Quantitative analysis of Fas and bcl-2 expression in hematopoietic precursors

BACKGROUND AND OBJECTIVES

We investigated the expression of bcl-2 and CD95 (Apo1-/Fas) on CD34+ cells obtained from bone marrow (BM), mobilized peripheral blood (MPB), and umbilical cord blood (UCB) samples. The expression of bcl-2 and Fas was then compared with that of other markers usually associated with immaturity; functional tests using the agonistic antibody anti- Fas CH11 were also carried out.

DESIGN AND METHODS

The analysis was performed by flow cytometry on purified CD34+ cells in a three (CD95 PE, CD34 APC and CD71 FITC) and in a four (CD38 PE, HLA-DR PerCP, CD34 APC and bcl-2 FITC) fluorescence assay.

RESULTS

The results were expressed as mean fluorescence index (MFI); bcl-2 expression was significantly higher (p < 0.001) in BM (3.73 +/- 0.63) than in MPB (2.47 +/- 0.39) and UCB (2.38 +/- 0.58); Fas was significantly less expressed (p < 0.001) in UCB (1.27 +/- 0.78) than in MBP (3.63 +/- 2.19) and BM (4.56 +/- 1.69). CD34 expression was significantly (p < 0.001) brighter in UCB compared to in MBP and BM, while CD38 and CD71 were significantly (p = 0.005 and p < 0.001, respectively) more expressed in BM than in MPB and UCB. Fas values were directly correlated to CD38; both Fas and bcl-2 were directly related to CD71 and inversely to CD34. Culture assays showed that hematopoietic precursor cells from BM, MPB and UCB had a low susceptibility to undergo Fas-mediated apoptosis.

INTERPRETATION AND CONCLUSIONS

In conclusion, bcl-2 and Fas are less expressed in UCB than in MPB and BM; early hematopoietic precursor cells are relatively resistant to CD95-triggered apoptosis; the observed correlation between Fas/bcl-2 and markers of immaturity suggests that they may be determinants of commitment in early hematopoietic precursors.

Protocol violations in community-based rTPA stroke treatment are associated with symptomatic intracerebral hemorrhage

BACKGROUND

Recombinant tissue plasminogen activator (rTPA) is an established treatment for acute ischemic stroke. The rate and type of protocol violations in rTPA use and their effect on patient outcomes in this setting are not well understood.

OBJECTIVE

The objective of this study was to examine associations between protocol violations and outcomes in community-based rTPA use.

METHODS

We reviewed medical records of stroke patients treated with rTPA in 10 acute-care hospitals in Indianapolis from July 1996 to February 1998 and assessed complications and outcome. Retrospective National Institute of Health Stroke Scale (on admission and discharge), Canadian Neurological Scale, and length of hospital stay were calculated. Appropriate use of rTPA was determined by the National Institute of Neurological Disorders and Stroke (NINDS) protocol.

RESULTS

Fifty patients (mean age, 66 years; 76% white; 56% men) were treated by general neurologists (70%), stroke neurologists (24%), or emergency physicians (6%). Mean times to hospital arrival, brain CT, and start of rTPA infusion were 44, 86, and 141 minutes, respectively. In-hospital mortality rate was 10% (4 intracerebral hemorrhage [ICH], 1 cardiogenic shock). Complications were more frequent among patients with protocol violations (n=8) compared with those without all hemorrhages (75% versus 10%, P:<0.001), symptomatic ICH (38% versus 5%, P:<0.02), and ICH attributable to rTPA, occurring within 36 hours (38% versus 2.4%, P:<0.01), respectively.

CONCLUSIONS

NINDS protocol violations are relatively common and are associated with symptomatic cerebral and systemic hemorrhages. When the NINDS protocol is strictly followed, hemorrhage rates in community-based rTPA use are similar to those in the NINDS trial.

