The effect of drug therapy on long-term outcome of childhood asthma: a possible preview of the international guidelines

BACKGROUND

International guidelines classify childhood asthma as mild, moderate, and severe and recommend treatment with "as needed" bronchodilators, cromolyn sodium, and inhaled corticosteroids, respectively. Recently, some investigators proposed inhaled corticosteroids as first-line therapy to avoid possible irreversible airway obstruction. This article describes a retrospective study assessing the effect of the guidelines' approach on the long-term outcome of childhood asthma and the possible effect of delaying initiation of administration of corticosteroids.

METHODS

A retrospective review was performed on the charts of 175 children, and an end-of-study questionnaire plus results of spirometry completed the data. The mean age at start of study was 6.5 years, and the children were followed up for 2.2 to 16.8 years (mean, 8.4 years). Treatments included bronchodilators as needed only (patients with mild asthma), cromolyn sodium (patients with moderate asthma), and inhaled corticosteroids (patients with severe asthma).

RESULTS

Frequency of symptoms, unscheduled doctors' visits, emergency department visits, hospitalizations, and missed school days decreased for the whole group. Statistically significant between-treatment differences favored both antiinflammatory therapies over as-needed bronchodilator treatment (cromolyn sodium: symptoms, p < 0.05; hospitalizations, p < 0.05; corticosteroids: emergency department visits, p < 0.05; hospitalizations, p < 0.05). Mean spirometry results improved, and the postbronchodilator values approached normal by study end. Assessed by treatment, spirometry decreased with bronchodilators but improved in patients treated with cromolyn sodium or inhaled corticosteroids. Delay in starting administration of cromolyn sodium had an unfavorable effect on clinical outcomes (p < 0.01) and spirometry (p < 0.05); delay in starting administration of corticosteroids did not.

CONCLUSIONS

Treatment with antiinflammatory drugs (cromolyn sodium or inhaled corticosteroids), but not as-needed bronchodilators alone, improves the long-term prognosis of asthma. It is possible that starting administration of nonsteroid antiinflammatory agents earlier than the present recommendations could further improve clinical outcomes, but prospective studies are needed.

Clinical effects of nedocromil sodium on challenges invoking neuronal mechanisms and on virally induced symptoms

Although sensory nerve activity may be important to the human airway in numerous possible ways, the relevance of "neurogenic inflammation" to the onset and development of asthma is unknown. However, several of the symptoms of asthma (bronchoconstriction, cough, and dyspnea) have a neuronal component that can be modeled in the laboratory by various stimuli that are thought to invoke sensory nerve activation. Nedocromil sodium is highly effective against bronchoconstriction induced by bradykinin, the tachykinins substance P and neurokinin A, and sulfur dioxide and metabisulfite. The results for induced cough in healthy subjects are equivocal, although the drug is effective on spontaneously occurring cough in patients with asthma. Nedocromil sodium had a modest but significant effect on symptoms associated with episodes of viral infection.

Effects of pancreas transplantation on distribution and composition of plasma lipoproteins

In type I (insulin-dependent) diabetic patients, peripheral hyperinsulinemia due to subcutaneous insulin treatment is associated with increased high-density lipoprotein (HDL) cholesterol, and also with an altered surface composition of HDL. Pancreas grafts also release insulin into the systemic rather than into the portal venous system, giving rise to pronounced peripheral hyperinsulinemia. We hypothesized that if peripheral hyperinsulinemia is responsible for high HDL cholesterol and/or altered surface composition of HDL in diabetic subjects, similar changes in the lipid profile should be present in pancreas-kidney transplant recipients (PKT-R). Using zonal ultracentrifugation, we isolated HDL2, HDL3, very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) from fasting plasma of 14 type I diabetic PKT-R, eight nondiabetic kidney transplant recipients (KT-R), and 14 healthy control subjects and determined the level and composition of the above lipoproteins. HDL2 cholesterol was increased in PKT-R as compared with KT-R and healthy controls (both P < .05), whereas HDL3 cholesterol was unchanged. However, an altered lipoprotein surface composition was evident in PKT-R: HDL2, HDL3, and LDL were enriched in unesterified cholesterol ([UC] PKT-R v KT-R, P=.13, P < .005, and P < .05, respectively; PKT-R v controls, all P < .005); HDL2 was enriched in phospholipids; and LDL was depleted of phospholipid. KT-R, in contrast, showed no changes in lipoprotein surface composition but a substantial triglyceride enrichment of HDL2 as compared with PKT-R and healthy controls (both P < .05). LDL size as determined by gradient gel electrophoresis was increased in PKT-R compared with controls (P < .005). The plasma concentration of cholesteryl ester (CE) transfer protein (CETP), involved also in phospholipid transfer, was increased in both transplant groups compared with healthy controls (both P < .05). Insulin concentrations in fasting plasma were directly related to CETP levels and to the weight-percentage of UC in HDL3, and inversely to the weight-percentage of phospholipids in LDL (all P < .05). We explain the increase in HDL2 cholesterol and LDL size in PKT-R by their high lipoprotein lipase (LPL) activity conferring an excellent capacity to clear chylomicron triglycerides. Effective handling of postprandial triglycerides, high HDL2 cholesterol, and predominance of LDL pattern A, respectively, are established indicators of a low risk of atherosclerosis. However, it is presently unclear what effects the compositional changes on the surface of HDL and LDL may have on cardiovascular risk in clinically stable PKT-R.

Acute renal failure complicating non-fulminant hepatitis A

Hepatitis, A is usually a mild and self-limiting infection of the liver. Whereas the clinical course is usually benign in children, complications such as prolonged cholestasis and fulminant liver failure have been reported in adults. Acute functional renal failure is an uncommon event in the absence of fulminating liver disease. So far, only cases of acute hepatitis A with biopsy-proven interstitial renal disease or tubular necrosis have been reported [Geltner et al. 1992. Kramer et al. 1986]. We present the case of a 35-year-old, previously healthy male with non-fulminant cholestatic viral hepatitis A, who developed progressive oliguric renal failure requiring dialysis therapy. Kidney biopsy ruled out glomerular disease and tubular necrosis. In the absence of bleeding and other causes of fluid depletion this case may be another variant of hepatorenal syndrome whose etiopathogenesis is only poorly understood.

