Functional capacity of transfused platelets estimated by the Thrombostat 4000/2

Post-transfusion platelet increment is a useful test for the evaluation of transfusion efficacy. It does not, however, give information about the in vivo platelet function. We have evaluated the in vitro bleeding time (IVBT) using the Thrombostat 4000/2 with ADP as activating agent in 60 platelet transfusions given to 17 chemotherapy-induced severely thrombocytopenic patients. Determinations were performed before and after transfusion of platelet concentrates (PC) prepared from buffy coat. Both fresh and stored platelets resulted in significant reductions of the IVBT already 10 minutes after completed platelet transfusion. In the majority of patients there was a correspondence between IVBT and platelet increment. However, in 30% of the cases there was no improvement of the IVBT despite an increase of the platelet count. Fresh PCs were more effective than stored. The IVBT seems to represent a clear-cut improvement in the possibilities for evaluating and monitoring the effect of platelet transfusion.

[The prognostic value of different patterns of change in the CD4 lymphocyte counts in 420 symptom-free HIV-1-infected persons]

The pattern of change over time of CD4-lymphocyte counts was investigated prospectively in 420 patients infected with HIV-1 (106 women, 314 men; mean age 34.9 [21-70] years) to assess its value in prognosticating progression to AIDS. Only those CD4-lymphocyte values were taken into account which had been measured in the asymptomatic stage of the HIV infection and before introduction of antiviral treatment. An average of 4.5 (range 3-10) measurements per person were available. Mean observation time was 2.4 years, the mean annual CD4-lymphocyte decrease was 48 cells/microliters. 121 patients (28.8%) had a fall in CD4-lymphocyte count which in the regression analysis significantly differed from zero. In this group there occurred 19 progressions to AIDS (15.7%), in contrast to only 20 (6.6%) in the 299 patients with a nonsignificant CD4 fall (P < 0.01). Multivariate analysis with the Cox regression indicated that the annual reduction in the CD4 count and the initial CD4 count were the only values of prognostic significance regarding progression to AIDS. There was no evidence that percentage and absolute CD4-lymphocyte counts had a different predictive value. When the initial CD4 count was high (> 900 cells/microliters), there was on average a steeper reduction in CD4-lymphocyte counts than when it was lower. This findings argues against a linear CD4 fall during the total period of observation. The annual CD4 fall, described with linear regression, is a prognostic criterion on its own for early recognition of those patients at a high risk of progression to AIDS while still in the asymptomatic stage of HIV infection.

Lactation affects pressor, volumetric and natriuretic responses to angiotensin II in goats

Demands on cardiovascular function and fluid turnover increase during lactation and pregnancy in the goat, but the hormonal status is different. This study is aimed at investigating the effects of hypertensive angiotensin II (ANGII) in lactating goats. The results were compared with those of pregnancy and control conditions. ANGII (0.5 microgram min-1) was infused intravenously for 60 min (n = 6). The rise in blood pressure in response to ANGII was attenuated during lactation as in pregnancy (P < 0.001 vs control period). ANGII caused reflex bradycardia. Plasma protein concentration decreased by 7.5% during infusions in lactating goats (pregnancy: 9%; control period: 4.5%). Renal Na excretion increased by 260% (lactation), by 400% (pregnancy; n.s. vs. lactation), and by 800% (control period; P < 0.01 vs. lactation). The glomerular filtration rate was unchanged during ANGII infusions in lactating animals, but increased in the other periods. Effective renal plasma flow decreased. ANGII raised aldosterone from < 34.5 pmol l-1 to 539 +/- 80 pmol l-1 (lactation) and to 428 +/- 41 pmol l-1 (control; P < 0.05 vs. lactation), and from 72 +/- 9 to 651 +/- 103 pmol l-1 (pregnancy; P < 0.01 vs. lactation). Plasma progesterone was undetectable during lactation, but varied from 0 to 17 nmol l-1 during control conditions and was 16 +/- 1 nmol l-1 during pregnancy. Oestradiol 17 beta was 181 +/- 22 pmol l-1 in pregnant goats, and undetectable in lactating animals. In conclusion, lactation affects ANGII-induced changes in cardiovascular and fluid regulation, but in this period the effects were not related to progesterone or oestradiol 17 beta.

