natural killer cell activity

Tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. Furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. We report that salivary gland extracts (SGE) derived from Dermacentor reticulatus adult ticks induce a decrease in the natural killer (NK) activity of effector cells obtained from healthy human blood donors. The decrease was observed with SGE from both female and male D. reticulatus fed for either 3 or 5 days on mice, but no significant effect was observed with SGE from unfed ticks or ticks that had fed for 1 day. These results indicate that the tick anti-NK factor(s) is only active after blood-feeding has commenced. Microscopic examination revealed that the first step of NK activity, namely effector/target cell conjugate formation, was affected by SGE. The observed reduction in conjugate formation occurred when effector (but not target) cells were treated with SGE for 30 min, and the effect persisted after 12 h of treatment. Similar but less potent anti-NK activity was detected for SGE from Amblyomma variegatum and Haemaphysalis inermis. By contrast, SGE derived from Ixodes ricinus and Rhipicephalus appendiculatus female ticks did not decrease NK activity. The apparent absence of such activity in these two important vectors of tick-borne viruses suggests that control of NK cells does not play an important role in promoting virus transmission, at least for these particular species.     

Migration of Abdominal Catheter of Ventriculoperitoneal Shunt into the Scrotum

Summary Four cases of migration of the ventriculoperitoneal (V-P) shunt tip through patent processes vaginalis resulting in scrotal hydrocele are presented. These cases are considered a rare complication of V-P shunts and causal mechanisms are discussed with a review of the literature.     

Disappearance of phantom limb pain during cauda equina compression by spinal meningioma and gradual reactivation after decompression

We describe a 65-yr-old woman, whose right lower limb had been amputated at the mid-femoral level because of complicated femur fracture sustained at the age of 5 yr. After amputation, she experienced phantom limb pain (PLP), which gradually decreased in intensity but persisted for 60 yr. At this point the pain diminished progressively, in parallel with the evolution of cauda equina compression caused by an intraspinal tumor. The PLP gradually reappeared over 3 mo after surgical removal of the tumor. IMPLICATIONS: We present a case in which phantom limb pain (PLP) in an amputated leg disappeared during cauda equina compression by meningioma and reactivated after surgical decompression. This case suggests that complete compression or blockade of nerves, a nerve plexus, the cauda equina, or the medullary cord may result in suppression of PLP, and decompression of or recovery from the block may cause reactivation.     

Evaluation of P-POSSUM and O-POSSUM scores in patients with gastric cancer undergoing resection

BACKGROUND/AIMS: The aim of this study was to evaluate the predictive accuracy of P-POSSUM and O-POSSUM models on patients undergoing elective gastric resection. METHODOLOGY: P-POSSUM and O-POSSUM predictor equations for mortality were applied retrospectively to 126 patients who had undergone elective gastrectomy for cancer. Observed mortality rates were compared with rates predicted by P-POSSUM and O-POSSUM using the Hosmer-Lemeshow goodness-of-fit test. Evaluation of the discriminative capability of both models was performed using receiver-operating characteristic (ROC) curve analysis. RESULTS: Overall fourteen deaths were observed. O-POSSUM predicted 15 deaths (chi2=14.61, p=0.13) and P-POSSUM predicted 20 deaths (chi2=25.41, p=0.002) using the Hosmer-Lemeshow test. ROC curves analysis revealed that O-POSSUM had better discriminatory power for mortality compared to P-POSSUM (area under curve=0.880, for O-POSSUM and area under curve=0.703 for P-POSSUM). CONCLUSIONS: These data suggest that O-POSSUM predicts mortality more accurately than P-POSSUM in patients undergoing elective gastrectomy for cancer.     

Synthesis and antimycobacterial activity of pyridylmethylsulfanyl and naphthylmethylsulfanyl derivatives of benzazoles, 1, 2, 4-triazole, and pyridine-2-carbothioamide/-2-carbonitrile

A set of four types of benzazoles, 1, 2, 4-triazole, and pyridine-2-carbonitrile/-2-carbothioamide substituted with 1-naphthylmethylsulfanyl or pyridylmethylsulfanyl was prepared to modify the structure of benzylsulfanyl derivatives of the above-mentioned heterocycles. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. avium, and two strains of M. kansasii. The activities were expressed as the minimum inhibitory concentration (MIC). The MIC values fall into a range of 2 to >1000 micromol/L. Introduction of a pyridyl moiety into the molecule mostly decreased the activity. A naphthyl moiety did not influence the activity in comparison with a phenyl. The most active substances were 4-(3-pyridylmethylsulfanyl)pyridine-2-carbothioamide (7b) (MIC = 2 - >62.5 micromol/L) and 4-(1-naphthylmethylsulfanyl)pyridine-2-carbothioamide (7d) (MIC = 2 - >32 micromol/L).     

