A rapid and simplified ELISA using whole blood samples of Schistosoma japonicum-infected rabbits

A rapid and simplified ELISA using whole blood samples of Schistosoma japonicum-infected rabbits was compared with a conventional ELISA. This whole-blood ELISA has advantages. The volume of crude egg antigens, whole blood samples, and conjugates was only 0.05 ml. The incubation time was shortened to 5 minutes. Wells were washed three to five times with PBS-Tween after each procedure. Optical density values were measured in 10 minutes after transfer of 0.1 ml of substrate. Constant temperature was not necessary. The entire procedure took only 20-30 minutes.     

Effective treatment of diabetic diarrhoea with somatostatin analogue, octreotide.

A 22 year old insulin dependent diabetic with high volume, secretory chronic diarrhoea refractory to standard andiarrhoeal drugs was treated with the somatostatin analogue octreotide, 50 micrograms twice daily by subcutaneous injection. She improved markedly with a decrease in mean stool weight from 1170 g/24 h range 440-2900 g) to 440 g/24 h (range 180-800 g) (p < 0.05). Stool frequency also decreased from six (range two to 12) to one (range one to three) bowel movements per day (p < 0.01). Mouth to caecum transit time increased from 45 minutes to > 210 minutes, although total gut transit time was unchanged and remained rapid at nine hours. Thus octreotide can reduce stool volume and frequency in high volume diabetic diarrhoea when conventional antidiarrhoeal agents have failed. Its therapeutic benefit appeared to be predominantly related to a marked increase in mouth to caecum transit time.     

Autologous low density lipoprotein enhances platelet aggregation in whole blood, as measured by in vitro filtragometry

The influence of low density lipoprotein (LDL) on platelet aggregability was studied using filtragometry and conventional Born aggregometry in vitro. Three different concentrations of autologous LDL, obtained from 9 healthy male volunteers, were incubated for 20 min, at 37°C, with whole blood anticoagulated with low molecular weight heparin (filtragometry) or citrated platelet-rich plasma (PRP; Born aggregometry). The LDL-cholesterol concentration was increased from 1.7 ± 0.2 mmol/1 to 2.4 ± 0.2, 3.5 ± 0.3 and 5.3 ± 0.5 mmol/l, respectively. Adenosine diphospate (ADP)-induced platelet aggregation in whole blood was enhanced in a dose dependent manner by LDL, as assessed by filtragometry (ADP cone, range 0.1-0.3 μM). Platelet aggregability in PRP (Born) was not affected by LDL at the ED(50) for ADP-induced platelet aggregation (i.e. 1-4 μM ADP). The marked platelet activation caused by the high ADP concentrations used with conventional Born aggregometry may have masked a modest LDL-induced platelet activation as a slight increase in spontaneous platelet aggregation was observed in PRP at the intermediate LDL-concentration. The present findings indicate that low concentrations of LDL stimulate platelet aggregability in the physiological whole blood milieu. This adverse effect of LDL-cholesterol may be of clinical importance in patients with hypercholesterolaemia.     

Clinical usefulness of the measurement of type-II procollagen carboxypeptide (C-II propeptide, pColl-II-C) in synovial fluid as a marker of collagen metabolism in cartilage]

Type-II procollagen-C-peptide (pColl-II-C) in synovial fluids was studied in 319 patients with osteoarthritis (OA; 151), rheumatoid arthritis (RA; 141), traumatic arthritis (TA; 27) and 15 healthy volunteers using the newly developed ELISA kit. The mean levels of pColl-II-C in synovial fluids of healthy controls, OA, TA, and RA were 0.3 +/- 0.1 ng/ml, 5.9 +/- 0.3 ng/ml, 6.8 +/- 1.4 ng/ml and 1.1 +/- 0.1 ng/ml, respectively. pColl-II-C levels in synovial fluids of OA and TA were significantly higher compared to those of healthy controls and RA. It was also demonstrated that pColl-II-C levels could reflect the quantitative and qualitative change of cartilage metabolism. Therefore, the quantification of this molecule in synovial fluid could be beneficial to know the synthetic activity of type II collagen of chondrocytes, since pColl-II-C is a part of the precursor molecule of type II collagen.     

