Invasion of hereditary ovalocytes by Plasmodium falciparum in vitro and its relation to intracellular ATP concentration

Hereditary ovalocytes (stomatocytic ovalocytes), when examined within 1-2 days from the time that the blood sample is drawn, are invaded by Plasmodium falciparum in culture to the extent of at least 55% of normal control cells. The ovalocytes have extremely rigid membranes, characterised by a shear elastic modulus some 3-4 times greater than that of normal cells. The extent of invasion falls off very much more rapidly than that into normal cells on storage, and we surmise that this is the reason for earlier reports of resistance of ovalocytes to malarial invasion in vitro. The initial loss of susceptibility to invasion with time is not accompanied by any change in membrane rigidity, but is primarily a consequence of a rapid decline in intracellular ATP concentration: this falls to below the threshold level required for invasion (approx. 0.1 mM) over a period in which the ATP in normal cells remains almost constant. Incubation in a metabolic regenerating medium leads to a rise in the intracellular ATP concentration and invasion by P. falciparum is recovered, though to a much lower extent than in normal cells. The resistance of ovalocytes to invasion becomes irreversible, due possibly to degradative processes in the membrane, on further storage. The developing parasites in ovalocytes have a reduced number of merozoites and show distinct morphological abnormalities.     

An electroencephalographic classification for coma

BACKGROUND: The assessment of thalamocortical function in comatose patients in the intensive care unit (ICU) can be difficult to determine. Since the electroencephalogram (EEG) affords such assessment, we have developed an EEG classification for comatose patients in our general ICU. METHODS: One hundred EEGs were classified in a blinded fashion by two EEGers, using our method and that of Synek. Interobserver agreement was assessed using kappa score determination. RESULTS: Kappa scores were 0.90 for our system and 0.75 for the Synek system. (The Kappa score represents the inter-rater agreement that is beyond chance; 0.90 is almost perfect agreement, while 0.75 is substantial agreement). CONCLUSION: Our system for classifying EEGs in comatose patients has a higher interobserver reliability than one that was previously published. This EEG classification scheme should be useful in clinical electrophysiological research involving ICU patients, allowing for internal consistency and comparisons among centres.     

Cell behavior and signal molecule involvement in a case study of malignant histiocytosis: a negative model of morphine as an immunoregulator

OBJECTIVE: This paper identifies specific data items for use by state and local agencies in a maternal and child oral health needs assessment model. METHODS: A modified Delphi approach was used to develop consensus on items for inclusion in the data set and their relative importance. Initially, 31 data items were chosen from several national sources. All state dental directors, along with other selected administrators and advisory committee members for this process, were asked to categorize each of the data items as core (essential), important but optional, or of lesser importance. Short comments about each data item were accepted, as were additions to the list of data items. Two rounds of comments were held. RESULTS: Eleven data items/types of information were selected as core items to be included in all needs assessments. All but one of these items were determined by the scores of the respondents. The advisory committee strongly recommended that at least one core item relate to the public's perception of oral health. Some differences in perceived importance of several items existed among the state dental directors, local dental directors, and the advisory committee. Twenty-one items were identified as being important, but optional, and seven were considered less than important and not included in the model data set. CONCLUSIONS: A modified Delphi approach facilitated the development of core and optional data items for a model oral health needs assessment. This model has potential for a common reporting mechanism so that states and local dental programs can share data.     

Establishment and molecular characterization of five cell lines derived from renal and extrarenal malignant rhabdoid tumors

Malignant rhabdoid tumor (MRT) is a rare, enigmatic childhood cancer characterized by extreme aggressiveness and resistance to chemotherapy. To understand better the origin of the tumor and the mechanisms by which it develops and resists treatment, five cell lines were established from patients presenting with MRT (two renal and three extrarenal tumors). All of the cell lines display the light microscopic and ultrastructural features, as well as the variable immunohistochemical profile, characteristic of MRT. All are capable of forming tumors in nude mice. Three of the cell lines have detectable abnormalities of chromosome 22: one a t(22, 22) unbalanced translocation and two others a loss of heterozygosity of polymerase chain reaction-based microsatellite markers. Northern blot analysis showed that overexpression of the c-myc message was a consistent characteristic of the five MRTs evaluated. Although mutations of the p53 gene were not detectable by sequence analysis, all of the cell lines showed nuclear accumulation of the p53 protein by an immunocytochemical analysis in a minority of the cells. This result suggests that dysfunction in a p53-dependent apoptotic pathway might play a role in the multiple drug resistance phenotype of these tumors.     

A technique revisited: hemodynamic comparison of closed- and open-chest cardiac massage during human cardiopulmonary resuscitation

OBJECTIVE: To compare the hemodynamics of closed-chest cardiac massage vs. open-chest cardiac massage in patients resuscitated from cardiac arrest that occurred outside of the hospital. DESIGN: Prospective, non-outcome, case series. SETTING: Large urban emergency department. PATIENTS: Ten adult, normothermic, nontraumatic, out-of-hospital, cardiac arrest patients who failed advanced cardiac life support (ACLS) therapy. INTERVENTIONS: Patients presenting to the hospital in cardiac arrest were managed according to the ACLS protocol at the clinician's discretion. Proximal aortic and central venous pressure catheters were placed to measure arteriovenous compression- and relaxation-phase pressure gradients. After 5 mins of baseline measurements during closed-chest cardiac massage, patients underwent a left lateral thoracotomy, and open-chest cardiac massage was performed for 5 mins. MEASUREMENTS AND MAIN RESULTS: The mean coronary perfusion pressure and compression-phase pressure gradients were 7.3 +/- 5.7 and 6.2 +/- 5.4 mm Hg, respectively, during closed-chest cardiac massage, while increasing to 32.6 +/- 17.8 and 32.6 +/- 29.9 mm Hg, respectively, during open-chest cardiac massage. The differences between both measurements were statistically significant (p < .05). CONCLUSIONS: Open-chest cardiac massage is superior to closed-chest cardiac massage in providing relaxation-phase and compression-phase pressure gradients during cardiac arrest in patients failing current ACLS protocols. During open-chest cardiac massage, all patients exceeded the minimum coronary perfusion pressure of 15 mm Hg, which is recommended to obtain a return of spontaneous circulation. Further outcome studies are needed to determine the timeliness and appropriate indications for open-chest cardiac massage.