Evidence that the number of hematopoietic stem cells per animal is conserved in mammals

Humans and larger mammals require more blood cells per lifetime than mice because of their larger size and longer life expectancy. To investigate this evolutionary adaptation, we calculated the total number of nucleated marrow cells (NMCs) per cat, observing the distribution of (59)Fe to marrow, then multiplied this value (1.9 +/- 0.9 x 10(10) [mean +/- SD]) times the frequency of feline hematopoietic stem cells (HSCs) (6 HSCs/10(7) NMCs) to derive the total number of HSCs per cat (11 400 +/- 5400). Surprisingly, when the total number of HSCs per mouse was calculated with a similar experimental and computational approach, the value was equivalent. These data imply that the output of differentiated cells per feline HSC must vastly exceed that of murine HSCs. Furthermore, if the total number of human HSCs were also equivalent to the total number of HSCs in cat and mouse, the frequency of human HSCs would be 0.7 to 1.5 HSCs/10(8) NMCs, a frequency that is 20-fold less than estimated by the NOD/SCID repopulating assay.     

The effects of hypoglycemia and ethanol on rat performance in the radial-arm maze

A deficit in blood glucose (BG) (hypoglycemia, HG) causes a characteristic array of physiological sequelae, symptoms and cognitive impairment in human subjects. However, the performance of hypoglycemic animal subjects in the standard paradigms of behavioral pharmacology has received little research attention. The primary purpose of these experiments was to determine the effect of insulin-produced HG on spatial working memory in rats trained in the radial-arm maze (RAM), using a noninterrupted (win-shift) procedure. A second aim was to further investigate possible interaction between HG and ethanol administration since potentiation between the drugs' depressant effects has been reported for rat spontaneous motor activity (SMA). Insulin administration (resulting in BG levels approximately 65% of control levels) was combined factorially with ethanol treatment in two experiments. HG significantly increased time required to complete RAM trials in both experiments, but did not impair accuracy of arm choice. In the second experiment, ethanol was administered only once to minimize development of tolerance, and under these conditions, ethanol at 1500 mg/kg impaired arm-choice accuracy and marginally potentiated HG-produced slowing of running time. The current results appear somewhat similar to previously reported effects of HG on reaction time in human subjects.     

Interpreting the mechanisms of continuous renal replacement therapy in sepsis: the peak concentration hypothesis

Severe sepsis and septic shock are the primary causes of multiple organ dysfunction syndrome (MODS), which is the most frequent cause of death in intensive care unit patients. Many water-soluble mediators with pro- and anti-inflammatory action such as TNF, IL-6, IL-8, and IL-10 play a strategic role in septic syndrome. In intensive care medicine, blocking any one mediator has not led to a measurable outcome improvement in patients with sepsis. CRRT is a continuously acting therapy, which removes in a nonselective way pro- and anti-inflammatory mediators; "the peak concentration hypothesis" is the concept of cutting peaks of soluble mediators through continuous hemofiltration. Furthermore, there is evidence of increased efficacy of high-volume hemofiltration compared to conventional CVVH, and other blood purification techniques that utilize large-pore membranes or sorbent plasmafiltration are conceptually interesting.     

Children's memory for trauma and positive experiences

Characteristics of children's memory for a trauma and for a positive event were compared and relationships of memory characteristics to trauma symptoms examined in 30 children who experienced a traumatic event. Results revealed that memories for trauma tended to have less sensory detail and coherence, yet have more meaning and impact than did memories for positive experiences. Sexual traumas, offender relationship, and perceived life threat were associated with memory characteristics. Few relationships between memory characteristics and trauma symptoms were found. Therapist ratings of child memory characteristics were correlated with some child trauma memory characteristic reports. These results are consistent with other studies. Possible explanations include divided attention during the traumatic event and cognitive avoidance occurring after the event.     

Assessment of psychological functioning in adolescent earthquake victims in Colombia using the MMPI-A

The earthquake that hit Armenia, Colombia, on January 25, 1999, dramatically impacted the lives of thousands of people, including children and adolescents. This study used the Hispanic MMPI-A to clinically assess for ongoing psychopathology in a group of 59 adolescent earthquake victims. Their scores on the basic, content, and supplementary scales of the instrument were compared to those of a control group of 62 Colombian adolescents with similar socioeconomic, educational, and ethnic backgrounds. The results showed no clinically significant elevations for the earthquake victims indicating that the disaster had not resulted in diagnosable psychopathology. When compared to controls, earthquake victims showed significant elevations on D, Pt, and Sc indicating that they were mildly affected (but within the normal range) by the earthquake. The results are discussed in the context of cultural factors and the contemporary disaster and resiliency literature.     

Anesthetic considerations in a patient with severe aortic stenosis for craniotomy

Severe aortic stenosis can pose a serious hazard for noncardiac surgery as patients with this condition have a high risk for developing perioperative cardiac complications. We describe the anesthetic management of a patient with a malignant brain tumor who was found to have severe aortic stenosis during preanesthetic evaluation. She underwent palliative balloon aortic valvuloplasty prior to surgery, and this combined with appropriate monitoring and drug therapy resulted in a satisfactory outcome. Adverse intraoperative events like hypotension and left ventricular failure occurred; however, these events were transient and responded to treatment.