Lipoprotein metabolism in renal replacement therapy: a review

Lipoprotein disorders are considered an important cause for the high cardiovascular morbidity and mortality in patients with end-stage renal disease and following renal transplantation. This article reviews the disease-associated changes of lipids and lipoproteins in these patients and, where known, the underlying causes and mechanisms. Further, we discuss the perturbed lipoprotein system in relation to the cardiovascular risk of patients on renal replacement therapy. Patients treated by hemodialysis are often hypertriglyceridemic with increased very low density lipoprotein (VLDL) levels and a type IV Frederickson pattern of hyperlipidemia. Total and LDL cholesterol concentrations are usually normal or subnormal. Treatment of end-stage renal disease by peritoneal dialysis results in increased total, VLDL and LDL cholesterol concentrations. Both treatment modalities are accompanied by a decrease of high density lipoprotein (HDL) cholesterol and apolipoprotein AI, whereas lipoprotein(a) [Lp(a)] concentrations are significantly elevated in both groups. Following renal transplantation a high incidence of hypercholesterolemia and hypertrigylceridemia is observed, which is attributed, at least in part, to the immunosuppressive therapy. Most patients normalize HDL cholesterol values and Lp(a) decreases to pre-disease plasma concentrations. Several studies have described elevated levels of cholesterol, triglycerides and Lp(a) in patients with cardiovascular complications during different phases of renal replacement therapy, which indicates a predictive (causative) role of these parameters for atherosclerotic diseases.

Synchronization of neuronal responses in the optic tectum of awake pigeons

Multiunit activity was recorded in the optic tectum of awake pigeons with two electrodes at sites varying in depth and separated by 0.3 to 3.0 mm. Autocorrelation and cross-correlation functions were computed from the recorded spike trains to determine temporal relationships in the neuronal firing patterns. Cross-correlation analysis revealed that spatially separate groups of cells in the tectum show synchronous responses to a visual stimulus. Strong synchronization occurred in both superficial and deep layers of the tectum, in general with zero-phase shift. The response synchronization in the avian optic tectum resembles that observed in the mammalian cortex, suggesting that it may subserve common functions in visual processing.

Role of reticular activation in the modulation of intracortical synchronization

During aroused states of the brain, electroencephalographic activity is characterized by fast, irregular fluctuations of low amplitude, which are thought to reflect desynchronization of neuronal activity. This phenomenon seems at odds with the proposal that synchronization of cortical responses may play an important role in the processing of sensory signals. Here, activation of the mesencephalic reticular formation (MRF), an effective way to "desynchronize the electroencephalogram," was shown to facilitate oscillatory activity in the gamma frequency range and to enhance the stimulus-specific synchronization of neuronal spike responses in the visual cortex of cats.

Integrator or coincidence detector? The role of the cortical neuron revisited

Neurons can operate in two distinct ways, depending on the duration of the interval over which they effectively summate incoming synaptic potentials. If this interval is of the order of the mean interspike interval or longer, neurons act effectively as temporal integrators and transmit temporal patterns with only low reliability. If, by contrast, the integration interval is short compared to the interspike interval, neurons act essentially as coincidence detectors, relay preferentially synchronized input, and the temporal structure of their output is a direct function of the input pattern. Recently, interest in this distinction has been revived because experimental and theoretical results suggest that synchronous firing of neurons might play an important role for information processing in the cortex. Here, we argue that coincidence detection, rather than temporal integration, might be a prevalent operation mode of cortical neurons. We base our arguments on established biophysical properties of cortical neurons and on particular features of cortical dynamics.

On the cerebro-protective effects of caroverine, a calcium-channel blocker and antiglutamatergic drug: double-blind, placebo-controlled, EEG mapping and psychometric studies under hypoxia

1. In a double-blind, placebo-controlled study, the acute antihypoxidotic properties of the calcium-channel blocking and antiglutamatergic caroverine were investigated utilizing blood gas analysis, EEG mapping and psychometry under a transient, reversible, hypoxic hypoxidosis. 2. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2) (found in 6000 m altitude), which was inhaled for 23 min under normobaric conditions by 16 healthy, young volunteers. They received randomized after an adaptation session, single oral doses of placebo, 40, 80 and 120 mg caroverine. Evaluation of blood gases, EEG mapping and psychometry were carried out 0, 2, 4, 6 and 8 h post-drug, during hypoxia. 3. Blood gas analysis demonstrated a drop in PO2 from 95 to 33 and 30 mmHg, in PCO2 from 38 to 30 and 30 mmHg in the 14th and 23rd minute of inhalation, respectively, while pH increased from 7.41 to 7.50 and 7.51. Base excess and standard bicarbonate remained stable. 4. EEG mapping under hypoxia exhibited a marked increase of delta/theta, decrease of alpha and an increase of superimposed beta activity, which reflects deterioration of vigilance. 5. Caroverine attenuated this hypoxia-induced vigilance decrement in a dose- and time-dependent manner 6-8 h after 80 mg and 2-8 h after 120 mg. 6. Hypoxic hypoxidosis induced a deterioration of memory and attention variability, which was mitigated by 80 and 120 mg caroverine. However, there was an augmentation of the hypoxia-induced decrement in psychomotor performance after 120 mg. 7. The drug was well tolerated, and there were no significant differences compared with placebo with regard to pulse and blood pressure.

Complement C4 phenotypes in patients with end-stage renal disease

The phenotypes of complement C4 were determined by agarose gel electrophoresis in 130 patients with end-stage renal failure of various causes and compared with those of 140 healthy controls. C4 allotype frequencies did not differ between patients and controls. Null alleles of both isotypes C4A and C4B were increased, but also without reaching significance. In type 1 diabetics an increased frequency of C4AQ0 (25 vs. 11.8%, p < 0.05) was found. Patients with two null alleles were far more frequent in the group with insulin-dependent diabetes mellitus (25 vs. 3.6%, p < 0.01). We confirmed the presence of a previously described uremic variant of C4B1. Additional uremic variants of C4 were detected in uremic patients homozygous for C4A3, B2 and B3. The relative electrophoretic migration values of the uremic variants of C4A3, B1, B2 and B3 were 132.1 +/- 2.9, 35.8 +/- 1.5, 70.4 and 73.9. These variants appear early in the course of chronic renal failure and disappear after successful renal transplantation. Uremic variants are the only acquired C4 phenotypes known so far. How uremia causes these variants remains unclear, but probably involves carbamylation of the C4 molecule.

