A randomized trial of automated intermittent ropivacaine administration vs. continuous infusion in an interscalene catheter

BACKGROUND

Ultrasound-guided interscalene nerve block with ropivacaine as local anesthetic agent given as boluses or continuous infusion is the preferred pain management after major shoulder surgery. The use of automated intermittent boluses has been shown to be superior to continuous infusion in sciatic and epidural nerve block.

HYPOTHESIS

Automated intermittent boluses reduce pain after major shoulder surgery.

METHODS

Seventy patients aged 18-75 years, scheduled for major shoulder surgery under general anesthesia with interscalene nerve block were included in this randomized controlled trial. Patients were allocated to either automated intermittent boluses with 16 mg ropivacaine every 2 h combined with patient-controlled administration or to a conventional regimen of continuous infusion of 8 mg/h (4 ml/h) of ropivacaine combined with patient controlled administration (2 ml, lockout time 30 min). Pain (Visual Analog Scale, VAS) was assessed every 8 h postoperatively.

RESULTS

Fifty-seven patients completed the study, 29 in the continuous infusion group and 28 in the automated intermittent bolus group. Shoulder arthroplasty was performed in 49 (86%) of the cases. There were no significant differences in VAS score from 8 to 48 h post-operatively. No significant difference in opioid usage was observed. The automated intermittent bolus group reported significantly less force on coughing and more hoarseness. A significantly lower volume of ropivacaine was used in the automated intermittent bolus group.

CONCLUSION

Automated intermittent boluses did not reduce pain or rescue opioid consumption compared with continuous infusion of ropivacaine. The automated intermittent bolus group had significantly less force on coughing and more hoarseness.

Conn's syndrome. A follow-up of thirteen surgically treated cases

Thirteen patients were followed for 4-46 months after removal of an aldosterone producing adenoma. Normotension was achieved in all cases but two in whom moderate diastolic hypertension was easily managed on diuretic therapy. All were cured of hypokalemia and symptoms related to low plasm potassium. Persistaent selective hypoaldosteronism was seen in one patient. A gratifying regression of symptoms and signs related to arterial hypertension was seen. Medical treatment with aldosterone antagonists may "cure" the patient to the same extent as surgery. The present results encourage the use of surgical treatment in these young patients since a life-long drug therapy--with its attendant problems--is the only alternative.

Simple screening procedure for the diagnosis of primary aldosteronism

A simple screening protocol for the diagnosis of primary aldosteronism was applied to 149 hypertensive patients. The diagnostic criterion for possible primary aldosteronism was the combination of supine plasma renin concentration less than 15 mIU/l (normal range 6-54) and plasma aldosterone concentration greater than 11 ng/100 ml (normal range 3-18). None of 63 persistently normokalaemic hypertensive patients fulfilled this criterion. Seventeen (20%) of 86 hypokalaemic patients showed hormonal values consistent with primary aldosteronism. The presence of an adrenal adenoma was verified in eight of these patients. Thus screening for primary aldosteronism can be restricted to hypokalaemic patients. The prevalence of primary aldosteronism in a hypertensive population was calculated to be less than 1%.

Localization of aldosterone-producing tumours in primary aldosteronism by adrenal and renal vein catheterization

Regional venous plasma aldosterone concentrations were determined and assessed against concurrent arterial levels in 16 patients with primary aldosteronism. The results obtained by sampling from the left adrenal vein or the left renal vein allowed correct side prediction of the presupposed adenoma in each patient. The problems caused by intermittent secretion of aldosterone by the tumour and the importance of correct positioning of the catheter are emphasized. Repeated sampling and continuing reference to systemic, arterial aldosterone levels proved valuable.

A follow-up study of hypertensive patients after operative treatment of unilateral renovascular or renal disease

A study of 44 hypertensive patients with unilateral renovascular or renal parenchymal disease is presented. All patients underwent corrective surgery. Out of the 44 operated patients, five did not participate in the follow-up examination. The remaining 39 patients constitute the study population. The effects of surgery on the hypertensive state could be evaluated in 35 patients, whereas four died less than two months after the operation. Follow-up studies were carried out at 8-60 months after the operation. The average period of observation was 32 months; 24 patients were observed for more than two years. As a group, the patients had severe hypertension with extensive target organ damage and widespread atherosclerosis. A fairly rigorous selection process was applied, and an unsatisfactory response to medical management was considered a point of major importance. In the majority of cases, renovascular lesions were atherosclerotic, with only two cases of fibromuscular dysplasia. Unilateral nephrectomy was performed in 32 patients, whereas seven underwent reconstructive vascular surgery. Out of 35 patients, 22 (63%) were cured, 8 (23%) improved and 5 (14%) unaltered. A gratifying regression of hypertensive lesions in target organs was observed in patients who were cured or improved by surgery. The frequency and severity of postoperative complications were related to the presence of extrarenal vascular disease.

Impaired glucose tolerance in the R6/1 transgenic mouse model of Huntington's disease

Previous reports have highlighted a possible link between Huntington's disease (HD) and diabetes mellitus (DM), but the association has not been characterised in detail. A transgenic mouse model for HD, the R6/2 mouse, also develops diabetes. In the present study, we examined the R6/1 mouse, which carries a shorter CAG repeat than the R6/2 mouse, and found that, although not diabetic, the mice showed several signs of impaired glucose tolerance. First, following i.p. glucose injection, the blood glucose concentration was approximately 30% higher in young R6/1 mice (10 weeks) compared to wild-type mice (P = 0.004). In older mice (38 weeks), glucose tolerance was further impaired in both R6/1 and wild-type animals. Second, during glucose challenge, the R6/1 mice reached higher plasma insulin levels than wild-type mice, but the peripheral insulin sensitivity was normal as measured by injection of human or mouse insulin or when evaluated by the quantitative insulin sensitivity check index (QUICKI). Third, the beta cell volume was 17% and 39% smaller at 10 and 38 weeks of age, respectively, compared to age-matched wild-type littermates and the reduction was not caused by apoptosis at either age. Finally, we demonstrated the presence of the HD gene product, huntingtin (htt), in both alpha- and beta-cells in R6/1 islets of Langerhans. Since pancreatic beta cells and neurons share several common traits, clarification of the mechanism associating neurodegenerative diseases with diabetes might improve our understanding of the pathogenic events leading to both groups of diseases.

