Polymerase chain reaction amplification from Plasmodium falciparum on dried blood spots.

We report a simple method for the polymerase chain reaction (PCR) amplification of whole blood samples collected on filter paper. The blood spot was used directly in the PCR after treatment with methanol. We evaluated this assay using clinical samples collected from subjects in a Plasmodium falciparum vaccine trial and from samples collected during a hospital-based study in Thailand. Specimens prepared from heparinized blood samples were successfully amplified following pretreatment with heparinase. Sensitivity was 100% when compared with thick blood film results in the vaccine trial (range = 4-60 parasites/microliters, median = 8/microliters) and 94.6% (range = 3-133,988 parasites/microliters, median = 616/microliters) in the hospital study.

Preliminary assessment of captopril sonography in screening for renal artery stenosis.

RATIONALE AND OBJECTIVES: We assessed the usefulness of the resistive index (RI) and renal length in predicting a significant renal artery stenosis (RAS) and evaluated the effect of captopril on the RI in kidneys with and without a significant RAS. METHODS: The RIs and renal lengths of both kidneys were measured in 39 patients who were referred for captopril renography for suspected renovascular hypertension. The difference in RIs (delta RI), the smaller RI (SRI), the difference in lengths (delta L), and the shorter length (SL) of the patient's two kidneys were determined. The accuracy of each of these parameters was calculated using captopril renography (n = 39) and arteriography (n = 9) as the gold standards. RESULTS: There was a significant difference in the delta RI (P < .05), SRI (p < .001), and delta L (p < .05) in patients with a positive captopril renogram for a significant RAS. Captopril increased delta RI (p = .052) in patients with a positive captopril renogram (n = 6). Use of an SRI threshold of less than .55 resulted in ultrasound being as accurate as captopril renography in predicting an angiographically documented stenosis of greater than or equal to 50%. CONCLUSION: The RI and renal length are useful in detecting a significant RAS. In this preliminary study, captopril was shown to increase delta RI in patients with a significant RAS, but larger prospective studies are necessary to further assess the value of captopril sonography in detecting a significant RAS.

Alterations in plasma levels and complexing of Gc (vitamin D-binding protein) in rats with endotoxic shock.

Septic shock is known to involve increased metabolism of arachidonic acid and generation of certain eicosanoids. Recently, a new extracellular pool of unsaturated fatty acids including arachidonate has been found in relation to group-specific component (Gc), a vitamin D-binding plasma protein that sequesters monomeric G-actin. Since complexing with G-actin displaces fatty acids, possible alterations in plasma levels of Gc and extent of complexing were sought in serial samples obtained from rats with shock induced by Salmonella enteritidis endotoxin (12.5-15 mg kg-1). Gc levels in animals receiving endotoxin exhibited bimodal alterations, with a significant reduction (P less than 0.001) at 1 hour, followed by a progressive elevation to 160% of starting concentrations at 6 days in animals that survived, whereas in sham-injected animals the change observed was a continuous rise to 147% at 6 days. A statistically significant increase in the percentage of Gc complexed was observed in all endotoxemic rats from 2 hours onward (P less than 0.01), in contrast to sham-injected animals, in which the percentage of Gc complexed remained at less than 5%. Levels in survivors peaked at 30 +/- 5.2% at 8 hours and then decreased to normal (2 +/- 0.9%) by 6 days (n = 7), whereas in nonsurvivors complexed Gc continued to rise until time of death (66-80%) at 6-12 hours (n = 4). Correlation of these results with glucose, transaminases, and immunoreactive TXB2 and 6-keto-PGF1 alpha indicated that decreased absolute levels of Gc represent a consistent early change in endotoxic shock and that the percentage of Gc complexed is an accurate prognostic indicator of severity.

Alterations in Gc levels and complexing in septic shock.

Septic shock involves increased generation of eicosanoids from arachidonic acid. Gc (vitamin D-binding protein) has been recently found to bind the parent molecule arachidonic acid but can also complex actin released as a result of tissue damage which causes displacement of bound arachidonic acid. Possible changes in serum levels of Gc and extent of complexing were therefore investigated in patients with gram-negative sepsis. As compared to healthy controls, serum levels of Gc were significantly decreased in patients with septic shock (P less than 0.01). Moreover, the percentages of Gc circulating in complexed form were significantly increased (P less than 0.01) and correlated strongly with disease severity, with levels often greater than 90% in patients who died (normal mean 8% +/- 3). These results suggest a hitherto unsuspected role for Gc in septic shock syndrome.

Predicting survival in fulminant hepatic failure using serum Gc protein concentrations.

Plasma Ge protein sequesters actin released into the circulation after massive hepatocyte necrosis, but is greatly depleted in the process. In fulminant hepatic failure (FHF), Gc is present in serum both as a complex with actin and as unbound protein, the latter becoming completely exhausted in those patients with the most severe FHF. In the present study, 47 consecutive patients with FHF, 39 of whom were the result of acetaminophen (AC) overdose, were evaluated to determine whether measurement of Gc protein levels could be used to predict survival. Using serum samples obtained shortly after admission as well as later samples, levels for total Gc protein, percentage of Gc complexed with actin, and calculated unbound Gc remaining in serum were compared for survivors and those who died of their illness. The most marked changes were present in unbound Gc levels in nonsurvivors, the mean of which for follow-up samples was 10% of normal mean values, as compared with 23% of normal mean values in those who survived (P < .01). Using a cutoff value for unbound Gc protein of > or = 34 micrograms/mL to predict survival, outcome was correctly predicted in 32 of 47 (68%) patients using early samples, and in 24 of 27 (89%) patients using later sera. No differences were observed between values and/or outcome in AC and non-AC cases. Measurement of Gc protein level correctly predicted all patients dying of hepatic failure. This single measurement compares favorably with multifactorial predictive models, such as the King's College model, and might be a useful test for patients being considered for transplantation.