Amantadine versus biperiden: a double-blind study of treatment efficacy in neuroleptic extrapyramidal movement disorders

Anticholinergic treatment of neuroleptic extrapyramidal movement disorders (EPS) has been associated with induction of tardive dyskinesia. Also an increasing abuse of anticholinergics by schizophrenic patients is noted. Since as early as 1976, positive effects of amantadine (AMA) on neuroleptic EPS have been described, therefore a controlled study of these reports seemed worthwhile. Forty-two schizophrenic patients (of which 7 were dropouts) of three centers entered the study and were treated for EPS in a double-blind design: 18 (11 m, 7 f) with AMA and 17 (8 m, 9 f) with biperiden (BIP). Identical preparations of AMA 100 mg, tid) and BIP (2 mg, tid) were used in treatment of haloperidol-induced EPS (AMA, mean 22.4 mg haloperidol; BIP, mean 19.6 mg haloperidol). Effects of treatment and possible side effects were rated: EPS for the intensity of EPS, BPRS for quantification of psychotic symptoms, FSUCL for rating the side effects and KUSTA to document patients' mood. Ratings were recorded on days 0, 3, 7, 14, 28 and at discontinuation, respectively. All patients were treated with haloperidol and levomepromazine (for tranquilization/sleep induction) and the respective antiparkinsonian agent for 14 days. Patient characteristics did not differ significantly in either groups. In the AMA treatment group, 2 patients dropped out for noncompliance, in the BIP group, 5 (3 no effect, 1 noncompliance, 1 agitation). All results as recorded with the different rating instruments showed a significant (p < 0.01) overall improvement, whereas no significant differences between treatment groups could be determined, notably the treatment effect of both drugs on EPS was similar. Thus, the application of AMA in cases of neuroleptic EPS seems justified and is a useful alternative of anticholinergic drugs. Certain advantageous aspects of AMA treatment of EPS with regard to the glutamate hypothesis of schizophrenia and tardive dyskinesia are discussed.

Transcranial magnetic stimulation: a novel antidepressive strategy?

Transcranial magnetic stimulation (TMS) is a well-established diagnostic probe in neurological practice. The increasing knowledge of biological mechanisms in electroconvulsive therapy presents a clear case for studying the applicability of TMS as a therapeutic tool in psychiatry. Based on the results of our pilot study showing a possible antidepressive effect of TMS, we conducted a controlled clinical trial on patients affected by major depression (DSM-III-R). Group 1 (n = 12) underwent TMS as add-on therapy to standard antidepressive medication, while group 2 (n = 12) was treated only with antidepressive medication. Already after the third add-on TMS session, a statistically significantly greater remission of depressive symptoms occurred in the patients of group 1 (p = 0.003). This statistically significant difference between the groups became even more marked on the last day of the study (p = 0.001, Wilcoxon). The results and further implications of TMS in psychiatric disorders are discussed.

Polymorphism of complement C4 and susceptibility to IDDM and microvascular complications

OBJECTIVE

The aim of this study was to investigate whether or not the inherited polymorphism of complement C4 is associated with genetic susceptibility to microvascular complications in IDDM as previously reported.

RESEARCH DESIGN AND METHODS

We determined C4 phenotypes in 241 patients with IDDM and 140 healthy control subjects by agarose gel electrophoresis and immunoprecipitation. C4 allotype frequencies were compared between patients and healthy control subjects. In addition, we compared allotype frequencies of 83 patients with nephropathy with those of 80 patients without nephropathy and compared those of 50 patients with proliferative retinopathy with those of 68 patients without retinopathy or background retinopathy. Duration of IDDM in control patients was at least 21 years.

RESULTS

Patients and healthy control subjects differed at both the C4A (P < 0.00001) and C4B (P < 0.0005) loci. The C4 null allele C4AQ0 was significantly increased in IDDM patients (26.8 vs. 11.8%, P < 0.005). C4B2 was more frequently observed in patients (14.5 vs. 6.8%, P < 0.05) compared with healthy control subjects. No differences were observed in C4 allotype distribution between patients with and without nephropathy or retinopathy.

CONCLUSIONS

These data confirm previous reports of an association between the C4 null allele C4AQ0 and IDDM. Our results do not support an association of the inherited polymorphism of complement C4 with genetic susceptibility to microvascular complications in patients with IDDM.

CD4 monoclonal antibody VIT4 in human alloimmune response in vitro and in vivo

In the present report the immunosuppressive effects of the murine anti-human CD4 monoclonal antibody (mAb) VIT4 on human alloimmune response in vitro were analyzed. Moreover, the antibody was tested for its activity to prolong allograft survival in seven patients with steroid-refractory allograft rejection. VIT4 inhibited the proliferative response to alloantigens in the mixed lymphocyte reaction (MLR) in a dose-dependent manner. At concentrations of 1 and 10 micrograms/ml VIT4 blocked MLR by 55 +/- 11% and 77 +/- 1%, respectively. Also alloantigen-specific proliferation of in vitro- generated memory T cells was dose-dependently reduced to 23 +/- 1% at a VIT4 concentration of 100 micrograms/ml. Furthermore, at the same dose level VIT4 blocked proliferation of antigen-specific short-term alloreactive CD4+ cell lines and significantly inhibited the in vitro generation of cytotoxic T lymphocytes (CTL). In a pilot study VIT4 (5 mg/d i.v.) was administered to 7 patients with steroid-refractory allograft rejection for 14 days. In 4 of 7 patients graft function transiently improved and graft survival in all patients was prolonged to a mean of 694 days (range 128-2163) from the beginning of the VIT4 treatment. In the light of our in vitro results and the preliminary clinical data, further clinical trials using higher antibody doses are greatly warranted to assess the efficacy of anti-CD4 mAb VIT4 in the treatment of allograft rejection.

Crystal structure of a bZIP/DNA complex at 2.2 A: determinants of DNA specific recognition

The X-ray structure of the GCN4-bZIP protein bound to DNA containing the ATF/CREB recognition sequence has been refined at 2.2 A. The water-mediated interactions between the basic domain and DNA are revealed, and combined with a more accurate description of the direct contacts, further clarify how binding specificity is achieved. Water molecules extend the interactions of both invariant basic domain residues, asparagine 235 and arginine 243, beyond their direct base contacts. The slight bending of the basic domain alpha-helix around the DNA facilitates the linking of arginine 241, 243 and 245 to main-chain carbonyl oxygen atoms via water molecules, apparently stabilizing interactions with the DNA.