Broadband single-polarization photonic crystal fiber

We demonstrate a single-mode photonic crystal fiber that supports only one polarization state in a 220-nm-broad spectral region centered at 727 nm. The fiber has a mode-field diameter of 15.5 microm and background losses of < 15 dB/km in the single-polarization region. To our knowledge, these are the broadest bandwidth and the largest mode size yet reported for a single-polarization fiber.

Improved large-mode-area endlessly single-mode photonic crystal fibers

We numerically study the possibilities for improved large-mode-area endlessly single-mode photonic crystal fibers for use in high-power delivery applications. By carefully choosing the optimal hole diameter, we find that a triangular core formed by three missing neighboring air holes considerably improves the mode area and loss properties compared with the case with a core formed by one missing air hole. In a realized fiber we demonstrate an enhancement of the mode area by approximately 30% without a corresponding increase in the attenuation.

Regulation and immunohistochemical localization of betagamma-stimulated adenylyl cyclases in mouse hippocampus

Specific forms of synaptic plasticity such as long-term potentiation (LTP) are modulated by or require increases in cAMP. The various adenylyl cyclase isoforms possess unique regulatory properties, and thus cAMP increases in a given cell type or tissue in response to converging signals are subject to the properties of the adenylyl cyclase isoforms expressed. In most tissues, adenylyl cyclase activity is stimulated by neurotransmitters or hormones via stimulatory G-protein (Gs)-coupled receptors and is inhibited via inhibitory G-protein (Gi)-linked receptors. However, in the hippocampus, stimulation of Gi-coupled receptors potentiates Gs-stimulated cAMP levels. This effect may be associated with the regulatory properties of adenylyl cyclase types 2 and 4 (AC2 and AC4), isoforms that are potentiated by the betagamma subunit of Gi in vitro. Although AC2 has been shown to be stimulated by betagamma in whole cells, reports describing the sensitivity of AC4 to betagamma in vivo have yet to emerge. Our results demonstrate that Gs-mediated stimulation of AC4 is potentiated by betagamma released from activated Gi-coupled receptors in intact human embryonic kidney (HEK) 293 cells. Furthermore, we show that the AC2 and AC4 proteins are expressed in the mouse hippocampal formation and that they colocalize with MAP2, a dendritic and/or postsynaptic marker. The presence of AC2 and AC4 in the hippocampus and the ability of each of these enzymes to detect coincident activation of Gs- and Gi-coupled receptors suggest that they may play a crucial role in certain forms of synaptic plasticity by coordinating such overlapping synaptic inputs.

[Unintended events in anesthesia due to reuse of disposable equipment]

Two cases concerning reuse of plastic-coated introducers (intended for single-use only) for intubation of children are described. If breaks in the coating occur, the airway can be compromised and removal of the broken piece of the plastic-coating can the treacherous. In this paper, the probable causes of the incidents are discussed and suggestions for avoiding breakage are outlined.

Stimulation of type 1 and type 8 Ca2+/calmodulin-sensitive adenylyl cyclases by the Gs-coupled 5-hydroxytryptamine subtype 5-HT7A receptor

The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) plays an important regulatory role in developing and adult nervous systems. With the exception of the 5-HT3 receptor, all of the cloned serotonin receptors belong to the G protein-coupled receptor superfamily. Subtypes 5-HT6 and 5-HT7 couple to stimulation of adenylyl cyclases through Gs and display high affinities for antipsychotic and antidepressant drugs. In the brain, mRNA for 5-HT6 is found at high levels in the hippocampus, striatum, and nucleus accumbens. 5-HT7 mRNA is most abundant in the hippocampus, neocortex, and hypothalamus. To better understand how serotonin might control cAMP levels in the brain, we coexpressed 5-HT6 or 5-HT7A receptors with specific isoforms of adenylyl cyclase in HEK 293 cells. The 5-HT6 receptor functioned as a typical Gs-coupled receptor in that it stimulated AC5, a Gs-sensitive adenylyl cyclase, but not AC1 or AC8, calmodulin (CaM)-stimulated adenylyl cyclases that are not activated by Gs-coupled receptors in vivo. Surprisingly, serotonin activation of 5-HT7A stimulated AC1 and AC8 by increasing intracellular Ca2+. 5-HT also increased intracellular Ca2+ in primary neuron cultures. These data define a novel mechanism for the regulation of intracellular cAMP by serotonin.

Differential regulation of type I and type VIII Ca2+-stimulated adenylyl cyclases by Gi-coupled receptors in vivo

Coupling of intracellular Ca2+ to cAMP increases may be important for some forms of synaptic plasticity. The type I adenylyl cyclase (I-AC) is a neural-specific, Ca2+-stimulated enzyme that couples intracellular Ca2+ to cAMP increases. Since optimal cAMP levels may be crucial for some types of synaptic plasticity, mechanisms for inhibition of Ca2+-stimulated adenylyl cyclases may also be important for neuroplasticity. Here we report that Ca2+ stimulation of I-AC is inhibited by activation of Gi-coupled somatostatin and dopamine D2L receptors. This inhibition is due primarily to Gialpha and not betagamma subunits since coexpression of betagamma-binding proteins with I-AC did not affect somatostatin inhibition. However, betagamma released from Gs did inhibit I-AC, indicating that the enzyme can be inhibited by betagamma in vivo. Interestingly, type VIII adenylyl cyclase (VIII-AC), another Ca2+-stimulated adenylyl cyclase, was not inhibited by Gi-coupled receptors. These data indicate that I-AC and VIII-AC are differentially regulated by Gi-coupled receptors and provide distinct mechanisms for interactions between the Ca2+ and cAMP signal transduction systems. We propose that I-AC may be particularly important for synaptic plasticity that depends upon rapid and transient cAMP increases, whereas VIII-AC may contribute to transcriptional-dependent synaptic plasticity that is dependent upon prolonged, Ca2+-stimulated cAMP increases.

