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Biomedical subjects

M F Lutz

Publications and source records attributed to M F Lutz.

8 recordsLinked to original sources
PubMed2006

[A case of delayed fat embolism after a vertebral osteosynthesis].

A 37-year-old woman presented an acute respiratory distress syndrome six days after a post-traumatic vertebral osteosynthesis. First, a pulmonary embolism was suspected, and a thrombolysis realised. This diagnosis was secondary excluded, and the diagnosis of probable fatty embolism was established by the bronchoalveolar lavage. So, this case shows a delayed presentation of fatty embolism and permits a discussion about clinical presentation, and diagnosis methods of such pathology.

Acute Disease↗
PubMed1997

Situation models and abstract ownership relations.

Six experiments used a fan-effect paradigm to test whether people can use the abstract relation of ownership to help integrate information into situation models. People studied sentences of the form The [person] owns/is buying the [object] for a later recognition test. The integration of sentences into a situation model (as evidenced by an attenuated or absent fan effect) was observed when the verb phrase referred to a specific event (is buying) and the objects could all be bought in the same place (e.g., a drugstore). This organization did not occur either when the verb phrase referred to general ownership (owns) or when the items were unlikely to be purchased in a single location (e.g., television and car). It was concluded that although abstract relations can be used to segregate information into sets that can be integrated into situation models, this integration is more likely when it can be embedded within a spatial-temporal framework.

Attention↗
PubMed1984

Stimulation of ATP synthesis in hypothermically perfused dog kidneys by adenosine and PO4.

During continuous hypothermic perfusion of dog kidneys there occurs a gradual decrease in ATP from about 1.4 to 0.6 mumol/g wet wt after 5 days of preservation. The loss of ATP can be prevented by including both adenosine (10 mM) and PO4 (25 mM) in the perfusate. Under these conditions kidney cortex ATP levels were more than double control values--3.5 mumol/g wet wt. Both adenosine and PO4 were necessary since omission of one substance resulted in no net synthesis of ATP. Furthermore, these high levels of ATP were obtained only if adequate concentrations of adenosine were maintained during perfusion. Following 3 days of perfusion the adenosine level in the perfusate decreased to about 1 mM and under this condition ATP levels were low. Adenosine levels were maintained in the perfusate by two methods: (1) addition of fresh perfusate or (2) pretreatment of the kidney with the adenosine deaminase inhibitor--deoxycoformycin. The increased levels of ATP appear directly related to the availability of nucleotide precursors and the presence of inhibitors of the enzymes involved in the catabolism of nucleotides and nucleosides (PO4 and deoxycoformycin). Mitochondrial activity was similar in kidneys with high or low ATP levels following 5 days of preservation.

Adenine Nucleotides↗
PubMed1984

Effects of hypothermic perfusion of kidneys on tissue and mitochondrial phospholipids.

The changes in the level of phospholipids in kidney tissue and isolated mitochondria from dog kidneys perfused hypothermically (6-8 degrees C) for 1, 3, and 5 days were compared. Following 1 day of perfusion there was no change in total tissue phosphatidylserine (PS), a 25% decrease in the level of phosphatidylethanolamine (PE), and a 16% decrease in phosphatidylcholine (PC). No further decrease was observed with longer perfusion times. In fact, an increase in the level of PE occurred between the third and fifth days. Mitochondria isolated from perfused kidneys also showed a slight decrease in PE and PC following 1 day, no further change at 3 days, and an increase at Day 5. The loss of tissue phospholipids does not appear related to the viability of perfused kidneys. The major loss occurs within 1 day of perfusion and kidneys perfused up to 3 days are fully viable. Five-day perfused kidneys are nonviable, but show no greater loss of phospholipids than the viable 1- or 3-day perfused kidneys.

Animals↗
PubMed1984

Comparison of the effect of 3- and 5-day hypothermic perfusion of dog kidneys on metabolism of tissue slices.

Hypothermic perfusion effectively preserves the viability of kidneys for 3 days. Long-term preservation (5 days or greater) has not been consistently obtained. In this study, the differences between kidneys perfused for 3 and 5 days were compared by determining the "integrated-metabolic" capabilities of tissue slices incubated in vitro at 30 degrees C. The "integrated-metabolic" parameters determined include (1) respiration rates, (2) cell volume regulation [total tissue water (TTW) and saccharide permeable space], (3) rate of reaccumulation of K+ and pumping of Na+, (4) maintenance of ATP concentrations, and (5) mitochondrial functions. Conditions that result in high and low concentrations of ATP following perfusion of kidneys for 5 days were also compared for effects on tissue slice metabolism. The results indicate that energy metabolism in tissue slices is well preserved under all conditions and times of perfusion of kidneys. This includes average respiration rates (315 +/- 50, 275 +/- 35, and 255 +/- 45 mumol O2/hr/g dry wt at 0, 3, and 5 days, respectively, mitochondrial function [respiratory control ratio (RCR) = 4.6, 4.0, and 4.1 for 0, 3, and 5 days, respectively], and steady-state concentration of ATP in slices after incubation (4.0 +/- 1.45, 3.9 +/- 1.28, and 3.3 +/- 0.81 mumol/g/dry wt, for 0, 3, and 5 days, respectively). The primary differences between 3- and 5-day perfused kidneys were the capability of the slices to regulate cell volume and reaccumulate K+. Slices from kidneys perfused for 3 days maintained the TTW at 3.8 kg/kg dry wt, a value similar to that of control tissue slices. However, slices from 5-day perfused kidneys remained swollen (TTW = 4.6 kg/kg dry wt). Also, slices from the 5-day perfused kidney pumped K+ at less than one-half the rate found in slices from control or 3-day preserved kidneys. No significant differences were apparent in the permeability properties of the tissue slices from kidneys perfused for 3 and 5 days to radiolabeled saccharides. The defects in membrane-linked transport functions, resulting from long-term kidney perfusion, were reduced in kidneys containing a high concentration of ATP. The results suggest that one factor which may limit successful preservation of kidneys is the increased membrane permeability (to electrolytes) which is partially prevented by maintaining elevated concentrations of tissue ATP during perfusion.

Adenosine Triphosphate↗
PubMed1983

Calcium paradox in canine kidneys.

Isolated perfusion of the heart with a Ca2+-free perfusate followed by a Ca2+-containing perfusate causes dramatic alterations in the physiology and biochemistry of the tissue, a phenomenon known as the calcium paradox. A similar paradoxical effect of Ca2+ has also been reported to occur in the kidney. In this study an attempt was made to reproduce the calcium paradox in canine kidneys and to characterize more fully its metabolic consequences. Canine kidneys were perfused with Krebs-Henseliet bicarbonate buffer free of Ca2+ for 30 min followed by perfusion with Ca2+ (1.5 mM). Unlike previously reported results no sudden decrease in flow was there a Ca2+-related sharp rise in rate of release of lactic dehydrogenase. In addition, we found no significant change in the level of tissue adenine nucleotides or functionality of isolated mitochondria. It is concluded that there is no calcium paradox in canine kidney under these conditions and it is suggested that the Ca2+ paradox may be characteristics only of muscle tissue that can undergo Ca2+-dependent contraction.

Animals↗