T lymphocyte activation is associated with viral replication in chronic hepatitis B virus infection of childhood.

Activated circulating T lymphocytes expressing HLA-DR (mean +/- s.d. 11.0 +/- 5.2%) or interleukin-2 receptor (IL-2R) (2.1 +/- 1.7%) were significantly increased in 63 children with chronic hepatitis B virus (HBV) infection when compared with 33 age-matched healthy controls (3.0 +/- 1.3%, P less than 0.01, and 0.1 +/- 0.4%, P less than 0.01). HBeAg-positive patients had higher percentage of DR (11.9 +/- 5.1%) or IL-2R (2.4 +/- 1.7%) positive T lymphocytes than anti-HBe-positive children (7.4 +/- 3.6% and 1.1 +/- 1.5%, P less than 0.01 and P = 0.02 respectively). Similarly, HBV DNA-positive patients had higher percentage of DR (10.5 +/- 3.3) or IL-2R (3.2 +/- 1.7%) positive T cells than HBV DNA-negative children (6.6 +/- 2.8% and 1.2 +/- 1.5%, P less than 0.01 for both). There was a positive correlation between percentage of DR positive T lymphocytes and levels of HBV DNA. Sixty-two per cent of the DR-positive T lymphocytes were cytotoxic/suppressor and 35% helper/inducer. The relationship between viral replication and T lymphocyte activation is discussed.     

Rose bengal score--a possible key parameter when evaluating disease level and progression in primary Sj?gren's syndrome

The rose bengal score is one of the most commonly used tests for evaluation of ocular surface epithelial damage. The test is used in most Sj?gren's syndrome criteria. We examined 24 female and four male patients with primary Sj?gren's syndrome (primary SS) in order to evaluate possible correlation between the various tests for keratoconjuncivitis sicca (KCS), and for possible correlations to xerostomia and p-IgG levels. Among the KCS tests a high rose bengal score appeared to be the key parameter, being correlated to low break-up time (P less than 0.01), low tear lysozyme (P less than 0.01), appearance of snake-like chromatin in conjunctival imprints (P less than 0.05), low sialometry (P greater than 0.01) and high p-IgG (P less than 0.01). We followed another group of patients with primary SS (30 females and four males) for a mean period of 53 (range 27-76) months. The patients were divided according to their initial response to systemic treatment with bromhexine. KCS parametres and p-IgG were measured repeatedly during the observation period. Patients responding to and continuously treated with bromhexine (2/3 of patients) improved significantly (P less than 0.05) in rose bengal score, but had increasing levels of p-IgG. Non-responders kept their low tear-production rate and had also increasing p-IgG levels. However, when subdivided according to p-IgG level, the group of patients with relatively low p-IgG improved in rose begal score, whereas the high p-IgG-group increased in rose bengal score. The rose bengal score appears to be a useful key parameter when evaluating disease level and progression.     

Renal hemodynamics in conscious rats: effects of anesthesia, surgery, and recovery

The influence of barbiturate anesthesia and minor surgical incisions on renal function was assessed in trained, chronically catheterized rats. In addition, renal hemodynamic changes during recovery from ether anesthesia and surgery were examined. Administration of pentobarbital in the chronic animals was associated with a marked reduction in arterial pressure (108 +/- 5 vs. 85 +/- 2 mmHg, P less than 0.01), renal blood flow (8.28 +/- 0.50 vs. 6.20 +/- 0.53 ml X min-1 X 100 g body wt-1, P less than 0.01), and glomerular filtration rate (1.30 +/- 0.10 vs. 0.97 +/- 0.11 ml X min-1 X 100 g body wt-1, P less than 0.01). Responses to Inactin were essentially identical. Small skin incisions during barbiturate anesthesia caused blood pressure to rise, but did not significantly change renal function parameters from already reduced values. In rats studied 2 h after ether anesthesia and surgical placement of catheters, arterial pressure was elevated compared with the same rats studied 4-7 days later (127 +/- 3 vs. 109 +/- 3 mmHg, P less than 0.005). Renal blood flow (5.80 +/- 0.37 vs. 8.90 +/- 0.93 ml X min-1 X 100 g body wt-1, P less than 0.01) and glomerular filtration rate (0.81 +/- 0.07 vs. 1.05 +/- 0.08 ml X min-1 X 100 g body wt-1, P less than 0.001) were markedly depressed during the recovery from surgery. It is concluded that barbiturate anesthesia depresses renal function in rats. This impairment should be considered when interpreting experiments that must be performed under anesthesia. In addition, the "conscious" preparation commonly used for renal studies in rats, i.e., one involving experimentation 2-3 h after ether anesthesia and surgery, is associated with a severe depression of renal hemodynamics.     