The effect of hydroxyurea on the coagulation system in sickle cell anemia and beta-thalassemia intermedia patients: a preliminary study

Hydroxyurea (HU) has been shown to reduce the frequency of vaso-occlusive manifestations in both adults and children with sickle cell disease (SCD), and the induction of hemoglobin F (HbF) is thought to be the underlying mechanism responsible for clinical improvement in some patients. However, there exists no good correlation between the amount of HbF increase and clinical response. Recent studies suggest that increased activity of the coagulation system may be important in the pathogenesis of vascular occlusion in sickle cell disease. To analyze the effect of HU on the coagulation system in children, the authors studied the levels of some coagulation factors and natural inhibitors. Eleven children who had been treated with HU because of SCD (5 patients), sickle- β-thalassemia (3 patients), and β-thalassemia intermedia (3 patients) were enrolled in the study. Levels of the coagulation factors II, V, VII, VIII, IX, X, XI, and XII, and of protein C and protein S, prothrombin times, activated partial thromboplastine times, thrombin times, and reptilase times were measured before the treatment and at the 5th or 6th months of HU therapy when the patients were in a steady-state condition. There was a decrease in all of the coagulation factors except for FIX and FXII and in inhibitors such as protein C and protein S. However, statistically significant decreases were observed only in factor VIII and protein C levels. The rates of decrease were 54.8 and 12.5% ( p = .015 and p = .018) in FVIII and protein C, respectively. This result shows that HU has significant effects on the coagulation and natural inhibitory systems.     

A comparison of four intravenous sedation techniques and Bispectral Index monitoring in sinonasal surgery

This study was performed to investigate the quality of different intravenous sedation techniques, and the correlation between the Bispectral Index (BIS) values and the Observer's Assessment of Alertness/Sedation (OAA/S) scores. Eighty patients undergoing sinonasal surgery were randomly assigned to one of four groups. Group MF received midazolam and fentanyl, group PF received propofol and fentanyl, group MR received midazolam and remifentanil, and group PR received propofol and remifentanil. Heart rate and mean arterial pressure values were not different among the groups. SpO2 decreased only after intravenous medication in groups MF and MR (P < 0.017). Emesis was less common with propofol. A positive relationship existed between the BIS values and OAA/S scores during the operation in all groups and the strongest correlation was observed in group PR (r = 0.565 and P < 0.001). In conclusion, these four intravenous sedation techniques did not change mean arterial pressure, heart rate or SpO2 clinically and produced a similar level of light sedation. The BIS was useful for monitoring of sedation during sinonasal surgery under local anaesthesia with intravenous sedation.     

A prospective randomized study of prophylactic antibiotics in elective laparoscopic cholecystectomy

Background: Elective laparoscopic cholecystectomy (LC) has a low risk for infective complications, but many surgeons still use prophylactic antibiotics. The use of prophylactic antibiotics for LC is inconsistent and varies widely among surgeons. Methods: We performed a prospective double-blind randomized study of prophylactic antibiotics in elective LC. Antibiotics were was given first before the operation and then again 24 h afterward. Group A (n = 49) received 2 g of cefotaxime; group B (n = 43) received 10 ml of isotonic sodium chloride solution. A sample of bile was withdrawn by direct gallbladder puncture for anaerobic and aerobic cultures. Age, sex, weight, duration of surgery (DOS), presence of diabetes mellitus, American Society of Anesthesiologists (ASA) classification, gallbladder rupture, bile and/or stone spillage, gallbladder histological findings, findings from bile cultures positive for bacteria, episodes of colic within 30 days before surgery, length of stay (LOS), and number of septic complications were recorded for both groups. Results: There was no differences between the two groups in terms of sex, weight, DOS, ASA score, gallbladder rupture, bile and/or stone spillage, gallbladder histological findings, findings from bile cultures positive for bacteria, or LOS. One infection occurred in the antibiotic prophylaxis group (2.04%); in the patients not receiving antibiotics, there was one other infection (2.32%). There was no statistical difference between the two groups in infective complications. Conclusion: In patients undergoing elective LC, antibiotic prophylaxis is justified only in high-risk patients. In all other patients, antibiotic prophylaxis does not seem to affect the incidence of postoperative infective complications. In low-risk patients, eliminating the unnecessary use of prophylactic antibiotics would result in a cost reduction; moreover, it would lower the risk of adverse reaction and reduce microbial resistance. Presented at the combined meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) and the 8th World Congress of Endoscopic Surgery, New York, NY, USA, 13–16 March 2002