The effect of nedocromil sodium on childhood asthma during the viral season

Viral-induced symptomatic respiratory infections (SRI) frequently cause exacerbations of asthma in children. This study investigated the protective effects of 0.5% nedocromil sodium nebulizer solution given three times a day in preventing asthma exacerbations associated with SRI. Ninety-three mild-moderate asthmatic children (6 to 12 yr of age) received either 0.5% nedocromil sodium or placebo for 24 wk during the viral season. The nedocromil sodium group was symptom-free 58% of the days, and the placebo-treated patients were symptom-free 45% of the days (p = 0.027). During Weeks 1-12, significant differences favored nedocromil sodium for asthma summary score (means: nedocromil sodium = 0.61, placebo = 0.92; p = 0.026), and daytime asthma (nedocromil sodium = 0.78, placebo = 1.22; p = 0.03). Significant differences were noted during monthly intervals for cough (Weeks 1-4: nedocromil sodium = 0.61, placebo = 0.92, p = 0.027) and peak expiratory flow rate (PEFR) (nedocromil sodium 262, placebo = 254 L/min, p = 0.041 Weeks 9-12). Patients in the active treatment group reduced their need for rescue inhaled beta 2-agonist by 10%, whereas patients treated with placebo demonstrated a 24% increase. There was a strong correlation between asthma symptoms and SRI symptoms (r = 0.47; p < 0.001). During SRIs, patients in the nedocromil sodium group demonstrated more rapid resolution of asthma symptoms immediately following infection (p = 0.033 summary score, p = 0.039 sleep difficulty). No serious adverse events were noted. Nedocromil sodium did not prevent the infection or exacerbation of asthma symptoms during SRI.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of the timing and the administration of acarbose on postprandial hyperglycaemia

To clarify the optimum timing for ingestion of acarbose, a 100 mg dose of this oral hypoglycaemic agent was administered 30 min before, at the beginning, and 15 min after ingestion of a test meal, and the effects of the drug on blood glucose rises were compared with increases observed after a control meal (no drug). Twenty-four patients with Type 2 diabetes were included in a randomized, open, cross-over study. The smallest increases in blood glucose (p < 0.001) occurred when acarbose was taken at the beginning and 15 min after starting the test meal (3.3 +/- 1.6 mmol l-1 and 3.3 +/- 1.4 mmol l-1). The increase in blood glucose levels when acarbose was taken 30 min before the test meal was significantly higher (4.2 +/- 1.8 mmol l-1) and it was at its maximum following the control meal (5.2 +/- 1.7 mmol l-1). Similar results were observed when the effects of acarbose on insulin and C-peptide levels were measured. It is recommended that patients should be instructed to take acarbose with their first mouthful of food.

Symptom outcome after functional endoscopic sinus surgery in patients with cystic fibrosis: a prospective study

Twenty-nine consecutive patients with cystic fibrosis were offered functional endoscopic sinus surgery. Twenty-six of these patients underwent surgery. A symptom questionnaire was obtained from the patient or parent before surgery. At the end of the study this symptom questionnaire was again administered to the same individual, and 21 completed it. There were 14 male and 7 female patients, with a mean age of 12.3 years and a median age of 8.7 years. Mean follow-up was 34.3 months. Results for the following symptoms were significant: nasal airway obstruction was improved (p < 0.0002), olfactory function was improved (p < 0.0037), purulent nasal discharge was decreased (p < 0.001), and activity level was increased (p < 0.001). Other parameters are also reported in the text. In summary, this study prospectively studies the effects of functional endoscopic sinus surgery on symptoms in patients with cystic fibrosis. The study points out several significant areas of symptom improvement and supports the selective use of functional endoscopic sinus surgery in patients with cystic fibrosis. Indications for surgery are provided.

Influence of various heparin preparations on lipoproteins in hemodialysis patients: a multicentre study

Recent studies have indicated controversial effects of low molecular weight heparin (LMWH) on lipid metabolism in patients on chronic hemodialysis as compared to unfractionated heparin (UFH). We therefore conducted a cross-sectional multicentre study comparing 153 patients treated with LMWH and 153 patients with UFH, matched for sex, age and diabetes mellitus. Both groups have been treated with LMWH or UFH for six months or longer (14.9 vs. 23.4 months). We observed no differences between the UFH and LMWH treatment groups for total cholesterol, LDL cholesterol, triglycerides, apoB, apoA-IV or Lp(a). The only significant differences were seen for HDL cholesterol and the corresponding apolipoprotein apoA-I, which were significantly higher in the UFH group (HDL cholesterol: 0.97 +/- 0.35 mM/l vs. 0.87 +/- 0.37 mM/l, p < 0.05; apoA-I 1.23 +/- 0.27 g/l vs. 1.15 +/- 0.27 g/l, p < 0.05). We conclude that the results of studies investigating the influence of LMWH on lipid metabolism are as heterogeneous as the substances themselves. This challenges the beneficial influence supposedly had by LMWH preparations on lipid metabolism.

Short-term and long-term effects of albuterol aerosol therapy in cystic fibrosis: a preliminary report

The effectiveness of maintenance albuterol aerosol therapy in cystic fibrosis (CF) was assessed by comparing spirometric measurements at the beginning and end of 1 year. Peak expiratory flow rates (PEFR) were measured twice daily to determine bronchodilator responsiveness and spontaneous diurnal variation (SDV), and results were compared with groups of normal and asthmatic children. CF patients not receiving regular albuterol therapy served as a control group. In the treatment group, forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) were significantly increased (12.2% and 18.4%, respectively) over the course of the treatment year, as contrasted with a significant decrease during the preceding year. During the study year the CF control group had a significant decrease in FEV1 and FEF25-75%, and the difference between treatment and control groups was significant for FVC, FEV1, and FEF25-75%. PEFR increased from the first to the last week of the year-long observation period (from 71.8% to 78.7% of predicted values, P < 0.01). Spontaneous diurnal variations were significantly greater in the CF study group than a group of normal children; SDV decreased significantly in the treatment group during the year of study. A bronchodilator response of > 15% was present in 25.8% of CF patient days, but there was considerable interpatient variability. Frequent bronchodilator responders were accurately predicted by their baseline bronchodilator responsiveness, but not by age or personal or family history of asthma or atopy. No difference in long-term pulmonary function improvements were noted between frequent and infrequent responders. The results suggest that maintenance albuterol aerosol treatments reversed the progressive downward course in lung function in the CF treatment group. A double-blind placebo-controlled study is required to confirm these preliminary findings.