Prevention of pin track infection in external fixation with silver coated pins: clinical and microbiological results

Pin tract infection is a frequent complication of external fixation; according to literature its frequency ranges from 2-30%. The recent introduction of silver coating of polymeric materials was found to decrease bacterial adhesion; its clinical use with Foley catheters and central venous catheters led to significant results. To verify the ability of the same silver coating to decrease the bacterial colonization on external fixation screws, a prospective randomized study was carried out on 24 male patients; a total of 106 screws were implanted in the lower limb to fix femoral or tibial diaphyseal fractures: 50 were coated with silver and 56 were commercially available stainless steel screws. Although the coated screws resulted in a lower rate of positive cultures (30.0%) than the uncoated screws (42.9%), this difference was not statistically significant (p = 0.243). The clinical behavior of the coated screws did not differ from that of the uncoated ones. Furthermore, the implant of silver-coated screws resulted in a significant increase in the silver serum level. These results led us to consider it ethically unacceptable to continue this investigation.

Prevention of pin track infection in external fixation with silver coated pins: clinical and microbiological results

Pin tract infection is a frequent complication of external fixation; according to literature its frequency ranges from 2-30%. The recent introduction of silver coating of polymeric materials was found to decrease bacterial adhesion; its clinical use with Foley catheters and central venous catheters led to significant results. To verify the ability of the same silver coating to decrease the bacterial colonization on external fixation screws, a prospective randomized study was carried out on 24 male patients; a total of 106 screws were implanted in the lower limb to fix femoral or tibial diaphyseal fractures: 50 were coated with silver and 56 were commercially available stainless steel screws. Although the coated screws resulted in a lower rate of positive cultures (30.0%) than the uncoated screws (42.9%), this difference was not statistically significant (p = 0.243). The clinical behavior of the coated screws did not differ from that of the uncoated ones. Furthermore, the implant of silver-coated screws resulted in a significant increase in the silver serum level. These results led us to consider it ethically unacceptable to continue this investigation.

Prevention of pin track infection in external fixation with silver coated pins: clinical and microbiological results

Pin tract infection is a frequent complication of external fixation; according to literature its frequency ranges from 2-30%. The recent introduction of silver coating of polymeric materials was found to decrease bacterial adhesion; its clinical use with Foley catheters and central venous catheters led to significant results. To verify the ability of the same silver coating to decrease the bacterial colonization on external fixation screws, a prospective randomized study was carried out on 24 male patients; a total of 106 screws were implanted in the lower limb to fix femoral or tibial diaphyseal fractures: 50 were coated with silver and 56 were commercially available stainless steel screws. Although the coated screws resulted in a lower rate of positive cultures (30.0%) than the uncoated screws (42.9%), this difference was not statistically significant (p = 0.243). The clinical behavior of the coated screws did not differ from that of the uncoated ones. Furthermore, the implant of silver-coated screws resulted in a significant increase in the silver serum level. These results led us to consider it ethically unacceptable to continue this investigation.

Risk factors for intracerebral and subarachnoid hemorrhage among Hispanics and non-Hispanic whites in a New Mexico community

BACKGROUND AND OBJECTIVE

A higher incidence of spontaneous intracerebral and subarachnoid hemorrhage among Hispanics than non-Hispanic whites has been measured in Bernalillo County, New Mexico. In an attempt to explain these differences, we compared historical vascular risk factors between Hispanics and non-Hispanic whites living in this community.

METHODS

An ongoing telephone survey, the Behavioral Risk Factor Surveillance System, collected annual data about vascular risk factors among non-institutionalized, randomly selected adults. Data covering 6 years, 1988-1993, were analyzed.