Diarrhea associated with typhoid fever

To study the pathogenesis of diarrhea occurring with typhoid fever, we selected 42 patients with diarrhea and blood cultures positive for Salmonella typhi or Salmonella paratyphi A, but without diarrheal copathogens, for measurement of stool output and examination of fecal composition. The mean duration of fever before hospitalization was 9.5 days, and the mean duration of diarrhea was 5.8 days. All patients passed liquid stool on their first day in the hospital, ranging in volume from 4 to 172 ml/kg with a mean of 45 ml/kg. Red blood cells were in the stools of 57% of the patients. All patients had fecal leukocytes with a mean of 4,950 leukocytes/mm3, predominantly polymorphonuclear leukocytes. In the stools, the mean protein concentration was 9.3 g/liter; the mean pH was 6.1, and the mean concentration of electrolytes was as follows: sodium, 47 mEq/liter; potassium, 48 mEq/liter; and chloride, 43 mEq/liter. The mean total CO2 was 24 mmol/liter. During treatment with chloramphenicol, this group of patients showed daily improvement with a drop in both fever and stool output. The results indicate that patients with diarrhea during typhoid fever have a wide range of rates of purging, and the diarrhea is characterized by liquid stool containing large quantities of leukocytes and protein and is resolved by treatment with chloramphenicol.     

Detection of upper gastrointestinal blood with fecal occult blood tests

OBJECTIVE: Although fecal occult blood (FOB) tests have most often been used to detect occult bleeding from the lower gastrointestinal (GI) tract, their utility in detecting occult blood loss from the upper GI tract is less well understood. The aims of this study were to determine whether small amounts of blood from the upper GI tract can be detected by currently available FOB tests and, if so, to correlate FOB tests with semiquantitative GI blood. METHODS: Groups of 10 healthy volunteers without a history of GI disease drank 5, 10, or 20 ml of their own blood mixed with tomato juice for 5 or 3 consecutive days. Standard dietary and medication restrictions were observed. Consecutive stools were tested for 2 days before, as well as 4 days after, blood ingestion. Each stool was simultaneously tested for FOB with HemoQuant (HQ), Hemoccult II (HO II), Hemoccult II SENSA (SENSA), HemeSelect (HS), and FlexSure OBT (FS). RESULTS: The mean age and hemoglobin concentration of the study population were 29.3+/-0.5 yr and 14.3+/-0.3 g/dl, respectively. No subject noted GI symptoms during blood ingestion. Fecal blood levels (measured by HQ) were elevated within 2 days after initiation of blood ingestion and remained elevated until 2-3 days after cessation of blood ingestion. Mean fecal blood levels peaked at 2.1, 7.9, 8.0, and 13.5 (mg hemoglobin/g stool) in groups ingesting 5 ml/5 days, 10 ml/3 days, 10 ml/5 days, and 20 ml/3 days, respectively. The proportion of positive tests during and immediately after the period of blood ingestion was greatest in the 20 ml/3 day group; 16% of HO II samples were positive as were 64% of SENSA and 67% of HQ samples. SENSA was more sensitive than HO II in all blood ingestion groups. At least one positive SENSA test was present in 50% of subjects ingesting 10 ml of blood (each 3 and 5 day groups) and in all subjects ingesting 20 ml/day. Immunochemical tests did not detect upper GI blood in any blood ingestion group. CONCLUSION: Inasmuch as many upper GI tract lesions have been reported to bleed small quantities of blood such as that studied here, and this amount of blood is readily detected with widely used guaiac-based FOB tests including Hemoccult II SENSA, the data emphasize that caution is warranted before attributing positive guaiac tests only to sites in the lower GI tract. The data raise the possibility that a combination of a highly sensitive guaiac-based FOB test plus an immunochemical could help differentiate occult upper from lower GI bleeding.     