Symptom Outcome After Functional Endoscopic Sinus Surgery in Patients with Cystic Fibrosis: A Prospective Study

Twenty-nine consecutive patients with cystic fibrosis were offered functional endoscopic sinus surgery. Twenty-six of these patients underwent surgery. A symptom questionnaire was obtained from the patient or parent before surgery. At the end of the study this symptom questionnaire was again administered to the same individual, and 21 completed it. There were 14 male and 7 female patients, with a mean age of 12.3 years and a median age of 8.7 years. Mean follow-up was 34.3 months. Results for the following symptoms were significant: nasal airway obstruction was improved ( p < 0.0002), olfactory function was improved ( p < 0.0037), purulent nasal discharge was decreased ( p < 0.001), and activity level was increased ( p < 0.001). Other parameters are also reported in the text. In summary, this study prospectively studies the effects of functional endoscopic sinus surgery on symptoms in patients with cystic fibrosis. The study points out several significant areas of symptom improvement and supports the selective use of functional endoscopic sinus surgery in patients with cystic fibrosis. Indications for surgery are provided.

Correlated firing in sensory-motor systems

Traditionally, synchronous firing of neurons has been considered to be an epiphenomenon of neuronal networks, reflecting particular properties of circuitry, but having no functional relevance. In the past few years, an alternative view has been advocated, which suggests that temporal correlations serve a role in information processing by expressing relations among the responses of distributed neurons. This hypothesis has received experimental support from recent in vivo studies performed on the sensory systems of a variety of species. These results support earlier proposals that correlated activity might have an important function in sensory-motor integration and memory.

Multicenter study of lipoprotein(a) and apolipoprotein(a) phenotypes in patients with end-stage renal disease treated by hemodialysis or continuous ambulatory peritoneal dialysis

Numerous studies have investigated lipoprotein(a) (Lp(a)) plasma concentrations in patients with ESRD, a patient group with an enormous risk for atherosclerosis. The reported differences in Lp(a) between controls and patients vary from a decrease of 49% to an increase of more than 1,000%. However, data are not consistent, mostly because of problems with statistical analysis, and only limited data are available for patients treated by continuous ambulatory peritoneal dialysis (CAPD). To estimate the significance of Lp(a) in ESRD and to demonstrate the statistical pitfalls concerning Lp(a) in case-control studies, a large multicenter study including 702 patients treated by either hemodialysis (HD) (N = 534) or CAPD (N = 168) was conducted, and results were compared with results from 256 healthy controls. Both patient groups showed significantly elevated Lp(a) levels in comparison with controls: 23.4 +/- 25.0 mg/dL (P < 0.005; HD) and 34.6 +/- 38.4 mg/dL (P < 0.0001; CAPD) versus 18.4 +/- 22.8 mg/dL (controls). CAPD patients showed significantly higher Lp(a) values than did patients treated by HD (P < 0.001). The difference between the two treatment groups possibly reflects an overproduction of Lp(a) to compensate for protein losses in CAPD patients. Both treatment groups included significantly more patients with Lp(a) values greater than the 75th percentile (25.6 mg/dL) of the control group (33.9 and 41.7% for HD and CAPD, respectively; P < 0.005). The higher Lp(a) values in patients were not explained by differences in isoform frequencies and the increase in Lp(a) was apolipoprotein(a) type specific: only patients with high-molecular-weight apolipoprotein(a) isoforms showed a significant elevation in Lp(a) levels. The increased plasma concentrations of Lp(a) may contribute to the high risk for atherosclerosis in ESRD, especially in patients treated by CAPD. Finally, it is believed that small sample sizes are responsible for the diverging results in Lp(a) literature.

Low molecular weight heparin does not necessarily reduce lipids and lipoproteins in hemodialysis patients

Recent studies have indicated a beneficial effect of one particular low molecular weight heparin preparation (Fragmin) on lipid metabolism in patients on chronic hemodialysis as compared to unfractionated heparin. We conducted a prospective crossover study with paired comparison of two different anticoagulant agents to examine the effects of a recently released new low molecular weight heparin (Sandoparin) on lipid and lipoprotein parameters in 24 patients starting hemodialysis. During the first six months of observation patients received Sandoparin. Then patients were switched to unfractionated heparin and observed for further six months. After switching from Sandoparin to unfractionated heparin we observed significant decreases in total cholesterol (from 168.6 +/- 42.2 to 154.4 +/- 41.9 mg/dl, p < 0.02), LDL cholesterol (from 106.4 +/- 35.2 to 89.9 +/- 32.3 mg/dl, p < 0.005), triglycerides (from 148.7 +/- 85.0 to 121.4 +/- 88.8 mg/dl, p < 0.05) and apolipoprotein B (from 100.0 +/- 35.3 to 89.9 +/- 30.4 mg/dl, p < 0.05) and a significant increase in HDL cholesterol (from 32.8 +/- 12.5 to 37.7 +/- 17.5 mg/dl, p < 0.02). This is in contrast to earlier results and can possibly be explained by a higher percentage of fractions with high M(r) in the investigated Sandoparin, which results in a more pronounced depletion of lipoprotein lipase. Together with the enhanced hepatic clearance of lipoprotein lipase induced by low molecular weight heparins, this may decrease lipoprotein lipase activity with a subsequent increase in plasma triglycerides, total and LDL cholesterol. We conclude from our data that a general recommendation for clinical use of low molecular weight heparin in hemodialysis patients cannot be given.

How precise is neuronal synchronization?