RESULTS

There were 843 Hispanic and 1,635 non-Hispanic white residents of Bernalillo County, New Mexico, who participated in this survey. Because Hispanics were significantly younger than non-Hispanic whites (37.7 vs. 43.4 years, p < 0.001), all other comparisons were adjusted for age. Prevalence of hypertension was similar between these ethnic groups (15-17%). Prevalence of alcohol drinking considered risky for abuse was similar between these ethnic groups (5-6%), but was significantly higher among Hispanic men than women (8.5 vs. 1.6%, p < 0.001). The quantity of alcohol consumption among those at risk for abuse was similar between these ethnic groups. Prevalence of current cigarette smoking was similar between these ethnic groups (22-23%), but Hispanics smoked significantly less than non-Hispanic whites (11.4 vs. 15.2 cigarettes per day, p < 0.001) and among non-Hispanic whites, men smoked significantly more than women (17.0 vs. 13.4 cigarettes per day, p = 0.001).

CONCLUSION

The vascular risk factors which we compared between Hispanics and non-Hispanic whites do not help to explain the higher incidence of hemorrhagic strokes among the Hispanics in Bernalillo County, New Mexico. Additional risk factors for hemorrhagic strokes in these two ethnic groups should be studied.

Intestinal parasitic infections in an institution for the mentally retarded

Of 550 mentally retarded patients in an Italian institution, 125 (23%) were found to be infected with intestinal parasites. The infections were most frequent in young men, those with severe mental retardation, the chronically institutionalized and those living in older wards. Ninety-four (75.2%) of the parasitised subjects were infected only with protozoa, 25 (20%) only with helminths, and six (4.8%) with protozoa and helminths. Entamoeba histolytica and E. dispar infections were detected, but at low prevalences; in-vitro culture in Robinson's medium and isoenzyme electrophoresis of the cloned amoebic isolates indicated one infection with E. histolytica (zymodeme XII) and two infections with E. dispar (zymodemes I and III). All three Entamoeba-positive subjects were asymptomatic cyst-passers. Antibodies to E. histolytica were detected in seven (1%) of the sera from the 550 patients examined; only one of these was a carrier of an E. dispar strain at the time of investigation. The low prevalences of all the parasitic infections and of the amoebic infections in particular (compared with those observed previously in institutions for the mentally retarded) reflect relatively good facilities and sanitary conditions, an adequate number of well trained staff and good control of the more susceptible subjects.

Inhibition of HMG-CoA reductase activity by hypercholesterolaemia reduces leukocyte recruitment and MCP-1 production

To clarify the relationship between cholesterol homeostasis and inflammation we studied the effect of hypercholesterolaemia on in vivo cytokine production and leukocyte migration, in a murine model of local inflammation. Hypercholesterolaemia reduced of 40% the leukocyte recruitment by inhibiting interleukin-6 and monocyte chemotactic protein-1 production in the pouch exudate, without affecting vascular permeability or leukocytes motility.

Inhibition of monocyte chemotactic protein-1 synthesis by statins

The beneficial effects of statins on the reduction of cardiovascular events has been partly attributed to their anti-inflammatory properties. In the complex of the different pathogenetic events leading to atherosclerosis, recent data suggest a central role of monocyte chemotactic protein-1 (MCP-1), because mice knock-out for MCP-1 or its receptor CC-chemokine receptor 2 were considerably resistant to plaque formation. In this study we investigated the effect of different statins on in vitro and in vivo production of MCP-1. Lovastatin and simvastatin caused a dose-dependent inhibition of MCP-1 production in peripheral blood mononuclear cells exposed to lipopolysaccharide or inactivated Streptococcus hemoliticus and in human endothelial cells exposed to interleukin-1beta. The addition of mevalonate overrode the inhibitory effect of statins indicating that mevalonate-derived products are important for chemokine production. The in vivo anti-inflammatory effect of statins was investigated using the mouse air-pouch model of local inflammation. Lovastatin and pravastatin were orally administered to mice according to a treatment schedule that significantly inhibited the hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity without affecting total blood cholesterol. At the dose of 10 mg/kg, lovastatin and pravastatin reduced by approximately 50% the lipopolysaccharide-induced leukocytes recruitment and the exudate MCP-1 production. In conclusion, statins, by inhibiting mevalonate-derived products, reduced both in vitro and in vivo the production of chemokines involved in leukocyte migration, and this effect is unrelated to their cholesterol-lowering action.