Maintenance of cerebral circulation during hemorrhagic hypotension in newborn pigs: role of prostanoids

The possibility that the prostanoid system contributes to the capability of the newborn piglet to maintain cerebral blood flow and cerebral metabolic rate during hypotension was investigated. The effect of hemorrhage on net (arterial-to-venous) cerebral prostacyclin production and the effects of indomethacin on cerebral hemodynamic response to hemorrhage and on the cerebral oxygen utilization following hemorrhage were determined in chronically instrumented, unanesthetized newborn pigs. Hemorrhage decreased arterial pressure about 35% but did not affect cerebral blood flow or cerebral O2 consumption. Hemorrhage was accompanied by an increase in net cerebral 6-keto-PGF1 alpha production from 4.0 +/- 1.1 to 15.3 +/- 4.9 ng/100g X min (mean +/- SEM). Indomethacin treatment of piglets following hemorrhage inhibited the net cerebral production of 6-keto-PGF1 alpha and caused a decrease in blood flow (approximately equal to 40%) to all brain regions within 20 minutes. The decrease in cerebral blood flow was the result of an increase in cerebral vascular resistance of 57 and 180%, 20 and 40 minutes post treatment, respectively. Cerebral O2 consumption was reduced from 2.5 +/- 0.3 ml/100 g X min to 1.5 +/- 0.3 ml/100 g X min 20 minutes following treatment of hemorrhaged piglets with indomethacin and to 1.1 +/- 0.3 ml/100 g X min 40 minutes after treatment. Six of 8 piglets for whom the data were recorded that were administered indomethacin following hemorrhage became comatose with cerebral O2 consumption of 0.4 +/- 0.1 ml O2/100 g X min by 40 minutes after treatment. These data are consistent with the hypothesis that the prostanoid system contributes to the maintenance of cerebral blood flow and cerebral metabolic rate during hypotension in the newborn.     

Determination of volumes of Trypanosoma vivax and T. congolense separated from cattle blood

Trypanosomes were separated on DEAE cellulose columns from blood samples taken during the first parasitemic wave in T. vivax or T. congolense infected cattle. The mean volume of T. vivax organisms in five steers increased from 16.3 fl SE 0.7 on day five to 20.7 fl SE 0.7 on day eight. Assuming an even distribution of T. vivax throughout the vasculature, the total trypanosome volume at peak parasitemia (36.400 trypanosomes per microliter on day six) was calculated to be about 0.067% of the blood volume, i.e. 8.0 ml. The mean volume of the separated T. congolense organisms was 14.0 fl SE 0.3 on day nine post infection (mean parasitemia of 3.100 trypanosomes per microliter blood). The T. congolense organisms in the jugular venous blood accounted for about 0.0043% of the jugular venous blood volume.     

Investigation of seemingly pathogen-negative diarrhoea in patients infected with HIV1.

Thirty three consecutive patients infected by human immunodeficiency virus type 1 (HIV1) with persistent diarrhoea which remained undiagnosed after microbiological examination of six stool samples and rectal histology were investigated for malabsorption. All had xylose and Schilling tests, distal duodenal biopsy, comprehensive barium studies, microbiological examination of six further stool samples, and repeat rectal histology. A microbiological or histological diagnosis of infection was made in 12 patients (multiple organisms in three). Cryptosporidia were identified on five occasions, cytomegalovirus on four, Giardia lamblia on two, and herpes simplex, Campylobacter jejuni, Salmonella enteritidis, and Entamoeba histolytica once each. No organism was found when weight loss was less than 5 kg or stool volume less than 400 ml/day (n = 9). Pathogens were identified in nine of 13 patients (69%) with weight loss greater than 10 kg and stool volume more than 800 ml/day. Barium studies were normal except for ileal flocculation in two patients with cryptosporidiosis. Evidence for malabsorption existed in 24 patients--impaired xylose absorption (n = 19) and abnormal Schilling test (n = 21). Of the patients with a severely abnormal Schilling test, a pathogen was identified in 11 (79%) (including all five with cryptosporidia, and two of the patients with only moderate diarrhoea and weight loss). A simple scoring system based on degree of weight loss and Schilling test result may help to identify the HIV positive patient with seemingly pathogen-negative diarrhoea in whom further investigations are likely to show a specific cause.     