Recent work suggests that synchronization of neuronal activity could serve to define functionally relevant relationships between spatially distributed cortical neurons. At present, it is not known to what extent this hypothesis is compatible with the widely supported notion of coarse coding, which assumes that features of a stimulus are represented by the graded responses of a population of optimally and suboptimally activated cells. To resolve this issue we investigated the temporal relationship between responses of optimally and suboptimally stimulated neurons in area 17 of cat visual cortex. We find that optimally and suboptimally activated cells can synchronize their responses with a precision of a few milliseconds. However, there are consistent and systematic deviations of the phase relations from zero phase lag. Systematic variation of the orientation of visual stimuli shows that optimally driven neurons tend to lead over suboptimally activated cells. The observed phase lag depends linearly on the stimulus orientation and is, in addition, proportional to the difference between the preferred orientations of the recorded cells. Similar effects occur when testing the influence of the movement direction and the spatial frequency of visual stimuli. These results suggest that binding by synchrony can be used to define assemblies of neurons representing a coarse-coded stimulus. Furthermore, they allow a quantitative test of neuronal network models designed to reproduce physiological results on stimulus-specific synchronization.

Acute central effects of the calcium channel blocker and antiglutamatergic drug caroverine. Double-blind, placebo-controlled, EEG mapping and psychometric studies after intravenous and oral administration

In a double-blind, placebo-controlled study, the effects of caroverine (CAS 23465-76-1, Spasmium)--a quinoxaline derived from isoquinoline, the basic structure of papaverine, originally developed as a spasmolytic drug which may, however, exert central effects due to an unspecific calcium channel blocking action and glutamate antagonism--were investigated utilizing EEG-mapping, psychometric and psychophysiological measures. Fifteen healthy volunteers (8 males and 7 females), aged 20-35 years, received randomized and at weekly intervals 40 and 80 mg caroverine intravenously, 40 and 80 mg caroverine orally, as well as placebo. EEG recordings, psychometric and psychophysiological tests, as well as evaluation of pulse, blood pressure and side-effects were carried out at 0, 1, 2, 4, 6 and 8 h. Multivariate analysis of EEG mapping data demonstrated that caroverine exerted a significant action on human brain function, as compared with placebo, at all given dosages, as early as in the 1st and as late as in the 8th hour after both intravenous and oral administration during resting (R-EEG) and vigilance-controlled recording (V-EEG). Subsequent univariate analyses revealed, however, differential effects of caroverine--dependent on recording conditions and doses. In the resting condition, an increase of absolute and relative delta and theta power, a decrease of alpha and beta power and a slowing of the centroid of the delta and theta activity occurred, reflecting sedative action. The latter was slightly time- and dose-dependent (more sedation in earlier hours after higher doses). However, in the vigilance-controlled EEG, a dose-dependent decrease of delta and theta power, an increase of alpha power and an acceleration of the centroid of the delta and theta suggested vigilance-promoting effects, which were more pronounced in the later than earlier hours. Psychometric investigations confirmed these differential central effects. In regard to the noopsyche, an improvement was noted 6 h after the lowest oral dose. In the thymopsyche, a deterioration occurred after all doses except the highest oral dose, suggesting sedation. The latter was also seen after all active compounds as a trend in psychophysiological variables. The drug was well tolerated.

Clinical overview of nedocromil sodium

Nedocromil sodium is a novel anti-inflammatory agent that has been demonstrated to significantly improve pulmonary function and decrease bronchial hyperreactivity in asthmatic patients. Currently available only as an inhaled drug, nedocromil sodium has an excellent safety profile, the only adverse effect being a slightly unpleasant taste. Nedocromil sodium has been used as a replacement for sustained-release theophylline therapy; the overall efficacy of nedocromil sodium is at least equivalent to that of theophylline, with less adverse effects occurring in those patients treated with nedocromil sodium rather than with theophylline. Nedocromil sodium also appears to be equal in efficacy to low doses of beclomethasone when employed in patients with mild to moderate asthma. Addition of nedocromil sodium to an ongoing regimen of beclomethasone may also allow for reduction in the dosage of inhaled corticosteroid. The overall safety of therapy with nedocromil sodium suggests that it be considered as initial therapy for those patients having mild to moderate asthma.

New NO-donors with antithrombotic and vasodilating activities, XII: Mesoionic oxatriazoles and related noncyclic nitrosohydrazine derivatives

Mesoionic 1,2,3,4-oxatriazolimines and the corresponding oxatriazolones were prepared and tested for their antiplatelet and antithrombotic activities. In the Born-test 5-amino-3-phenyl-1,2,3,4-oxatriazolimine chloride inhibited the platelet aggregation halfmaximally in a concentration of 50 nmol/L. Its N-ethoxycarbonyl derivative inhibited thrombus formation in arterioles of rats by 48% (10 mg/kg, 2 h after p.o. administration). These effects appear to be related to the formation of intermediate nitrosohydrazine derivatives. This aspect was supported by the activities in noncyclic nitrosohydrazines (2 compds.), nitrosohydrazones (2) and nitrosohydrazides (11). Five of them exhibited an IC50 < 100 nmol/L in the Born-test. In a thrombotic model strong inhibition of thrombus formation was observed after intravenous application. The 1-nitroso-1-benzylhydrazine even exhibited strong inhibitory effects after oral administration.

Relation between oscillatory activity and long-range synchronization in cat visual cortex

Recent theoretical studies have suggested that oscillatory firing patterns with frequencies in the gamma band (30-70 Hz) may be instrumental for the establishment of synchrony among widely distributed neurons if synchrony is to be achieved by reciprocal connections. We have now investigated the relationship between synchrony and oscillations in cat visual cortex. Our results show that when synchronization of neuronal activity occurs over distances of > 2 mm in primary visual cortex, or occurs between the two hemispheres, it is almost always associated with oscillatory firing patterns, whereas synchronization over short distances occurs also in the absence of oscillations. Furthermore, our results indicate that short-range interactions affect both the firing rate of the respective neurons and the timing of their discharges, whereas only the latter is influenced by long-range interactions. These data support the hypothesis that oscillatory activity can contribute to the establishment of long-range synchrony in a network of reciprocally coupled neurons.

Changes of carbohydrate-deficient transferrin in chronic alcoholism

Compared with other well established liver enzyme parameters, carbohydrate-deficient transferrin (CDT) offers a new method for the identification of chronic alcoholism. The dependence of CDT and alcoholism/abstinence was studied in 29 controls and 64 alcoholics (both groups comprising men and women). In contrast to the currently used parameters GOT, GPT, gammaGT, LDH and MCV, CDT measures chronic alcoholism exclusively. CDT is dependent on sex but not age. In chronic alcoholism its rate increases significantly, but drops quickly after a short time of abstinence. CDT variations may be a specific and sensitive indicator of alcoholism or abstinence and possibly the duration.