[Screening for prehypoxemia with oximetry--a study of two methods]

The aim of the present study was to evaluate the validity of pulse oximetry screening for prehypoxaemia, to assess the agreement between pulse- and haem-oximetry and to elucidate any influence of peripheral temperature on pulse oximeter measurements. A consecutive prospective study was undertaken in 91 cardiac surgery patients still in treatment with controlled mechanical ventilation in the early postoperative period. We examined arterial oxygen tension (paO2), arterial oxygen saturation (SaO2) and pulse oximeter saturation (SpO2) from 657 arterial blood samples. The sensitivity of the pulse oximeter was 0.83, the specificity 0.73, and the diagnostic specificity was 0.10, at the chosen level of screening. The pulse oximeter showed a tendency to underestimate the oxygen saturation by 0.85%. The agreement between pulse- and haem-oxymetry was found to be good. The authors conclude that the pulse oximeter is acceptable for respiratory screening in postoperative cardiac surgery. The low specificity and the low diagnostic specificity results in frequent false alarms. Low peripheral temperature (down to 25%) do not influence the validity of either methods.

Developmentally expressed Ca(2+)-sensitive adenylyl cyclase activity is disrupted in the brains of type I adenylyl cyclase mutant mice

The type I Ca(2+)-sensitive adenylyl cyclase has been implicated in several forms of synaptic plasticity in vertebrates. Mutant mice in which this enzyme was inactivated by targeted mutagenesis show deficient spatial memory and altered long term potentiation (Wu, Z. L., Thomas, S. A., Villacres, E. C., Xia, Z., Simmons, M. L., Chavkin, C., Palmiter, R. D., and Storm, D. R. (1995) Proc. Natl Acad Sci. U. S. A. 92, 220-224). Long term potentiation in the CA1 region of the rat hippocampus develops during the first 2 weeks after birth and reaches maximal expression at postnatal day 15 with a gradual decline at later stages of development. Here we report that Ca(2+)-stimulated adenylyl cyclase activity in rat hippocampus, cerebellum, and cortex increases significantly between postnatal days 1-16. This increase appears to be due to enhanced expression of type I adenylyl cyclase rather than type VIII adenylyl cyclase, the other adenylyl cyclase that is directly stimulated by Ca2+ and calmodulin. Type I adenylyl cyclase mRNA in the hippocampus increased 7-fold during this developmental period. The developmental expression of Ca(2+)-stimulated adenylyl cyclase activity in mouse brain was attenuated in mutant mice lacking type I adenylyl cyclase. Changes in expression of the type I adenylyl cyclase during the period of long term potentiation development are consistent with the hypothesis that this enzyme is important for neuroplasticity and spatial memory in vertebrates.

Phosphorylation of the human leukemia inhibitory factor (LIF) receptor by mitogen-activated protein kinase and the regulation of LIF receptor function by heterologous receptor activation

We used a bacterially expressed fusion protein containing the entire cytoplasmic domain of the human leukemia inhibitory factor (LIF) receptor to study its phosphorylation in response to LIF stimulation. The dose- and time-dependent relationships for phosphorylation of this construct in extracts of LIF-stimulated 3T3-L1 cells were superimposable with those for the stimulation of mitogen-activated protein kinase (MAPK). Indeed, phosphorylation of the cytoplasmic domain of the low-affinity LIF receptor alpha-subunit (LIFR) in Mono Q-fractionated, LIF-stimulated 3T3-L1 extracts occurred only in those fractions containing activated MAPK; Ser-1044 served as the major phosphorylation site in the human LIFR for MAPK both in agonist-stimulated 3T3-L1 lysates and by recombinant extracellular signal-regulated kinase 2 in vitro. Expression in rat H-35 hepatoma cells of LIFR or chimeric granulocyte-colony-stimulating factor receptor (G-CSFR)-LIFR mutants lacking Ser-1044 failed to affect cytokine-stimulated expression of a reporter gene under the control of the beta-fibrinogen gene promoter but eliminated the insulin-induced attenuation of cytokine-stimulated gene expression. Thus, our results identify the human LIFR as a substrate for MAPK and suggest a mechanism of heterologous receptor regulation of LIFR signaling occurring at Ser-1044.

Oxidation of critical cysteine residues of type I adenylyl cyclase by o-iodosobenzoate or nitric oxide reversibly inhibits stimulation by calcium and calmodulin

The calmodulin binding domain of the type I adenylyl cyclase has recently been identified as an amino acid sequence (residues 495-522) that contains 2 cysteine residues. Therefore, we examined the effect of several sulfhydryl reagents on the calmodulin sensitivity of the enzyme. Treatment of membranes containing the type I adenylyl cyclase with N-ethylmaleimide rapidly inhibited basal, calcium/calmodulin-stimulated, and forskolin-stimulated adenylyl cyclase activity. When the enzyme was treated with limiting amounts of o-iodosobenzoate, which oxidizes vicinal sulfhydryls to disulfides, stimulation by Ca2+ and calmodulin was eliminated at concentrations which did not affect basal adenylyl cyclase activity. Calmodulin stimulation of the enzyme was restored by treatment with dithiothreitol or glutathione which reduce disulfides to free thiols. NO and sodium nitroprusside also reversible inhibited calmodulin stimulation of the enzyme. We propose that the loss in calmodulin sensitivity caused by these reagents may be due to the oxidation one or more sets of vicinal thiols present in the enzyme.