超声引导下小鼠心脏穿刺取血方法的可行性分析

目的探索超声引导下不开胸进行小鼠心脏精准穿刺取血的方法,以明确该方法所能采集的最大血量,以及是否可以用于长期重复取血。方法将雄性C57BL/6J小鼠(10~14周龄)分为终止性实验组(n=4,检测一次所能取到的最大血量)、反复采血0.5 ml组(n=10,每次取0.5 ml全血,1次/2 d,持续4周),反复采血0.75 ml组(n=10,每次取0.75 ml全血,1次/2 d,持续4周)。使用高频心脏超声显示左心室最大切面,引导胰岛素注射器针头经胸廓进入左心室进行采血。在反复采血0.5 ml组,使用超声检测第一次采血前、第一次采血后3 min、以及采血结束(共采血14次)休息1周后的心脏结构和心功能变化。结果成功施行超声引导下不开胸经心脏穿刺取血,用时(88±19)s/只,获取的最大血量为(1.43±0.11)ml/只。在反复采血0.5 ml组,反复采血4周后,小鼠的心率、左心室射血分数、左心室缩短分数、左心室舒张末期内径及左心室舒张末期后壁厚度与第1次采血前比较,差异无统计学意义(P均>0.05),无小鼠死亡。但在反复采血0.75 ml组,在观察终点前有2只小鼠死亡。结论在超声引导下行小鼠心脏穿刺取血,安全、微创、便捷、高效,可获取血量大,也可用于长期多次取血。     

Atrial natriuretic peptide decreases circulatory capacitance in areflexic rats

The short-term hemodynamic response to atrial natriuretic peptide appears to be partly mediated by decreased venous return, which could result from increased circulatory capacitance or decreased blood volume. To determine if rat atrial natriuretic peptide 99-126 (0.5 microgram/kg/min IV for 30-70 minutes) dilated capacitance vessels or decreased blood volume, mean circulatory filling pressure (measured during brief circulatory arrest by inflating an intraatrial balloon) and blood volume (51Cr-erythrocytes) were measured in anesthetized rats. Mean circulatory filling pressure, central venous pressure, and blood volume decreased by 0.4 mm Hg, 0.5 mm Hg, and 3.4 ml/kg, respectively. To determine the total circulatory pressure-volume relationship without influence from autonomic reflexes, mean circulatory filling pressure and blood volume were measured in spinal-cord-transected rats before and immediately after infusing or withdrawing 5 ml blood. Atrial natriuretic peptide decreased mean circulatory filling pressure, central venous pressure, and blood volume by 0.9 mm Hg, 1.7 mm Hg, and 8.0 ml/kg, respectively, and displaced the pressure-volume relationship toward the pressure axis by decreasing extrapolated unstressed volume. Similar results were obtained in spinal-cord-transected rats that had initial vascular tone restored to a greater level by norepinephrine infusion. In anephric rats, atrial natriuretic peptide decreased central venous pressure by 0.3 mm Hg and blood volume by 1.6 ml/kg. The results indicate that short-term infusion of atrial natriuretic peptide reduced circulatory capacitance in rats and suggest that this reduction resulted from diminished blood volume due to urinary fluid loss followed by passive vascular recoil and active venoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Seroepidemiology of schistosomiasis japonica by ELISA in the Philippines. I. Underestimation by stool examination of the prevalence of infection in school children