Alpha 1-antitrypsin phenotypes in patients with anti-neutrophil cytoplasmic antibody-positive vasculitis

1. The genetic background of anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis remains largely unknown. Recently a very high prevalence of medium and severe deficiency of alpha 1-antitrypsin was described in a small group of patients with Wegener's granulomatosis and c-ANCA. c-ANCAs are autoantibodies against proteinase 3, and alpha 1-antitrypsin is the main inhibitor of this enzyme. 2. alpha 1-Antitrypsin phenotypic polymorphism was determined by isoelectric focusing in 32 patients with c-ANCA-associated systemic vasculitis. Twenty-nine patients had Wegener's disease, two had microscopic polyarteritis and one suffered from idiopathic rapidly progressive glomerulonephritis. 3. Two patients were homozygous PiZZ and three were heterozygous PiMZ. These phenotype frequencies differed significantly from expected values, assuming Hardy-Weinberg equilibrium (P < 0.01). Compared with a control group of 868 healthy blood donors, these results meant a significant increase in the PiZ allele (0.0138 versus 0.1094, P < 0.001). 4. Furthermore, the serum of 47 patients with severe alpha 1-antitrypsin deficiency (PiZZ) was tested for the presence of ANCA. All sera were negative for c-ANCA and p-ANCA. None of the patients showed clinical signs of systemic vasculitis. 5. In conclusion, these data indicate that alpha 1-antitrypsin deficiency, despite being significantly more common in patients with c-ANCA-associated systemic vasculitis, is only a minor genetic risk factor for the development of this disease.

Reduced synchronization in the visual cortex of cats with strabismic amblyopia

Synchronous firing of spatially separate neurons was studied with multi-electrode recordings in area 17 of the visual cortex of strabismic cats which had developed behaviourally verified amblyopia of the deviated eye. Responses of neurons were evoked with moving light bars or gratings of different spatial frequency. Neurons driven by the normal eye displayed stronger synchronization of their responses than neurons dominated by the amblyopic eye. These interocular differences were highly significant and particularly pronounced for grating stimuli of high spatial frequency. No interocular differences were noted with respect to the amplitudes of responses to the light bars and gratings. These results suggest reduced synchronization of population responses as a neurophysiological correlate of strabismic amblyopia and underline the importance of correlated firing of spatially separate cortical neurons for normal processing of visual information.

Effect of pancreas transplantation on lipoprotein lipase, postprandial lipemia, and HDL cholesterol

Pancreas transplantation with systemic venous drainage of the graft causes elevated plasma levels of insulin, known to be a potent regulator of plasma lipoprotein metabolism. We studied 11 post-type I diabetic pancreas-kidney transplant recipients, 9 type I diabetic kidney transplant recipients displaying peripheral hyperinsulinemia due to subcutaneous insulin treatment, 11 nondiabetic kidney transplant recipients as controls for the effects of immunosuppressive medication, and 11 healthy control subjects, all matched for age, sex, and body mass index. We determined fasting lipids, lipoproteins and lipolytic enzymes, as well as postprandial lipid metabolism after a standardized oral fat load. High-density lipoprotein (HDL) cholesterol averaged 1.98 (0.40) mmol/L in pancreas-kidney transplant patients, clearly higher than that of kidney transplant recipients (1.52 (0.36) mmol/L, P < 0.05) or of controls (1.50 (0.38) mmol/L, P < 0.05). In pancreas-kidney transplant patients postprandial lipemia was lowest and lipoprotein lipase activity was highest (average 32% and 154%, respectively, of the mean of the controls) compared with nondiabetic kidney transplant recipients (P < 0.005, P < 0.05) and healthy controls (P < 0.001, P < 0.01). In type I diabetic kidney transplant recipients the levels of HDL cholesterol (1.88 (0.63) mmol/L), postprandial lipemia, and lipoprotein lipase activity were intermediate between pancreas-kidney transplant patients and healthy controls. The distinctly elevated HDL cholesterol in pancreas-kidney transplant patients can be readily explained by the low postprandial triglyceride levels resulting from a high activity of lipoprotein lipase. The very favorable lipid profile in post-diabetic pancreas-kidney transplant recipients could be expected to counteract the severe atherosclerotic risk of long-standing diabetes.

A method for the quantification of synchrony and oscillatory properties of neuronal activity

Interactions between neurones can be analysed by simultaneously recording from several cells and computing correlation functions between the respective activities. Recent studies have revealed that neuronal responses are often synchronous and exhibit an oscillatory temporal structure. These two properties are commonly assessed together from correlation functions. In order to evaluate these variables independently a method was devised for the quantification of a generalized Gabor function that was fitted to the correlograms. The performance of the method was tested on a large data set from cat area 17 and its stability was examined with respect to its dependence on the number of free parameters. The results demonstrate that the proposed fitting algorithm is robust in that it is rather independent of starting conditions and converges to optimal fits even with different settings of free variables. The fitted correlation function allow for an automatic and independent classification of synchrony on the one hand and oscillatory firing patterns on the other.

Apolipoprotein(a) phenotype-associated decrease in lipoprotein(a) plasma concentrations after renal transplantation

High lipoprotein(a) [Lp(a)] plasma concentrations are an independent risk factor for atherosclerosis. In the general population, Lp(a) levels are primarily determined by allelic variation at the apolipoprotein(a) [apo(a)] gene locus. Apo(a) isoforms of various sizes are associated with different Lp(a) concentrations. Patients with end-stage renal disease (ESRD) have elevated plasma concentrations of Lp(a), which are not explained by the size variation at the apo(a) gene locus. To further investigate the origin of the elevated Lp(a) plasma concentrations, we examined Lp(a) concentrations and apo(a) phenotypes in 154 ESRD patients undergoing renal transplantation. In a prospective longitudinal study we observed a rapid normalization of Lp(a) levels from an average concentration of 25.9 +/- 28.7 mg/dL before to 17.9 +/- 25.5 mg/dL 3 weeks after renal transplantation (P < .0001). Only patients with high-molecular-weight phenotypes had a significant decrease in Lp(a) plasma concentrations. This study demonstrates the nongenetic origin of elevated Lp(a) concentrations in ESRD patients, which is obviously caused by the disease. It further confirms a phenotype-associated elevation of Lp(a) concentrations in ESRD.