Ineffective ventilation during exercise in patients with chronic congestive heart failure.

The pathophysiologic mechanisms causing exertional breathlessness in patients with chronic congestive heart failure (CHF) are not fully understood. Therefore, we have studied whether the ventilation in such patients is ineffective during exercise. Thirteen patients with treated chronic CHF (New York Heart Association class II-IV) and eight healthy controls underwent a maximal bicycle ergometer test with continuous analysis of expired air and frequent arterial blood sampling for gas and lactate analysis. All subjects were non-smokers and none had any signs of a pulmonary disease. Peak O2 consumption of the patients was 14.9 +/- 5.3 ml min-1 kg-1 and that of controls 33.6 +/- 7.5 ml min-1 kg-1. In patients with CHF the ratio of pulmonary dead space to tidal volume was significantly elevated at peak exercise compared with that of the controls (0.36 +/- 0.08 vs. 0.20 +/- 0.07, P less than 0.05). The ventilatory equivalent for CO2 (VE:VCO2) was also significantly higher in patients than in controls during exercise (P less than 0.05). Furthermore, both the ventilatory equivalents for CO2 and O2 (VE:VO2) had a significant inverse correlation with peak O2 consumption (P less than 0.001 for VE:VCO2 and P less than 0.05 for VE:VO2), O2 consumption at anaerobic threshold (P less than 0.01) and O2-pulse (P less than 0.001) among the patients. During exercise the arterial PO2 and PCO2 remained normal in patients and controls. These data indicate that in patients with chronic CHF wasted ventilation is pathologically increased during exercise, and this is related to the severity of the disease. Chronic CHF is not associated with decreased ventilatory reserve, hypoxaemia or alveolar hyperventilation. The ineffectiveness of ventilation is probably an important cause of exertional breathlessness in patients with CHF.     

Effects of adenosine on autonomic control of heart rate in man

Six healthy subjects (two female) aged 23-40 years participated in a double-blind randomized cross-over study to investigate autonomic mechanisms involved in the chronotropic effect of adenosine in conscious man. Adenosine was infused in increasing doses following saline, propranolol (0.2 mg kg-1 body weight) or propranolol (0.2 mg kg-1 plus atropine (0.04 mg kg-1). Heart rate and blood pressure were measured supine, on standing and during a Valsalva manoeuvre. Plasma catecholamines were measured in the supine and standing positions. Following saline, adenosine (up to 120 micrograms kg-1 min-1) caused a dose-related increase in heart rate (mean +/- SD maximum increase 18 +/- 8 bpm; P less than 0.01). The change in heart rate with adenosine after propranolol (12 +/- 9 bpm; P less than 0.05) did not differ significantly from the corresponding change following saline but was abolished by propranolol plus atropine, which, in turn, was associated with a mean maximum decrease in heart rate of 5 +/- 3 bpm (P less than 0.01). The increase in heart rate during the initial 30 s on standing was augmented with adenosine compared with saline (16 +/- 5 bpm; P less than 0.01). A significant increase in plasma noradrenaline on standing was also found with adenosine compared with saline (6.37 +/- 2.86 vs. 4.77 +/- 1.79 nmol 1(-1); P less than 0.05). The heart rate response to the Valsalva manoeuvre was not affected by adenosine. These results suggest that the positive chronotropic effect of infused adenosine in conscious man may in part be caused by an inhibition of cardiac vagal tone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modulatory role of gamma-aminobutyric acid (GABA) in the regulation of gonadotropin secretion in patients with chronic renal failure

The role of gamma-aminobutyric acid (GABA) in the regulation of gonadotropin secretion in renal failure, was studied in 5 patients with chronic renal failure who were on maintenance dialysis. Di-n-propylacetic acid (valproic acid-VA), a GABA-transaminase inhibitor which has been shown to increase brain GABA levels, was used in the study. VA produced no significant change in the basal serum LH and FSH concentrations, or in E2 or T concentrations in the renal failure patients, or the E2 and P concentrations in normal controls, but augmented the delta LH (maximum increment above baseline) and delta FSH response to LH-RH. delta LH rose from 30.4 +/- 12.7 mIU/ml (mean +/- SD) to 41.1 +/- 16.8 mIU/ml (p less than 0.01) after VA, while delta FSH rose from 2.8 +/- 1.8 mIU/ml to 3.8 +/- 1.6 mIU/ml (p less than 0.05). The findings support a modulatory role for GABA in gonadotropin secretion in chronic renal failure.     