In a longitudinal seroepidemiological study in the Schistosoma japonicum endemic area of Leyte, the ELISA technique to determine prevalence and incidence rates in elementary school children was compared with similar determinations made by a modified quantitative stool examination (MIFC). In the area of this study, Barrio Salvador, Tanauan, Leyte, the ongoing schistosomiasis japonica control program in the Philippines is dependent on stool examination by MIFC and/or the quantitative thick smear (Kato-Katz) for measurement of prevalence and incidence. Over a 3-year period with multiple periodic examinations, infection rates were measured and the serologic technique was compared to stool examination in 598 untreated children (mostly 7-10 years of age) of Salvador Elementary School. A group of 150 school children from a non-endemic area, Milagros, Masbate, provided sera as a reference negative control. ELISA results are expressed as ELISA activity (EAc) in reference to a positive control serum pooled from parasitologically confirmed cases, dilutions of which were always included in each assay. A convenient positive-negative discrimination level was chosen based on the EAc values obtained from 170 stool-positive Salvador pupils and the 150 pupils of the non-endemic area. Using the chosen discrimination level, ELISA in this study had a sensitivity of 98% and a specificity of 96%. ELISA was significantly more sensitive than stool examination in detecting infections; only 28% of the children were stool positive on a single examination in contrast with 56% positive by ELISA. A single stool examination underestimated serologic positives by 50% while two stool examinations 4 months apart reduced the underestimate to 29%. The underestimation varied by age and sex, and showed no consistent pattern in this regard. Stool-positive children had a wide variation of egg counts with a geometric mean of 6.4 eggs/g of stool, with 52% of the stool positives excreting only 1-5 eggs/g. A high percentage of infected children have a misdiagnosis of infection by stool examination. This has, in the past, resulted in many being misclassified as noninfected. This erroneous classification has serious consequences on the measurement of prevalence and incidence, on studies of clinical manifestations of the disease, and on the evaluation of serologic techniques for diagnosis. Stool examination does not give an accurate measurement of prevalence, and therefore it cannot be relied upon for the evaluation of the current control program. It is recommended that the capability to undertake serodiagnostic tests for schistosomiasis japonica be encouraged and adopted in the Philippines for field     

Hemoccult detection of fecal occult blood quantitated by radioassay

Results from the guaiac slide or Hemoccult (HO) test for fecal occult blood were compared with quantitative determinations of gastrointestinal loss after intravenous administration of⁵¹Cr-labeled red cells. Subjects were 80 consecutive patients, without dietary restriction, who were referred because of clinical suspicion of gastrointestinal blood loss or complex anemia. A total of 555 stool specimens analyzed for⁵¹Cr loss were graded negative, trace, or positive by the HO method. Of 338 specimens containing 0–2 ml/day by isotope assay, 7.4% were positive to the HO qualitative test. Loss of at least 10 ml/day in⁵¹Cr equivalent was necessary to assure that the majority of HO reactions would be positive. Of specimens containing more than 30 ml/day, 93% were positive. The ratio of⁵¹Cr-labeled red cell equivalents to stool volume and the percentage of positive HO reactions increased together. When this ratio exceeded 10%, two thirds of the HO responses were positive.This investigation was supported in part by Research Grant CB-23854 from the National Cancer Institute, National Institutes of Health, Public Health Service.     

Effects of incremental infusions of atrial natriuretic factor on aldosterone, renin, and blood pressure in humans

To evaluate the physiological effects of human atrial natriuretic factor-(99-126) (ANF), we infused ANF, 0.1, 0.3, and 1.0 micrograms/min, or placebo for 125 minutes on different days into six sodium-deprived normal men. During the last 45 minutes of infusion, angiotensin II, 6 ng/kg/min, was infused. Blood pressure, heart rate, plasma concentrations of ANF, aldosterone, and cortisol, and plasma renin activity (PRA) were measured before and during infusion. Steady state mean plasma ANF levels during infusion were 26.2 (placebo), 68.8 (0.1 micrograms ANF/min), 221 (0.3 micrograms ANF/min), and 648 pg/ml (1.0 microgram ANF/min). Systolic blood pressure fell significantly (with 1.0 microgram ANF/min), and diastolic pressure tended to rise in a dose-dependent manner, while heart rate was unchanged. PRA and plasma aldosterone fell during ANF infusion in a dose-dependent manner (significant with 0.3 and 1.0 microgram ANF/min infused). The blood pressure-raising and aldosterone-stimulating effects of angiotensin II were blunted by ANF (significant only with 1.0 microgram ANF/min). It is concluded that effects of ANF on blood pressure and the renin-aldosterone system occur with plasma ANF levels close to the physiological range, as well as with slightly elevated ANF levels, as observed in congestive heart failure and renal insufficiency.     