Parental management of infants born following a cot-death victim who were monitored compared to infants who, despite similar histories, were not monitored: a controlled study

We studied 93 families who had previously lost a baby to cot-death. Of these, 31 chose cardiorespiratory monitoring (CRM) for their next child and were compared to 62 families who, despite similar histories, decided not to monitor their subsequent infant. A control group consisted of 50 families without history of cot death. The three objectives of this retrospective study were: (1) to gain insight into psychological factors which differentiate between parents who insist on monitoring their infant and those who do not; (2) to explore how parents of both groups cope with their feelings of anxiety and stress and; (3) to examine the effect of psychological factors on parental reactions to monitor alarms. Infants of the monitor group and the nonmonitor group were matched to the age reached by the previous cot-death victims at the moment of death. Parents who had experienced cot-death (91%) and 37% of the control group parents completed the State-Trait Anxiety Inventory (STAI) and a questionnaire, consisting mainly of multiple-choice questions. Results show that monitor parents and nonmonitor parents differ greatly in their expectations of and attributions to the equipment and in the way they process information about monitoring. More monitor parents attribute a protective value to CRM. Monitor parents reported to have been more stressed during pregnancy. Postnatally, monitor parents and nonmonitor parents did not experience different anxiety levels. Nonmonitor parents experienced a slight decrease of feelings of happiness over time. Mothers with high state anxiety scores noted more false bradycardia alarms than mothers with low scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein(a) phenotypes predict the risk for carotid atherosclerosis in patients with end-stage renal disease

Several studies have demonstrated that atherosclerotic complications are the major cause of morbidity and mortality in hemodialysis patients. High lipoprotein(a) [Lp(a)] plasma concentrations are an independent risk factor for atherosclerosis. Patients with end-stage renal disease (ESRD) have elevated plasma concentrations of Lp(a), which are not explained by size variation at the apolipoprotein(a) [apo(a)] gene locus. The aim of our study was to investigate whether Lp(a) concentrations and/or apo(a) phenotypes are predictive of the degree of atherosclerosis in the extracranial carotid arteries in ESRD patients. Of 167 patients, 108 showed atherosclerotic plaques (65%). Univariate analysis showed that the plaque-affected group was significantly older and had a higher frequency of angina pectoris, previous myocardial infarction, or cerebrovascular accident. Furthermore, this group included significantly more patients with low-molecular-weight apo(a) isoforms (26.9% versus 8.5%, P < .005) and had significantly higher mean Lp(a) plasma concentrations (29.3 +/- 31.0 versus 19.7 +/- 25.7 mg/dL, P < .05). Lp(a) plasma concentration increased significantly with the number of affected arterial sites, from 19.7 mg/dL in patients without plaques to 40.1 mg/dL in patients with seven or eight affected sites. In patients with low-molecular-weight phenotypes, significantly more arterial sites were affected (3.62 versus 2.08, P < .001). Multivariate regression analysis showed that age, angina pectoris, and the apo(a) phenotype were the only significant predictors of the degree of atherosclerosis. We conclude that, besides age, the apo(a) phenotype is the best predictor of carotid atherosclerosis in ESRD patients and may be used for assessment of general atherosclerosis risk in this patient group.

A multicenter double-blind trial of paroxetine versus amitriptyline in depressed inpatients

The phenylpiperidine derivative paroxetine is a selective serotonin reuptake inhibitor. In a double-blind 6-week trial, paroxetine was compared with amitriptyline in hospitalized patients suffering from major depression (DSM-III). One hundred fifty-three patients were enrolled in the study in seven centers in Austria and Germany. Results showed similar efficacy of both drugs after 6 weeks. The differences between groups in Montgomery-Asberg Depression Rating Scale and Clinical Global Impression ratings did not reach statistical significance at any time. Side effects were distributed similarly but with a significantly higher incidence of anticholinergic effects in patients treated with amitriptyline (p < or = 0.001), whereas agitation and insomnia were registered more often in the paroxetine group. This study supports the antidepressive efficacy of paroxetine in a sample of severely depressed inpatients.

Effect of sample storage on the measurement of lipoprotein[a], apolipoproteins B and A-IV, total and high density lipoprotein cholesterol and triglycerides

This study investigated the influence of long-term storage, for periods up to 24 months, and multiple freezing and thawing on the measured values of lipoprotein[a] (Lp[a]), apolipoproteins B and A-IV, total and high density lipoprotein (HDL) cholesterol and triglycerides using plasma samples stored at -80 degrees C, -20 degrees C, and 4 degrees C. Samples stored at -80 degrees C or -20 degrees C showed significant changes in Lp[a] after 24 months, with a mean decrease of 7% and 13%, respectively (P < 0.01). The major part of the decrease occurred during the first freezing and thawing. In contrast, apolipoproteins B and A-IV decreased continuously over time (P < 0.05). The increase in plasma concentrations of total and HDL cholesterol and triglycerides was small but significant because of its uniformity. Multiple freezing and thawing influenced only the measured values of Lp[a] and apolipoprotein B. Comparison of samples stored at -80 degrees C and -20 degrees C showed no difference in any of the parameters at any time with the exception of Lp[a] after 18 and 24 months (P < 0.05). After a storage period of 24 months, immunoblotting with detection of apo[a] was possible from samples under each storage condition. ApoB and apoA-IV were detectable only in samples stored at -20 degrees C or -80 degrees C. These data, when compared to recent studies, suggest a critical role of the assay methodology in the reproducibility of measured Lp[a] and apolipoprotein plasma concentrations. We therefore recommend the examination of each system for measurement of long-term stored plasma samples.

Clinical significance of urinary cyclic guanosine monophosphate in diagnosis of heart failure

We measured concentrations of guanosine 3',5'-monophosphate (cGMP) in plasma and urine of healthy subjects and patients with congestive heart failure, renal impairment, neoplastic disease, and hepatic cirrhosis. There was no correlation between cGMP concentrations in urine and in plasma. In all patients except those with renal impairment, urinary cGMP concentrations were significantly higher than in healthy persons. Only patients with heart failure or renal impairment showed significantly increased plasma cGMP concentrations. In contrast, cGMP in urine does not relate to the clinically assessed severity of heart failure (New York Heart Association functional classes). Determination of cGMP in plasma results in higher sensitivity and specificity for diagnosing heart failure than measurement of cGMP in urine.