The effect of biliary decompression on bacterial translocation in jaundiced rats

Patients with obstructive jaundice are prone to septic complications after biliary tract operations. Restoring bile flow to the intestine may help to decrease the complication rate. The present study is aimed at evaluating the effect of biliary decompression on bacterial translocation in jaundiced rats. Sixty-six male Sprague-Dawley rats were randomly allocated to six groups subjected to common bile duct ligation (CBDL) and transection (groups 2-6) or sham operation (group 1). In groups 1 and 2 the incidence of enteric bacterial translocation was determined 2 weeks after sham operation or CBDL. In groups 3-6, biliary decompression was achieved by performing a choledochoduodenostomy after 2 weeks of biliary decompression. Bacterial translocation was then studied 1, 2, 3 and 5 weeks following biliary decompression. The rate of bacterial translocation to mesenteric lymph nodes in obstructive jaundice was significantly higher as compared with controls and decreased with time to nil three weeks following biliary decompression. The incidence of bacterial translocation was closely correlated (r = 0.844; p = 0.034) with serum alkaline phosphatase activity and seemed to fit with the morphological changes noted in the small intestine. The decrease in bacterial translocation, however, lags behind the recovery of liver function as measured by routine liver function tests and antipyrine clearance. Obstructive jaundice thus promotes bacterial translocation in the rat. Biliary decompression gradually decreases the rate of bacterial translocation.

Atrial natriuretic peptide attenuates pressor but enhances natriuretic responses to angiotensin II in pregnant conscious goats

This study was designed to examine the actions of ANP in acute, ANGII-mediated hypertension during pregnancy. Effects on blood pressure, blood volume, and renal Na and K excretion were evaluated in conscious goats (n = 6). ANP (2 micrograms min-1), ANGII (0.5 microgram min-1), or ANGII+ANP (doses the same as for each peptide alone) was infused intravenously for 60 min. The pressor response to ANGII was reduced in pregnant goats. This reduction was seen in systolic, but not in diastolic pressure. ANP decreased pressure by 5-10 mmHg both in pregnancy and in non-pregnancy. When ANGII+ANP was infused, blood pressure initially rose as with ANGII but then declined. ANP suppressed only the elevated systolic pressure. Plasma protein concentration and haematocrit was reduced by ANGII but increased by ANP alone or together with ANGII, thereby implying fluid shift into the vasculature by ANGII and opposite movement by ANP. ANGII increased renal Na excretion to 1500 mumol min-1 in non-pregnancy, but only to half of that in pregnancy. ANP alone caused small natriuresis, but enhanced ANGII-induced natriuresis to near 3000 mumol min-1 in both non-pregnant and pregnant goats. In summary, ANP further attenuated the blunted blood-pressure rise due to ANGII in pregnant goats, and reduced plasma volume, but enhanced renal Na excretion as in non-pregnant goats. This implies that with the present combination ANP and ANGII caused a near maximal natriuretic response that was not modified by the systemic cardiovascular changes occurring in pregnant goats.