Clinical validation of fiberoptic immunobiosensor for point-of-care analysis of plasma nerve growth factor

BACKGROUND: Upregulation of plasma nerve growth factor (NGF) is indicative of cardiac nerve sprouting that is underlying the mechanisms for cardiac arrhythmias. A conventional assay method (e.g., enzyme-linked immunosorbent assay [ELISA]) is usually time consuming and technically complicated for NGF analysis for potential arrhythmia prognosis. OBJECTIVE: This study is to develop a rapid and and reliable assay method for point-of-care (POC) testing of plasma NGF. METHODS: We recently developed a fiberoptic immunobiosensor for point-of-care testing of human plasma NGF. Physiological concentrations of NGF (1 to 200 ng/ml) could be quantified in both buffer and human blood plasma samples (100 microl) within 5 min. The intra-assay coefficient of variation was 5%, and the interassay coefficient of variation was 8%. The clinical utility of the NGF biosensor was evaluated using clinical blood samples from atrial fibrillation patients (n = 21). Peripheral venous blood was sampled before and immediately after radiofrequency ablation and again at postoperative day 1. RESULTS: The NGF level did not change significantly between before (15.73 +/- 16.67 ng/ml) and immediately after radiofrequency ablation (13.58 +/- 11.45 ng/ml, P = NS); however, there was a significant elevation to 28.41 +/- 19.52 ng/ml in postoperative day 1 (P <.01). In a follow-up study (11 +/- 1 months), the increased magnitude in patients with atrial fibrillation recurrence (4.1-fold +/- 1.96-fold) was significantly higher than those without (1.72-fold +/- 0.53-fold; P <.001). The results were highly comparable to those of the ELISA analysis. CONCLUSION: Because of the comparable data accuracy and much faster assay time as compared with ELISA, the fiberoptic biosensor is promising as a clinical POC assay method for plasma NGF analysis at patient bedsides for potential cardiac disease diagnosis and prognosis.     

双抗体夹心斑点酶联法检测轮状病毒的研究

本文报道以本室特制的梳状硝酸纤维素滤膜为载体,采用预先包被特异性抗体的双抗体夹心斑点酶联法检测粪便标本中的轮状病毒。将本法与塑料板 ELISA法(上海市防疫站的试剂盒)对 220例标本检测比较,结果两法符合率为 91.36％,本法阳性率高于板上 ELISA法(P<0.01)。将其中 30份阳性标本进一步作滴度比较,两法相关性好,r=0.8760(P<0.01),本法测得 RV GMT为 119.39,比板上 ELISA法 GMT10.08高 11.8倍,具有显著性差异 P<0.01)。实验还表明本法特异性强、稳定性好、操作简便、结果易于判断。由于预先将抗体包被在梳状膜上(4℃可保存1年),整个检测过程可在二小时之内完成,有助于临床的快速诊断,并易于在基层单位推广应用。     

In vitro culture of erythroid colonies from human fetal liver and umbilical cord blood.

Colony formation by erythroid precursors from human fetal liver, umbilical cord blood and adult peripheral blood has been studied in a plasma clot culture system. Fetal liver (FL) was obtained at post-mortem examination from 13-22 week abortuses. After mincing in Hanks' solution, cells in suspension were harvested by Ficoll-Hypaque centrifugation. Mononuclear cells were obtained by centrifugation of umbilical cord blood (CB) and normal adult peripheral blood (PB). All three types of preparations were incubated up to 14 d in 0.1 ml plasma clot cultures containing 0-4 u/ml erythropoietin (Epo) and 10(6) cells/ml. No colonies formed in the absence of Epo. Normal adult PB produced late-appearing colonies; there were no colonies at day 7 and up to 100 colonies/0.1 ml at day 14. CB produced early and late colonies with up to 200 colonies/0.1 ml at day 7 and 125 at day 14. Cells from FL produced many early colonies; over 1500 colonies/0.1 ml were sent at day 7 and there was a subsequent decline in colony count with longer incubation. In cultures of both CB and FL, colonies composed of either mature or immature cells were noted during both early and late stages of incubation suggesting that these cell sources contain a heterogeneous population of erythroid colony progenitors. Measurement of differential beta and gamma globin chain synthesis by erythroid colonies grown from fetal liver and umbilical cord blood gave results similar to those obtained by direct pulse-labelling of the original source of the cultured cells.     

125I]hGH metabolism in acromegaly: effects of chronic treatment with 2-Br-alpha-ergocryptine.