Fate of circulating amino-terminal propeptide of type III procollagen in conscious pigs

The amino-terminal propeptide of type III procollagen (PIIINP, M(r) 42,000) is a promising marker for the formation of type III collagen of granulation tissue in experimental and clinical studies. The disposal kinetics of circulating PIIINP is, however, almost unknown. In conscious pigs with a thoracic duct-venous shunt, 125I-labeled PIIINP was injected intravenously. The initial distribution volume was 2.2 liters, which was 1.7 times the plasma volume (P < 0.01). The disappearance curve was three-phased, with an initial steep decline (t1/2 58 min), followed by two slower phases (t1/2 239 min and 289 h). Consecutive gel filtrations showed that the initial slope of the plasma disappearance curve corresponded to the plasma clearance of the intact PIIINP. The initial plasma clearance was 26.5 ml plasma/min, whereas the urinary clearance was 8.7 ml plasma/min (P < 0.01). The other components of the plasma disappearance curve originated from the formation and disappearance of a high and a low molecular weight (MW) fraction as part of the degradation of PIIINP. The high MW fraction (approximately M(r) 90,000) was similar to a previously described, but not further characterized, PIIINP immunoreactive component. The existence of the low MW fraction (approximately M(r) 20,000) has not been reported before. The lymphatic recirculation of intact PIIINP was rapid, and the lymph-serum ratio was almost constant within 1 h of injection. We conclude that the t1/2 of circulating PIIINP is 58 min, that PIIINP escapes the circulation very quickly, and that the degradation of PIIINP includes at least two intermediary steps.

Purification of porcine aminoterminal propeptide of type III procollagen from lymph and use for lymphatic clearance studies in pigs

To investigate the lymphatic transport of the aminoterminal propeptide of type III procollagen (PIIINP) we established a thoracic duct-venous shunt in 6 pigs. Porcine PIIINP was purified, characterised, and compared with human PIIINP to ensure the suitability of the radioimmunoassay of human PIIINP for measurements in pigs. SDS-PAGE and radioimmunoinhibition assays show human and porcine PIIINP to be similar, thus indicating that the assay of human PIIINP is also reliable for determinations on pig serum and lymph. Intact PIIINP, as identified by gel filtration, accounted for 60% and 40% of the total PIIINP immunoreactivity in lymph and serum, respectively. The higher amount of total immunoreactivity and proportion of intact PIIINP in lymph compared with serum support the hypothesis that intact PIIINP is transported from peripheral tissue into the circulation by lymph. Two days after the shunt was established, the lymph was collected quantitatively hour-by-hour for 24 h. The flow was higher during the light periods than in the dark (p less than 0.01). The PIIINP concentration varied inversely with the flow, being higher in the dark hours (p less than 0.03). However, the total collected amount of PIIINP in lymph did not differ during the light and dark periods. Serum PIIINP remained unchanged over the 24 h. The lymphatic clearance of total PIIINP immunoreactive components was 6.2 ml serum/min and the lymphatic clearance of intact PIIINP was 9.1 ml serum/min, equal to 7 and 10 times the plasma volume/24 h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Left-ventricular performance, volumes, and catecholamine responses during anaesthesia induction--monitoring by combined radionuclide cardiography and right heart catheterization

Sequential radionuclide imaging and continuous recording of arterial and right heart pressures were carried out during anaesthesia with midazolam 0.2 mg kg-1, pancuronium 0.15 mg kg-1 and fentanyl 10 micrograms kg-1 in eight patients with normal cardiopulmonary status scheduled for craniotomy. The aim was to examine how a stress-free anaesthetic induction tailored to protect against the hypertension and tachycardia provoked by laryngoscopy and intubation influenced left-ventricular performance, left-ventricular loading conditions and plasma catecholamine concentrations. During the 20-min study period no significant changes were observed in heart rate, left-ventricular ejection fraction, ratio of peak systolic pressure to left-ventricular end-systolic volume, pulmonary capillary wedge pressure, left-ventricular end-systolic volume, cardiac output, dopamine and noradrenaline concentrations. Except for a minor increase in mean arterial pressure after laryngoscopy and intubation, mean arterial pressure decreased 24%, left-ventricular end-diastolic volume decreased 15%, and left-ventricular stroke volume decreased 21%. Central venous pressure increased by 75% but there was no parallel increase in pulmonary wedge pressure, which in turn did not reflect the alterations in ventricular end-diastolic volume. Plasma adrenaline concentrations decreased significantly (66%). The chosen induction regimen preserved global left-ventricular pump function during laryngoscopy and intubation without any activation of the sympathetic nervous system. Central venous and pulmonary wedge pressures were unreliable in the assessment of ventricular preload during induction of general anaesthesia.

Solid-phase double-antibody radio-immunoassay for atrial natriuretic factor

A solid-phase radio-immunoassay for the determination of atrial natriuretic factor (ANF) in human plasma is described. Iodination of alpha hANF was carried out with the iodogen method. Purification of radio-iodinated alpha hANF was performed by chromatography on disposable columns of DEAE-Sephadex A-25. Studies of immunoreactivity and the elution pattern on HPLC showed perfect stability of the labelled compounds. The tracer was usable for 28 weeks after preparation, and the batch-to-batch variation in the quality of the tracer was satisfactory. Immunoreactive ANF was extracted from human plasma with Sep-Pak C18 cartridges. Recovery of alpha hANF added to whole blood was 85 +/- 12% (mean +/- SD, n = 12). The sensitivity of the radio-immunoassay was 1.6 pg/tube, equivalent to 1 pg/ml plasma when assaying the extract from 4 ml plasma. Mean plasma ANF values in normal subjects in the supine position was 23 +/- 12 pg/ml (mean +/- SD, n = 21).