Formation of heterocyclic amines using model systems

Initially, modeling was used to identify the mutagenic heterocyclic amines and their precursors. Major precursors have been shown to be single amino acids or amino acids together with creatine or creatinine. There is also evidence that Maillard reactions are involved since heating sugar and amino acids together with creatine or creatinine has been shown to produce several of the mutagenic heterocyclic amines, especially the aminoimidazoazaarenes (AIA compounds), e.g., IQ, MeIQ, MeIQx, DiMeIQx and PhIP. Due to a low yield in the model systems, the mechanisms behind the formation of the mutagenic heterocyclic amines are still unclear and need further substantiation. The fact that some AIA compounds are also produced in the absence of sugar casts some doubts on an obligatory participation of the Maillard reaction; alternative routes might exist. Further work using isotopically labeled precursors needs to be done and so far such work has only been performed for PhiP. The formation of mutagenic heterocyclic amines is dependent on time, temperature, pH, concentration of the precursors, type of amino acid, and the presence of certain divalent ions. Water may have an impact both as a temperature regulator and as a solvent medium for the reactants.

Plasmid-identified Staphylococcus saprophyticus isolated from the rectum of patients with urinary tract infections

Among 15 strains of Staphylococcus saprophyticus of various origin, 13 presented different plasmid patterns, making plasmid identification a useful epidemiological marker. In a consecutive study of 14 young female patients with urinary tract infection caused by S. saprophyticus, 6 patients were simultaneously positive for the same bacterium in the stools. Three paired samples contained the identical plasmid-identified clone of S. saprophyticus indicating that the rectum may be a reservoir of this urinary pathogen.

Staphylococcus saprophyticus found to be a common contaminant of food

The mode of transmission of Staphylococcus saprophyticus, a urinary tract pathogen, was investigated in three related studies. The presence of this organism was sought, during a period of 1 year, in 1331 specimens of various foods, in 920 beef and pork carcasses and on 107 cultures which had been inoculated directly from abattoir workers' protective gloves. Staphylococcus saprophyticus was found to contaminate 16.4% of the various food samples with a high prevalence of 34% in raw beef and pork. It was common in both domestic and imported raw meat products. There was no seasonal variation in the presence of S. saprophyticus in the samples obtained from carcasses. The bacterium was found in 69% of all cultures from the workers' protective gloves. We conclude that S. saprophyticus, originating from slaughtered animals, contaminates food and eventually colonizes the human intestinal tract.

Regional changes in sympathetic nerve activity and baroreceptor reflex function and arterial plasma levels of catecholamines, renin and vasopressin during naloxone-precipitated morphine withdrawal in rats

The aim of the study was to examine regional changes in sympathetic nerve activity (SNA) and baroreceptor function and arterial plasma catecholamines, arginine vasopressin (AVP) and plasma renin activity during morphine withdrawal in chloralose-anesthetized rats. Dependence was induced by s.c. morphine base pellets. Adrenal, renal and splanchnic SNA and SNA from the lumbar sympathetic chain were recorded before and after i.v. injections of naloxone. Baroreceptor function was examined with phenylephrine-induced increases in mean arterial pressure. In separate experiments, arterial plasma norepinephrine, epinephrine, dopamine, plasma renin activity and AVP were measured before and after naloxone-precipitated withdrawal. Naloxone administration elicited an increase in mean arterial pressure and heart rate. Although renal SNA was inhibited by approximately 50%, adrenal SNA and lumbar SNA increased by approximately 400 and 80%, respectively. Splanchnic SNA did not change significantly. The baroreceptor-mediated inhibition of adrenal SNA was facilitated while that for renal SNA was attenuated. The arterial plasma level of norepinephrine was doubled and epinephrine increased almost 20-fold. AVP increased about 15-fold, whereas plasma renin activity showed only a minor increase after naloxone. This study shows that a marked differentiation of the SNA response occurs during morphine withdrawal in rats, which suggests an interaction between opioid receptors and the control of regional sympathetic output. Furthermore, large amounts of AVP and epinephrine are released, which probably contribute to the cardiovascular changes seen in the withdrawal phase.