Low bone mass in hypogonadal males. Effect of testosterone substitution therapy, a densitometric study.

Sixteen (16) male patients who were suffering from hypogonadism but who were free from bone symptoms were recruited from the Andrology Clinic. Their bone mineral density (BMD) was assessed by single photon absorptiometry in the non-dominant radius, at both the distal radius (DR) (27% trabecular bone) and the midshaft radius (MR) (90% cortical bone). Measurements were carried out before and during testosterone substitution therapy. BMD was found to be lower in the subjects than in the controls, to a similar extent at both the DR (0.47 +/- 0.02 g/cm2, i.e. 83.1 +/- 4.3% of the value in the controls, or Z score -1.42 +/- 0.39; P less than 0.01) and the MR (0.68 +/- 0.02 g/cm2, i.e. 87.8 +/- 2.4% of the value in the controls, or Z score -1.49 +/- 0.33; P less than 0.01). There was no correlation between testosterone levels and BMD at either the DR or the MR at the beginning of the study. Following testosterone substitution therapy, bone mineral content (BMC) increased significantly at the DR (+5.9 +/- 1.4% per year; P less than 0.01) and at the MR (+1.1 +/- 0.9% per year; P less than 0.01). If the study is limited to the subjects who had achieved full bone age maturity before the start of therapy, the bone gain remains significant only at the DR, a site with a sizeable proportion of trabecular bone.     

Influence of serotonin on total intravascular capacity in the anaesthetized dog

The influence of serotonin on intravascular volume in the total capacitance circulation has not previously been examined. Thus, blood was drained from the venae cavae to an extracorporeal reservoir and returned to the right atrium at a constant rate so that total intravascular volume changes could be recorded as the inverse of changes in reservoir volume in 31 anaesthetized dogs. Serotonin (588 +/- 47 micrograms) in the left atrium was associated with an initial decrease in intravascular volume of 39 +/- 12 ml (P less than 0.01) followed by an increase of 129 +/- 31 ml (P less than 0.01) above control at 20 min. Mean arterial pressure increased from a control of 74 +/- 4 mmHg to 99 +/- 7 mmHg (P less than 0.01) initially and then decreased to 64 +/- 5 mmHg (P less than 0.05) at 20 min. Following ganglionic blockade with mecamylamine, serotonin caused only a decrease in intravascular volume, which was 73 +/- 12 ml (P less than 0.01) at 20 min. 5-HT2 and alpha-adrenergic blockade with ketanserin did not attenuate the early decrease in intravascular volume. 5-Carboxamidotryptamine (82 +/- 39 micrograms), a 5-HT1 agonist, was associated with only an increase in intravascular volume, which was 82 +/- 13 ml (P less than 0.01) at 20 min and which was abolished after ganglionic blockade. Thus, serotonin causes a biphasic change in total intravascular volume. The initial decrease in intravascular volume is not mediated by a reflex or by 5-HT1, 5-HT2, or alpha-adrenergic receptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypovitaminosis D in children with type 1 diabetes mellitus and its influence on biochemical and densitometric parameters

The aim of the study was to establish the frequency of hypovitaminosis D in children with type 1 diabetes mellitus (T1D), its influence on biochemical and densitometric parameters and the relation to diabetic nephropathy. 58 children with T1D at the age 9-19 years were enrolled to the study. Vitamin D concentration less than 30 ng/ml was considered as insufficient. 37 children (63.79%) had vitamin D level under 30 ng/ml, from these 19 subjects (32.7%) had vitamin D level under 20 ng/ml and 2 subjects (3.44%) under 10 ng/ml. Children with vitamin D deficiency had significantly lower magnesium concentration and lower Z score of lumbar spine (-1.34 +/- 1.24 vs. -.030 +/- 1.21, p = 0.01) compared to diabetics with sufficient vitamin D concentration. No significant difference was found in parameters calcium, phosphorus or glycosylated hemoglobin. Patients with diabetic nephropathy (n = 18) showed no significant difference in vitamin D, glycosylated hemoglobin or Z score of lumbar spine compared to the patients without nephropathy (n = 40). Subjects with nephropathy had significantly longer diabetes duration, significantly higher cholesterol and triacylglycerol concentration. In our cohort of patients nearly two thirds of children had insufficient vitamin D concentration what supports the need to monitor and eventually supplement vitamin D in T1D subjects.     