Pseudohypoaldosteronism in eight families: different forms of inheritance are evidence for various genetic defects

Pseudohypoaldosteronism is a rare hereditary disorder presenting in early infancy with renal salt loss leading to hyponatremia and hyperkalemia despite high levels of plasma aldosterone. The patients are insensitive to mineralocorticoids; however, sodium supplementation is able to correct electrolyte abnormalities. Absent or greatly diminished type I aldosterone receptors in peripheral mononuclear leucocytes have been recently demonstrated and explain the lack of response to mineralocorticoids. We have studied the mode of inheritance in eight families with a total of nine patients. There was evidence for an autosomal recessive form of inheritance in four families, while the other four families appeared to have an autosomal dominant mode of transmission. In three families the autosomal recessive form was characterized by normal receptor as well as hormone data in both parents, while in one family receptor levels in both parents were greatly reduced, but hormone levels were normal. In the four families with an autosomal dominant mode of transmission there was always one parent with reduced receptor binding in peripheral mononuclear leucocytes and elevated serum hormone levels. These parents were entirely asymptomatic. In an extended family we were able to study an aunt and her newborn daughter, who were both also biochemically affected but clinically asymptomatic. It, therefore, appears that this dual pattern of genetic transmission may indicate differing genetic defects which cause the same clinical picture of pseudohypoaldosteronism.

A dose-effect study of the in vivo inhibitory effect of quinidine on sparteine oxidation in man

1. Twelve healthy extensive metabolisers of sparteine were sparteine tested daily for 6 days (19.00 h to 07.00 h). A small but statistically significant rise in sparteine metabolic ratio (MR) was observed. 2. Following 100 mg quinidine sulphate given to four of the subjects at 16.00 h, sparteine tests were carried out 19.00 h to 07.00 h on the same day and then daily for 6 days. Quinidine caused an immediate twenty-fold increase in sparteine-MR which then gradually returned to normal over the following 4-6 days. Quinidine concentrations in plasma were measurable only up to 20 h after the quinidine test dose. 3. At weekly intervals, all 12 subjects received single doses of quinidine sulphate of 5, 10, 20, 40 and 80 mg at 16.00 h, each time followed by a sparteine test 19.00 h to 07.00 h on the same day. A clear dose-effect relationship was found with a significant rise in the sparteine-MR even after 5 mg quinidine. After 80 mg quinidine, 8 of 12 subjects became phenotypically poor metabolisers (MR greater than 20).

Captopril treatment in Bartter's syndrome

A 13-year-old girl presented with lassitude, polyuria and hypokalemia. Plasma renin concentration and urinary prostaglandin excretion were elevated, whereas plasma aldosterone concentration, urinary aldosterone excretion and blood pressure were normal. A diagnosis of Bartter's syndrome was made. The result of treatment with oral potassium was unsatisfactory. Treatment with acetylsalicylic acid had some effect, but an allergic reaction rendered withdrawal necessary. Treatment with the angiotensin converting enzyme inhibitor captopril and oral potassium led to clinical and biochemical improvement.

Autoimmune involvement in Cushing syndrome due to primary adrenocortical nodular dysplasia

Cushing syndrome due to primary adrenocortical nodular dysplasia was diagnosed in two patients, aged 3 years 9 months and 9.5 years. Subsequently, adrenalectomy was performed and followed by steroid replacement. In both cases, the adrenals were normal or only slightly enlarged and showed adrenocortical nodular dysplasia histologically. Small lymphocytic infiltrates consisting of T-cells and class II MHC positive macrophages were present in adrenal specimens of both the patients. Samples of protein A sepharose purified serum immunoglobulins from both children stimulated adrenocortical DNA synthesis and cortisol production in cultured guinea-pig adrenal segments in vitro in a dose dependent fashion. Adrenal stimulating immunoglobulins were also demonstrated in serum specimens of both patients' mothers. However, none of them had overt signs of adrenal disease. Our data support the view that autoimmune mechanisms may be involved in primary adrenocortical nodular dysplasia.

On the pathogenesis of arterial blood pressure elevation early in the course of diabetic nephropathy

We measured plasma- and extracellular fluid volume (125I-albumin, 51Cr-EDTA), plasma concentrations of renin, angiotensin I and II, aldosterone and atrial natriuretic peptide by radio-immunoassays in insulin-dependent diabetic (IDDM) patients with (n=28) and without (n=11) nephropathy and in 14 normal control subjects matched for sex and age. Glomerular filtration rate (GFR) (ml/min/1.73 m2, single intravenous bolus 51Cr-EDTA technique) was within normal range in all nephropathic patients; 107 (range 78-134). Mean arterial blood pressure (mmHg) was elevated 102 +/- 13 (+/- S.D.) compared to the diabetic and normal control group, 92 +/- 8 and 87 +/- 5, respectively (p less than 0.01). Plasma volume was identical in all three groups while extracellular volume (1/1.73 m2) was expanded in nephropathic patients, 14.5 +/- 1.5 vs 13.1 +/- 0.9 and 12.4 +/- 1.3 in the diabetic and non-diabetic control groups, respectively (p less than 0.05). A significant correlation between extracellular fluid volume and mean arterial blood pressure was found (n=53, r=0.49, p less than 0.001). Active renin was significantly increased in patients with diabetic nephropathy compared with the normal control subjects, while all the remaining hormones were about the same in the three groups. Our study suggests that fluid retention plays a dominant role in the initiation and maintenance of arterial blood pressure elevation early in the course of diabetic nephropathy.

Effects of insulin on kidney function and sodium excretion in healthy subjects

Insulin action on kidney function was evaluated in 8 healthy subjects, (mean age 27 years) using the euglycaemic clamp technique. Insulin was infused at rates of 0, 20 and 40 mU.min-1.m-2 over consecutive periods of 120 min resulting in plasma insulin concentrations of 8 +/- 2, 29 +/- 7 and 66 +/- 14 mU/l. The renal clearance of 51Cr-EDTA, lithium, sodium and potassium was determined during the last 90 min of each period. Sodium clearance declined with increasing plasma insulin concentrations (1.3 +/- 0.4, 1.0 +/- 0.3 and 0.5 +/- 0.2 ml.min-1.1.73 m-2, p less than 0.001), while glomerular filtration rate (108 +/- 21, 104 +/- 21 and 108 +/- 20 ml.min-1. 1.73 m-2) and lithium clearance (a marker of fluid flow rate from the proximal tubules) 29 +/- 5, 29 +/- 4 and 30 +/- 4 ml.min-1.1.73 m-2) remained unchanged. Calculated proximal tubular reabsorption of sodium and water was unchanged, while calculated distal fractional sodium reabsorption increased (95.5 +/- 1.5, 96.4 +/- 1.2 and 98.1 +/- 0.7%, p less than 0.001). Potassium clearance and plasma potassium concentration declined, whereas plasma aldosterone and plasma renin concentrations were unchanged. In conclusion, elevation of plasma insulin concentration within the physiological range has a marked antinatriuretic action. This effect is located distally to the proximal renal tubules.