Fluid balance and arterial blood pressure during intracarotid infusions of atrial natriuretic peptide (ANP) in water-deprived goats

The aim of this study was to investigate if atrial natriuretic peptide (ANP) plays a role in the control of water balance in goats and whether ANP affects the increase in mean arterial blood pressure (MAP) which accompanies drinking in water-deprived animals. Bilateral intracarotid infusions were made in female adult goats deprived of water for 48 h. ANP (1.5 micrograms min-1, n = 5, or 4.75 micrograms min-1, n = 5) was infused for 40 min. In control experiments isotonic saline (n = 7) was infused. The goats got access to water 35 min after the start of the infusions. During saline infusions they drank 2.9 +/- 0.4 litres, during the low dose of ANP 1.9 +/- 0.6 litres (n.s. vs saline), and during the high dose of ANP 0.6 +/- 0.2 litres (P less than 0.01 vs saline). Plasma vasopressin concentration did not change during saline infusions until after drinking, when it decreased. The vasopressin concentration increased in one goat after infusion of the low dose of ANP and in two goats after the high dose of ANP. The low dose of ANP caused no change in MAP in four goats, but MAP dropped in the one in which vasopressin concentration increased. MAP fell in all goats infused with the high dose (P less than 0.01), with the largest changes occurring in animals showing increased vasopressin concentration. During the act of drinking a temporary increase of MAP was observed when saline or the low dose of ANP was infused, but this response was attenuated during infusions of the high dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluid balance during heat stress in lactating goats

Fluid balance and thermoregulation were studied during an acute heat load (maximal daily temperature, 38 +/- 1 degrees C; night temperature 27 +/- 1 degrees C) in six goats during lactation and non-lactation. The goats had free access to water for 1 day, followed by 29.5 h of water deprivation and then water was returned. With water available the goats increased water intake and urinary and milk water losses, while plasma and milk osmolality decreased. Water deprivation caused plasma osmolality and vasopressin concentration to increase most in lactating goats. Milk osmolality rose to values similar to plasma osmolality. Plasma cortisol increased in lactating goats at the end of dehydration. Renal Na+ excretion increased during dehydration in lactating goats. Evaporative heat loss was larger in lactating goats when hydrated, but became less than in non-lactating goats during dehydration. Lactating goats exhibited higher respiratory frequency and rectal temperature than non-lactating goats. In conclusion, our results show that goats increase the water turnover during heat stress if allowed to drink ad libitum, but when they are deprived of water lactating goats reduce water loss in urine, milk and by evaporation, and rectal temperature reaches higher levels than in non-lactating animals. This saving of water could allow milk production to be maintained for a longer time during heat stress.

Atrial natriuretic peptide in pregnant and lactating goats

Plasma concentrations of atrial natriuretic peptide (ANP) were measured in 6 goats during pregnancy, lactation and a nonpregnant, nonlactating (= control) period before and during a rapid iv load of 0.9% NaCl. The volume of the load was 20% of blood volume. The infusions increased central venous pressure by 7 +/- 1 mmHg during pregnancy and 8 +/- 1 mmHg during lactation. Before infusions plasma ANP concentrations were 5.7 +/- 0.7 pmol/l (control period), 10.8 +/- 1.8 pmol/l (pregnancy; P less than 0.05), and 6.5 +/- 1.5 pmol/l (lactation; NS). ANP increased significantly in all periods. Maximal values were 12.5 +/- 1.5 (control period), 25.5 +/- 2.3 (pregnancy; P less than 0.01 vs control period, P less than 0.05 vs lactation), and 13.0 +/- 1.6 (lactation; NS). Renal Na excretion increased similarly during pregnancy and control period, but slightly more during lactation. In 4 of the goats iv infusions of ANP (1 microgram/min, 60 min) were given. The infusions caused natriuresis during the control period, but not during pregnancy and lactation, despite more than 10-fold increases of plasma ANP levels. In conclusion, our results indicate that although plasma ANP concentration rose to high levels during acute NaCl loading in pregnant goats, this effect was not important for the natriuresis. Instead, the natriuretic response to ANP appears attenuated during pregnancy, and also during lactation.