Preferential activation of helper/inducer T lymphocytes in autoimmune chronic active hepatitis.

We found a significant increase of activated circulating T lymphocytes expressing interleukin 2 receptor (IL-2r) (mean +/- s.e.m. 11.0 +/- 1.1%) or DR antigen (5.0 +/- 0.49%) in patients with autoimmune chronic active hepatitis (CAH) starting in childhood when compared to healthy controls (0.14 +/- 0.09%, P less than 0.001 and 2.8 +/- 0.06%, P less than 0.01). Patients with liver disorders due to Wilson's disease (IL-2r 0.64 +/- 0.25%, DR 3.5 +/- 0.22%) or alpha-1-antitrypsin deficiency (IL-2r 0.1 +/- 0.06%, DR 2.8 +/- 0.35%) had levels similar to controls. Levels of both IL-2r and DR positive T lymphocytes were higher in patients with uncontrolled CAH (IL-2r 18.0 +/- 1.01%; DR 6.3 +/- 0.78%) than in patients with inactive disease (IL-2r 3.2 +/- 1.4%, P less than 0.001; DR 3.0 +/- 0.13%, P less than 0.01). In patients with active disease levels of IL-2r positive cells were higher than DR positive cells (P less than 0.001). Only 21% of activated T cells coexpressed the two markers of activation. Sixty-seven percent of IL-2r positive T lymphocytes were helper/inducer and 25% suppressor/cytotoxic, while 66% of the DR positive T cells were suppressor/cytotoxic and 31% helper/inducer. The finding that the highest levels of activated T lymphocytes are present in patients with uncontrolled CAH suggests that these cells are involved in its pathogenesis. The preferential increase of activated helper/inducer cells might explain the enhanced immune reactivity characteristic of autoimmune CAH.     

Comparative auto-controlled study between swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization.

This study compared swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization. Sixty trials of in-vitro fertilization (IVF), 38 with normal semen and 22 with abnormal semen, comprising 734 oocytes were included in the study. Each semen sample was prepared by both a swim-up technique and a simplified discontinuous (50%, 70%, 90%) Percoll gradient. The oocytes for each trial were distributed at random between the two sperm preparations and incubated with the same number of motile spermatozoa. Percoll gradient preparation produced a significantly higher final concentration of spermatozoa than swim-up preparation (mean +/- SEM: 6.6 +/- 1.5 x 10(6)/ml versus 1.9 +/- 0.2 x 10(6)/ml; P less than 0.01) but a significantly lower sperm motility (69 +/- 2% versus 94 +/- 1%; P less than 0.001) and a lower number of normal forms (55 +/- 2% versus 64 +/- 2%; P less than 0.01). The ability of the Percoll gradient method to extract motile spermatozoa was higher than that of the swim-up technique (20 +/- 15.6% versus 0.8 +/- 13.6%). Nevertheless, the rates of fertilization (61%), fertilization failure (18%) and polyspermia (9%), embryo quality evaluated by mean embryo scores (3.8 +/- 0.3) and the mean number of spare embryos frozen per trial (1.4 +/- 0.3) were strictly identical in both groups. The 24 pregnancies (including three from frozen--thawed embryos) obtained in these 60 trials (40% per oocyte retrieval) could not be separated according to the sperm preparation method, as embryos from both groups were replaced together.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of hypertonic intracarotid infusions on plasma vasopressin concentration