Plasma concentrations of adrenaline, noradrenaline and dopamine during forearm dynamic exercise

In six healthy volunteers plasma concentrations of adrenaline, noradrenaline and dopamine were measured at rest and during dynamic forearm exercise at submaximal and maximal intensities. Arterial and venous concentrations of adrenaline and noradrenaline increased with forearm exercise at all workloads. Dopamine concentrations did not change. The increases in adrenaline and noradrenaline were almost linearly related to the increase in heart rate with no levelling off at maximal exercise intensities. It is concluded that dynamic exercise with the forearm muscle group causes a small but significant activation of the sympatho-adrenal system as reflected by increases in plasma concentrations of adrenaline and noradrenaline.

Removing a retained placenta by oxytocin--a controlled study

No increase in maternal plasma oxytocin concentration was detected after administration of 100 IU oxytocin into the umbilical veins of seven women immediately after delivery. The delivery of the placenta was accelerated after umbilical vein injection of 100 IU oxytocin in a placebo-controlled study of 40 women: 12 minutes (4 to 40) in the oxytocin group versus 40 minutes (29 to 40) in the placebo group (median and interquartile ranges), p less than 0.05.

Changed cyclic guanosine monophosphate atrial natriuretic factor relationship in hypertensive man

Plasma concentrations of atrial natriuretic factor (ANF) and cyclic guanosine monophosphate (cGMP) were measured in 10 patients with essential hypertension and 10 normotensive controls on the fifth day of a low (50 mmol/day), a medium (180 mmol/day) and a high (380 mmol/day) dietary sodium intake. Plasma ANF and cGMP concentrations were less on the low than on the high sodium intake. Values for ANF on the medium sodium intake were intermediate. In normotensive subjects cGMP concentrations did not differ significantly on the low and the medium sodium intake. As compared with the controls plasma concentrations of cGMP were significantly increased in hypertensive patients on all three levels of sodium intake, while ANF concentrations were identical in the two groups. Since cGMP is a second messenger to ANF the data suggest an increased cellular response to ANF in patients with essential hypertension.

Male pseudohermaphroditism due to 5 alpha-reductase deficiency in a Swedish family

Three sibs with an inherited form of male pseudohermaphroditism are described. They were all born with ambiguous external genitalia but no diagnosis of a possible enzyme defect was made during childhood. First seen at the ages of 16, 14 and 10 years respectively, they were investigated in order to establish the pathogenetic nature of the disorder. Serum concentrations of testosterone and dihydrotestosterone before and after stimulation with human chorionic gonadotropin suggested 5 alpha-reductase deficiency. Measurement of steroid metabolites in urine confirmed this diagnosis. It is essential to recognize this condition in order to decide the sex of rearing of the children.

Central role for sodium in the pathogenesis of blood pressure changes independent of angiotensin, aldosterone and catecholamines in type 1 (insulin-dependent) diabetes mellitus

We studied 73 Type 1 (insulin-dependent) diabetic patients, 18 to 50 years of age, with a diabetes duration of more than five years. Group 1: normal urinary albumin excretion below 30 mg per 24 h (n = 19); group 2: microalbuminuria, 30-300 mg per 24 h (n = 36); and group 3: diabetic nephropathy, above 300 mg per 24 h (n = 18). Fifteen nondiabetic persons matched for sex and age served as control subjects. The sodium intake evaluated on the basis of 24-h urine sodium excretion was similar in patients and control subjects. Blood pressure in groups 1 and 2 and control subjects was below 160/95 mmHg. The blood pressure was increased in group 3 as compared with the other groups (systolic/diastolic 161 +/- 22/101 +/- 9 mmHg vs 131 +/- 13/84 +/- 10, mean +/- SD, p less than 0.0001). Exchangeable sodium was increased in patients (p less than 0.01) and correlated to the mean blood pressure (n = 70, r = 0.41, p less than 0.01). Extracellular volume was increased in patients (p less than 0.05), whereas plasma volume was normal. Supine serum angiotensin II was suppressed in the patients (p less than 0.001). A negative correlation was found between mean blood pressure and supine serum aldosterone (n = 68, r = -0.24, p less than 0.05), and exchangeable sodium and aldosterone (n = 66, r = -0.36, p less than 0.002) in all patients. The catecholamine levels were also suppressed or normal in the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A highly sensitive and reproducible immunoradiometric assay for total human renin using monoclonal antibodies, iodogen labelling and polystyrene star tubes

A two-site immunoradiometric assay for total renin concentration in human plasma is described. A new type of polystyrene tubes with a special bottom geometry, so-called Star Tubes were used. The lower limit of detection was 2 microIU per ml and the working range from 2 to 2000 microIU per ml. The variation for duplicate determinations on standards and plasma samples was 2.7% and the day to day variation was 4.8%. No significant interferences or cross reactivities were identified. EDTA-plasma was analyzed after dilution with a phosphate buffer. Plasma samples from different patient categories were analyzed. The results were compared with those obtained by our substrate enrichment method after acid activation of the samples had taken place. A linear correlation (r = 0.990) between the results obtained with the two methods was found.