To assess the effects of 2-Br-alpha-ergocryptine (CB-154 Sandoz) on hGH metabolism, six acromegalic women were studied before and after 2 months of treatment with 10 mg bromocriptine/day. GH kinetics were evaluated by noncompartmental analysis of the plasma disappearance curve of immunoprecipitable [125I]human GH after pulse administration of the labeled hormone. MCR was increased in all acromegalics after treatment; the difference between the means [153 +/- 11 vs. 200 +/- 16 ml/min . m2 (mean +/- SE)] was highly significant. Secretion rate (SR), measured as the product of MCR by integrated 12-h concentration, was decreased in four patients after treatment, while it was slightly increased in the other two. No change was found after treatment, either initial distribution volume [2.0 +/-0.1 before (B) vs. 2.1 +/- 0.1 liters/m2 after (A)] or total distribution volume [5.0 +/- 0.3 (B) vs. 5.4 +/- 0.4 liters/m2 (A)]. Diffusion of GH from the intravascular pool, measured as reentry rate, was unchanged with treatment [66 +/- 4 (B) vs. 76 +/- 11 ml/min . m2 (A)]. In conclusion, our study shows that in acromegaly, by increasing the MCR of the hormone, and 2) by reducing the SR. The mechanisms by which bromocriptine increased MCR of the GH are also suggested on the basis of kinetic results; like dopamine, bromocriptine could induce a redistribution of blood flows to different organs, thus resulting in a net increase of blood flow to the liver and kidneys which are the major catabolic sites of GH.     

Effect of Posture on the Plasma Levels of Atrial Natriuretic Factor

Atrial natriuretic factor (ANF) is a peptide with potent natriuretic, diuretic and vasorelaxant activities. Stretching of the right atria causes release of ANF into the circulation. Therefore, changes in central blood volume or acute volume expansion are likely to change the plasma levels of ANF. In this study we investigated the effects of changes in posture on the plasma levels of ANF, plasma renin activity (PRA) and plasma aldosterone (aldo). Eight male and five female volunteers ranging in age from 23 to 26 years were placed on a normal sodium intake and on the experimental day blood was obtained for ANF, PRA, and aldo after 30 minutes of lying supine, 30 minutes of 10 or 20 degrees head-down tilt, and 30 minutes of standing. Plasma ANF increased significantly after 30 minutes of head-down tilt from the supine value of 33.7 ± 5.2 pg/ml to 47.7 ± 7.7 pg/ml (p<0.02) and suppressed to 14.1 ± 0.02) after 30 minutes of standing. PRA did not change significantly with head-down tilt, (supine 1.64 ± 0.44 ngAI/ml/h vs. 30 minutes tilt 1.28 ± 0.32 ngAI/ml/h (p = NS). Plasma aldosterone decreased by head-down tilt from 11.2 ± 1.2 ng/ml to 8.4 ± 0.8 ng/dl (p<0.02) and returned to the supine level after standing. In conclusion ANF levels change significantly with posture. Increase in central blood volume by head-down tilt increases ANF levels and suppresses plasma aldosterone with no effect on PRA. Standing decreases ANF significantly. These results suggest that for proper interpretation of plasma levels of ANF, posture at the time of sampling has to be standardized.     

Di-2–ethylhexylphthalate (DEHP) Content of Blood or Blood Components Stored in Plastic Bags

Di-2-ethylhexylphthalate (DEHP) is a plasticizer used in the manufacture of plastic bags for blood products, which may be toxic. No more than a trace (less than 0.1 microgram/ml) could be detected in anticoagulants in blood bags, or in the blood of healthy untransfused subjects. A mean of 23 microgram/ml was found in ACD whole blood after 2 weeks storage, and 46 microgram/ml after 3 weeks; the corresponding figures for packed cells were 39 and 45 microgram/ml. The level in CPD whole blood was similar. Fresh frozen plasma and cryoprecipitate contained 7 microgram/ml, while levels of 1.0 and 0.7 microgram/ml of DEHP were found in the blood of two patients who had received massive transfusions. Most DEHP in stored blood was associated with plasma lipoproteins.