The effect of short-term bilateral intracarotid infusions of hypertonic saline on plasma vasopressin concentration (pAVP) was evaluated in five dogs. Intracarotid infusion of saline at 90 mumol . kg-1 . min-1 . artery-1 significantly (P less than 0.05) increased jugular vein osmolality (pOsm) and sodium concentration (pNa+) within 2 min. Saphenous vein pOsm was not altered during the 6 min of infusion, whereas pNa+ was increased (P less than 0.05) from 0.8 +/- 0.1 to 2.3 +/- 0.3 pg/ml. Subsequent experiments using hypertonic saline infusions of 90 and 180 mumol . kg-1 . min-1 administered intracarotidly and intravenously for 6 min were performed. Intracarotid isotonic infusions and intravenous hypertonic infusions did not significantly alter pAVP. Hypertonic intracarotid saline increased jugular vein pOsm and pNa+ in a dose-related fashion, whereas saphenous vein pOsm and pNa+ were not significantly changed after 6 min of infusion. Plasma vasopressin, compared with the isotonic intracarotid infusion (1.5 +/- 0.3 pg/ml), was increased (P less than 0.05) after hypertonic saline to 3.2 +/- 0.6 and 4.8 +/- 0.2 pg/ml for the 90 and 180 mumol . kg-1 . min-1 infusions, respectively. The cerebral osmolality indicated by jugular vein pOsm was therefore increased in the absence of changes in systemic pOsm during intracarotid hypertonic infusions. The increase in pAVP in response to these changes in pOsm supports the presence of central osmoreceptors regulating vasopressin release in the area of distribution of the common carotid arteries.     

Reversal of acute exacerbations of chronic obstructive lung disease by inspiratory assistance with a face mask

BACKGROUND. Patients with acute exacerbations of chronic obstructive pulmonary disease may require endotracheal intubation with mechanical ventilation. We designed, and here report on the efficacy of, a noninvasive ventilatory-assistance apparatus to provide inspiratory-pressure support by means of a face mask. METHODS. We assessed the short-term (45-minute) physiologic effects of the apparatus in 11 patients with acute exacerbations of chronic obstructive pulmonary disease and evaluated its therapeutic efficacy in 13 such patients (including 3 of the 11 in the physiologic study) who were treated for several days and compared with 13 matched historical-control patients. RESULTS. In the physiologic study, after 45 minutes of inspiratory positive airway pressure by face mask, the mean (+/- SD) arterial pH rose from 7.31 +/- 0.08 to 7.38 +/- 0.07 (P less than 0.01), the partial pressure of carbon dioxide fell from 68 +/- 17 mm Hg to 55 +/- 15 mm Hg (P less than 0.01), and the partial pressure of oxygen rose from 52 +/- 12 mm Hg to 69 +/- 16 mm Hg (P less than 0.05). These changes were accompanied by marked reductions in respiratory rate (from 31 +/- 7 to 21 +/- 9 breaths per minute, P less than 0.01). Only 1 of the 13 patients treated with inspiratory positive airway pressure needed tracheal intubation and mechanical ventilation, as compared with 11 of the 13 historical controls (P less than 0.001). Two patients in each group died. As compared with the controls, the treated patients had a more transient need for ventilatory assistance (3 +/- 1 vs. 12 +/- 11 days, P less than 0.01) and a shorter stay in the intensive care unit (7 +/- 3 vs. 19 +/- 13 days, P less than 0.01). CONCLUSIONS. Inspiratory positive airway pressure delivered by a face mask can obviate the need for conventional mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.     

Serum 1,25-dihydroxyvitamin D levels in normal subjects and in patients with hereditary rickets or bone disease.

The serum concentration of 1,25-dihydroxylvitamin D (1,25-[OH]2D) in normal children and in children with inherited diseases of bone was compared by use of a competitive binding assay. Observed values were: in 12 normal children and adolescents, 37.1 +/- 1.9 pg per milliliter (mean +/- S.D.); in 14 patients with X-linked hypophosphatemic rickets treated with vitamin D2 and phosphate supplements, 15.6 +/- 7.8 (P less than 0.01 versus control); in six patients with autosomal recessive vitamin D dependency treated with vitamin D2, 9.5 +/- 2.9 (P less than 0.01 versus control); and in four untreated patients with autosomal dominant hypophosphatemic (non-rachitic) bone disease, 30.2 +/- 6.3 (not significantly different from the controls). The difference in bone disease between X-linked hypophosphatemia (severe) and hypophosphatemic bone disease (mild) at comparable low serum levels of phosphate implies that 1,25-(OH)2D and phosphate may have independent roles in the pathogenesis of defective bone mineralization.     