Lack of effect of nifedipine on counterregulatory mechanisms in essential hypertension

The influence of long-term nifedipine treatment on body fluid compartments, renal function, the renin-angiotensin system, and the adrenergic system was studied in 18 patients with essential hypertension. A placebo period of 4 weeks was followed by a 6-week dose-titration period. Thereafter, the dose was kept constant for an additional 6 weeks (mean dose, 51 mg/day). As compared with placebo values, diastolic blood pressure decreased approximately 12% during nifedipine treatment. Plasma volume, extracellular fluid volume, and the ratio of plasma to interstitial fluid volume did not change significantly, either in the group as a whole or in a subgroup in which pedal edema developed. Plasma concentrations of epinephrine and norepinephrine increased slightly after 2 weeks of treatment, but they returned to control values after 6 weeks of therapy. Plasma concentrations of renin, angiotensin II, and aldosterone did not change significantly. Glomerular filtration rate and renal clearances of sodium and potassium were unchanged as well. These results indicate that long-term nifedipine treatment does not lead to activation of counterregulatory mechanisms, such as fluid retention or the renin-angiotensin or adrenergic systems. This may well be of importance for the antihypertensive efficacy of nifedipine treatment.

Effects of combined therapy with amiloride and hydrochlorothiazide on plasma and total body potassium, blood pressure, and the renin-angiotensin-aldosterone system in hypertensive patients

After a run-in period of 8 weeks on a regimen of hydrochlorothiazide (HCT, median dosage 75 mg/day), patients with essential hypertension were randomly allocated to continued hydrochlorothiazide therapy (Group I) or additional treatment with amiloride (Group II, median dosage 15 mg/day, or 5 mg per 25 mg hydrochlorothiazide) for the following 12 weeks. Thereafter all the patients were changed to treatment with a fixed combination tablet containing 5 mg amiloride and 50 mg hydrochlorothiazide (Moduretic), keeping the thiazide dosage unchanged for an additional 12 weeks. In Group I patients there was no change in plasma potassium, total body potassium content or the renin-angiotensin-aldosterone system during the 12 weeks on HCT. When the treatment was changed to Moduretic, significant increases were found of 10% in plasma potassium and 3% in total body potassium content. No important stimulation of the renin-angiotensin-aldosterone system was found. In Group II patients addition of an average of 15 mg amiloride to the hydrochlorothiazide treatment led to significant increases in plasma potassium and total body potassium content of approximately 15% and 4%, respectively. There was also a significant increase in the plasma concentrations of renin, angiotensin II and aldosterone. Reducing the average dose of amiloride to 7.5 mg/day by use of Moduretic did not lead to decrease in plasma potassium or total body potassium content. Plasma concentrations of renin, angiotensin II, and aldosterone were decreased, but the individual changes varied markedly and no significant overall change was found.

The influence of nifedipine treatment on counter-regulatory mechanisms in essential hypertension

The influence of nifedipine treatment on plasma (PV) and extracellular fluid volume (ECV), the ratio of plasma volume to interstitial fluid volume (PV:IF), glomerular filtration rate (GFR), renal clearances of Na+ and K+, plasma concentrations of renin (PRC), angiotensin II (pANG II), aldosterone (pAldo), adrenaline (PA) and noradrenaline (PNA) were studied in 18 consecutive patients with essential hypertension. A 4-week placebo period was followed by a 6-week dose-titration period (period A). Thereafter the dose was kept constant for an additional 6 weeks (period B), the mean dose being 51 mg/day. As compared with placebo, diastolic blood pressure (DBP) decreased from 105 +/- 7 to 93 +/- 9 mmHg at the end of period B. Extracellular fluid volume, PV, and PV:IF were not significantly changed at the end of period A or B, neither in the group as a whole nor in a subgroup, who developed pedal oedema. After 2 weeks on nifedipine, PA as well as PNA increased slightly but returned to control values after 6 weeks of therapy. Plasma renin concentration, pANG II, pAldo and GFR did not change significantly. Renal sodium handling was also unchanged. It is concluded that long-term nifedipine therapy (exceeding 6 weeks) does not lead to activation of counter-regulatory mechanisms such as fluid retention, activation of the renin-angiotensin system and the adrenergic system. Renal function is unaffected by nifedipine.

Group I pepsinogens in serum. I. Normal range, age and sex relation, diurnal rhythm, seasonal variation, and distribution in ABO blood groups

The concentration of group I pepsinogens (PG I) in serum was determined in 235 healthy persons and hospital controls. The concentration was significantly higher in males. Correction of PG I with regard to body weight or lean body mass eliminated the sex difference but not the weak correlation with age. The normal range was 0.60-3.3 ng PG I/ml serum/kg body weight. For comparison with other PG I studies another normal range, 46-211 ng PG I/ml serum, was calculated as the 95% interpercentile range of the present PG I concentrations. In a study of diurnal rhythm and in a 6-month study of seasonal variation, no significant variation of PG I in serum was found. Serious non-gastric surgical disease did not influence the PG I level in serum. The PG I levels in blood groups O, A, and B did not differ significantly.

Placental steroid sulfatase deficiency: biochemical diagnosis and clinical review

Twenty-three cases of placental steroid sulfatase deficiency are reported. All children were boys who later acquired ichthyosis of the recessive X-linked type. The steroid sulfatase deficiency was present in placental tissue, umbilical cord leucocytes, and cultured skin fibroblasts of affected boys. An antepartum diagnosis can be obtained either by detecting the enzyme deficiency in cultured amniotic fluid cells or by finding an elevated total excretion of androstenetriol , 16 alpha-hydroxy-dehydroepiandrosterone, and 16 alpha-hydroxy-pregnenolone in maternal third-trimester urine. Vaginal delivery was accomplished in 16 patients (70%). No conspicuous pregnancy complications or neonatal problems were noted. However, birth weights tended to be relatively low. Intervention is unnecessary unless other obstetric indications require it. The incidence of this disorder appears to be approximately one per 2000 male births.

Testosterone treatment and arginine-induced growth hormone stimulation in male delayed puberty: effects on serum calcium, phosphate and vitamin D metabolites

Hormonal changes after arginine-induced growth hormone stimulation and subsequent testosterone treatment were examined in 5 patients classified as having male delayed puberty. All the patients responded well to growth hormone stimulation and a significant negative correlation was found between the delay in height age and the maximal growth hormone response, r = 0.80, P less than 0.05. The testosterone treatment did not alter this pattern. Changes in PTH, 25OHD, 24.25(OH)2D, and 1.25(OH)2D were examined at 24 h after the infusion. The results showed significant reductions in PTH (P less than 0.05) and 24.25 (OH)2D (P less than 0.05) and a possible increase in 1.25(OH)2D, whereas 25OHD remained unchanged. These results may support the conception of growth hormone as a common denominator of growth and bone metabolism.