Domiciliary metaproterenol nebulization: a bacteriologic survey

We wanted to determine whether domiciliary jet nebulization (DJN) leads to contamination of the equipment with fungi or aerobic bacteria and, eventually, to respiratory colonization or pneumonia in daily users of the equipment. We surveyed from this standpoint 23 veterans 65 +/- 10.1 years of age, present or former smokers, treated with steroids more than 7 months in the year preceding the survey, and with FEV1/FVC of 42 +/- 11%; they all were daily users of the equipment, diluting the metaproterenol solution with nonbacteriostatic saline dispensed in multiple-dose bottles of 500 to 1000 ml (protocol 1 [P1]). After this protocol was completed, the large saline bottles were replaced by 20 cc vials; 11/23 completed 1 year of this treatment (protocol 2 [P2]). Equipment contamination was checked in all initial 23 patients after one-time nebulization in the laboratory with fresh material (protocol 3 [P3]). We found that DJN leads to equipment contamination in 20/23 subjects of P1 and 3/11 subjects of p2; saline bottles and the nebulizer were the most frequently contaminated items (32/41 equipment items in P1 and 10/55 in P2). The contamination was predominantly bacterial with oropharyngeal saprophytes (19 in p1, O in P2) or gram-negative bacilli (47 in P1, 8 in P2). Bacterial growth was heavier in P1 than in P2. During P3, three equipment items became contaminated in 3/23 subjects; the flora was oropharyngeal. No patient developed respiratory colonization or developed pneumonia during 9000 patient days of DJN.(ABSTRACT TRUNCATED AT 250 WORDS)     

苦参素对HBsAg转基因小鼠血清Th1和Th2细胞因子水平的影响

目的　探讨苦参素对HBsAg转基因小鼠外周血Th1 Th2细胞因子水平的影响。方法　HBsAg转基因小鼠分成苦参素组和对照组 ,分别每天腹腔注射苦参素注射液 2 0 0mg kg 0 2ml和生理盐水 0 2ml,共 30d。处理前后 ,检测外周血清细胞因子水平。结果　对照组处理前后γ 干扰素(IFN γ)与白细胞介素 4 (IL 4 )水平差异无显著意义 ;苦参素组处理前后IFN γ分别为 (3 10 8± 3 172 )pg ml和 (11 0 5 9± 6 971)pg ml,IL 4分别为 (2 9 0 4 5± 13 2 35 )pg ml和 (13 0 2 4± 9 0 0 2 )pg ml(均P <0 0 0 1)。处理后对照组与苦参素组IL 2分别为 (1 0 70± 0 4 4 7)pg ml和 (5 5 37± 2 887)pg ml(P <0 0 0 0 1) ;IL 10分别为 (97 2 2 6± 73 30 6 )pg ml和 (33 6 0 7± 2 3 15 4 )pg ml(P <0 0 1)。结论　在苦参素作用后 ,HBsAg转基因小鼠体内的Th1型细胞因子明显升高 ,Th2型细胞因子明显降低。这将有助于研究苦参素临床治疗乙型肝炎的机制。     

Racial differences in aldosterone excretion and plasma aldosterone concentrations in children

Blacks are more likely to have hypertension, have lower levels of plasma renin activity, and typically consume less potassium than whites. Whether blacks and whites secrete different amounts of aldosterone is less clear. We estimated aldosterone secretion indirectly in 715 children, 249 of whom were black, by measuring their nocturnal rates of urinary excretion of aldosterone. Dietary sodium and potassium intakes were estimated from their excretion rates. The mean (+/- SE) aldosterone-excretion rate was lower in the black children than in the white children (0.045 +/- 0.003 vs. 0.078 +/- 0.004 nmol per micromole of creatinine per kilogram of body weight; P less than 0.001). The potassium-excretion rate was also lower in the black children than in the white children (0.13 +/- 0.01 vs. 0.18 +/- 0.01 mmol per micromole of creatinine per kilogram; P less than 0.001). Aldosterone excretion was highly correlated with potassium excretion (P less than 0.001), but the lower aldosterone-excretion rate in blacks was explained only in part by their lower dietary intake of potassium. Systolic blood pressure was higher in black children (P less than 0.001), as was diastolic pressure (P = 0.037). In a second study of 99 children, the plasma aldosterone level was found to be significantly lower in black children than in white children (230 +/- 30 vs. 400 +/- 30 pmol per liter; P less than 0.001). Plasma renin activity and plasma cortisol levels were the same in both groups. In summary, we found that black children secrete about 40 percent less aldosterone than white children. The role of the lower aldosterone-secretion rate in the genesis of the higher blood pressures observed in black children is not known.     

Effects of theophylline on erythropoietin production in normal subjects and in patients with erythrocytosis after renal transplantation

BACKGROUND. Erythrocytosis occurs in 10 to 15 percent of renal-transplant recipients, and there is in vitro evidence that the production of erythropoietin is modulated by adenosine. METHODS. We prospectively evaluated the effects of theophylline, a nonselective adenosine antagonist, in eight patients with erythrocytosis after renal transplantation and in five normal controls. RESULTS. After an eight-week course of theophylline treatment, the mean (+/- SEM) serum erythropoietin levels were significantly reduced in both the renal-transplant recipients (from 60 +/- 14 units per liter at base line to 9 +/- 7 units after treatment; P less than 0.05) and the normal subjects (from 6.9 +/- 0.8 units per liter at base line to 4.7 +/- 0.5 units per liter after treatment; P less than 0.05). Similarly, the hematocrits were reduced in both the transplant recipients (from 0.58 +/- 0.04 at base line to 0.46 +/- 0.03 after treatment; P less than 0.05) and the normal subjects (from 0.43 +/- 0.01 at base line to 0.39 +/- 0.01; P less than 0.05). In the renal-transplant recipients, red-cell mass was also reduced after eight weeks of theophylline (from 3197 +/- 82 ml at base line to 2273 +/- 69 ml after treatment; P less than 0.05). The previous requirement of weekly phlebotomy was eliminated in all recipients. Plasma and urinary cyclic AMP levels were not increased. These effects were reproducible when the subjects were rechallenged with theophylline after a recovery period. CONCLUSIONS. Theophylline attenuates the production of erythropoietin in both normal subjects and patients with erythrocytosis after renal transplantation and may be useful in the treatment of the latter condition.     

Growth of the pig: changes in red cell and plasma volumes.

In the pig, plasma volume increased from 58.0 +/- 2.53 ml/kg on day 1 to 66.7 +/- 3.35 (P less than 0.05) on day 2, and decreased between days 7 and 9 to 56.4 +/- 1.16 (P less than 0.02). The next significant change in volume occurred at weaning: from 53.1 +/- 1.24 ml/kg at week 4 to 44.16 +/- 2.2 at week 5. It then increased to 56.1 +/- 1.41 ml/kg by week 7 and decreased to 48.5 +/- 1.44 by week 9; then between weeks 10 and 11 it increased to 59.33 +/- 3.01 (P less than 0.005). Red cell volume on day 1 was 32.3 +/- 1.25 ml/kg and decreased to 20.2 +/- 1.37 (P less than 0.01) on day 2. The only other change of significance in red cell volume over the 12-week growth period was a small increasan 0.05) at week 6. The mean for BVRcells was 0.88 +/- 0.01 for the growth period. The pattern of changes in plasma and red cell volumes differed from those for the beagle.     

Plasma high-density lipoprotein concentrations in chronic-hemodialysis and renal-transplant patients.

Since epidemiologic studies show that the risk of clinically evident atherosclerosis correlates negatively with concentrations of high-density lipoprotein, we sought to determine whether patients on chronic hemodialysis or recipients of renal transplants had alterations in this lipoprotein similar to those described in other disorders associated with accelerated forms of atherosclerosis. High-density-lipoprotein cholesterol concentrations in both groups of renal patients were significantly lower than control values (P less than 0.01), and their ratios of low-density-lipoprotein to high-density-lipoprotein cholesterol were significantly higher (P less than 0.01) than those observed in both randomly selected controls and in controls matched for plasma lipid levels (control, 2.4 +/- 1.2, dialysis, 3.7 +/- 2.1, and transplant, 5.4 +/- 2.3 mg per 100 ml [mean +/- S.D.]) if, as experimental evidence suggests, high-density lipoprotein retards the development of atherosclerosis, and low-density lipoprotein has opposite effects, the higher ratio of low-density-lipoprotein to high-density-lipoprotein cholesterol found in chronic-dialysis and renal-transplant patients may be related to their premature morbidity and mortality from cardiovascular causes.