Effects of natural oestrogen therapy on blood pressure and renin-angiotensin system in normotensive and hypertensive menopausal women

The blood pressure level and the renin-angiotensin system were investigated in 24 menopausal women (12 normotensive and 12 hypertensive) before, during and after six months of treatment with either oestradiol or trisekvens (sequential preparation containing oestradiol, oestriol and norethisterone acetate). In the normotensive women no significant alterations in systolic or diastolic blood pressure were found during treatment for six months. In the hypertensive women systolic blood pressure fell significantly during treatment with oestradiol as well as with trisekvens, while diastolic pressure did not change. All individual variations of blood pressure were small. The plasma concentrations of renin, angiotensin II and aldosterone remained unchanged during the treatments. A statistically significant increase in plasma renin substrate concentration was observed in all groups with the exception of the normotensive women treated with oestradiol. Menopausal symptoms in hypertensive women may safely be treated with natural oestrogens on the same indications as used for normotensive women.

Effects of amiloride on plasma and total body potassium, blood pressure, and the renin-angiotensin-aldosterone system in thiazide-treated hypertensive patients

Total body potassium content, plasma potassium concentration, blood pressure, and plasma concentrations of renin, angiotensin II, and aldosterone were measured in patients with essential hypertension after a run-in period of 8 wk on a regimen of hydrochlorothiazide (median dosage 75 mg/day). Patients were then randomly assigned to continued hydrochlorothiazide therapy (group I) or to receive adjunctive treatment with amiloride (group II, median dosage 15 mg/day or 5 mg per 25 mg hydrochlorothiazide) for the following 3 mo. There were no changes in group I patients during 3 mo on hydrochlorothiazide in plasma potassium, total body potassium content, or the renin-angiotensin-aldosterone system. Blood pressure was also unchanged. In group II patients addition of amiloride to hydrochlorothiazide induced a rise in plasma and total body potassium of approximately 15% and 4%. The potassium-retaining effect was maintained throughout the 12-wk period, although the maximal changes were observed after 8 wk of treatment. Supine blood pressure did not change, but there was a significant decrease in standing systolic blood pressure. There was a marked rise in plasma concentrations of renin, angiotensin II, and aldosterone.

Biochemical monitoring of vasoactive peptides during angiotensin converting enzyme inhibition

We present a brief survey of changes in vasoactive peptide systems during therapy with angiotensin converting enzyme inhibitors. Particular attention is paid to several methodological problems which are relevant to the clinical biochemistry and physiology of patients treated with this new type of drug.

An easy and reliable radioimmunoassay of serum androstenedione: age-related normal values in 252 females aged 2 to 70 years

A simple, non-chromatographic radioimmunoassay for the measurement of androstenedione (A-dione) in serum and based on a commercially available antiserum is described. The antibody-bound fraction was separated from the free fraction by a gel-centrifugation procedure. The method was used to establish reference values for normal females, based on determination in 252 normal females from 2 to 70 years of age. The data support the statement that the decline with age after puberty in the overall production of A-dione is mainly caused by a reduction in the adreno-derived A-dione, since the mean concentration of A-dione in age-matched pre- and postmenopausal women was very similar

Postpartum renal failure and malignant hypertension treated with captopril

A case of postpartum renal failure and malignant hypertension in a 24-year-old woman is reported. The condition occurred three weeks after caesarian section following a normotensive pregnancy. Treatment with a converting enzyme inhibitor, captopril, for one year normalized the blood pressure, with concurrent reduction of plasma angiotension II concentration and markedly improved glomerular filtration rate. It is suggested that activation of the renin-angiotensin system may cause the hypertension and impairment of renal function in postpartum renal failure, and that use of drugs blocking the renin system may be of particular clinical value in this situation.

Double-antibody solid-phase radioimmunoassay for blood bradykinin

A solid phase radioimmunoassay for the determination of blood bradykinin has been developed. Highly specific antibodies against bradykinin were raised in rabbits after coupling the peptide to thyroglobulin. Iodination of [Tyr8]-bradykinin was carried out with a chloramine-T procedure resulting in a tracer with high specific activity. Bradykinin was isolated in the following way: blood was sampled directly into acetone, and lipids were removed by extraction with petroleum either (40-60 degrees C). The final purification was made on QAE-Sephadex A-25 at pH 7.4. The mean recovery of added [125I-Tyr8]-bradykinin was 28% with a sample volume of 6 ml whole blood. The sensitivity of the radioimmunoassay was 1.25 pg/tube or 3 pg/ml blood. The reproducibility of the method is satisfactory with a between-assay coefficient of variation below 16%. Levels found in venous blood were below 3 pg bradykinin/ml in normal persons.

Heterozygotes and cryptic patients in families of patients with congenital adrenal hyperplasia (21-hydroxylase deficiency). HLA and glyoxalase I typing and hormonal studies

In a group of 18 unrelated Danish children with 21-hydroxylase deficiency (21-OH def.), human leukocyte antigen (HLA) typing revealed a significant increase of Bw47 and a significant decrease of B8. HLA studies of the families of 14 probands predicted among the siblings 11 heterozygote carriers and 3 genetically unaffected. Glyoxalase studies showed a recombination fraction of 8%. ACTH-stimulated 17-OH progesterone is the only hormone value useful in the discrimination between heterozygotes and normals. Two families are described in detail. In one family, one of two HLA-identical brothers had classical virilizing congenital adrenal hyperplasia (CAH), while the other was a normal boy without 21-OH def. In another family with 3 girls, one had classical, salt-wasting CAH, one had "late onset' CAH, and the third sister and the father shared the HLA-B14 antigen and were shown to have "cryptic' 21-OH def.