Mutations in the mineralocorticoid receptor gene cause autosomal dominant pseudohypoaldosteronism type I

Pseudohypoaldosteronism type I (PHA1) is characterized by neonatal renal salt wasting with dehydration, hypotension, hyperkalaemia and metabolic acidosis, despite elevated aldosterone levels. Two forms of PHA1 exist. An autosomal recessive form features severe disease with manifestations persisting into adulthood. This form is caused by loss-of-function mutations in genes encoding subunits of the amiloride-sensitive epithelial sodium channel (ENaC; refs 2,3). Autosomal dominant or sporadic PHA1 is a milder disease that remits with age. Among six dominant and seven sporadic PHA1 kindreds, we have found no ENaC gene mutations, implicating mutations in other genes. As ENaC activity in the kidney is regulated by the steroid hormone aldosterone acting through the mineralocorticoid receptor, we have screened the mineralocorticoid receptor gene (MLR) for variants and have identified heterozygous mutations in one sporadic and four dominant kindreds. These include two frameshift mutations (one a de novo mutation), two premature termination codons and one splice donor mutation. These mutations segregate with PHA1 and are not found in unaffected subjects. These findings demonstrate that heterozygous MLR mutations cause PHA1, underscore the important role of mineralocorticoid receptor function in regulation of salt and blood pressure homeostasis in humans and motivate further study of this gene for a potential role in blood pressure variation.

Emerging molecular cytogenetic technologies

Fluorescent in situ hybridization (FISH) as an adjunct technique to conventional banding techniques has been firmly established in the past few years. The many clinical and research applications of FISH include chromosome enumeration using alpha-satellite probes, marker identification, gene mapping and 'chromosome painting' in the delineation of complex structural chromosomal abnormalities. Comparative genomic hybridization (CGH) is a relatively new FISH-based technique which can detect gains and losses of whole chromosomes and subchromosomal regions. Like CGH, which can scan the whole genome without prior knowledge of specific chromosomal abnormalities, spectral karyotyping (SKY) confers on each chromosome a distinct colour to enable identification of even cryptic chromosomal rearrangements. The present paper introduces and summarizes these emerging molecular cytogenetic techniques.

Mechanism of capillary electrophoresis enantioseparations using a combination of an achiral crown ether plus cyclodextrins

The addition of an achiral crown ether (18-crown-6) to a cyclodextrin-based separation can significantly affect the capillary electrophoresis (CE) enantioresolution of organic racemates that contain a primary amine functional group. In most cases an enhancement of the enantioseparation was observed. However, there are also cases where the addition of 18-crown-6 was detrimental to a cyclodextrin-based CE enantioseparation. The effect of concentration of the two complexing additives as well as the effect of pH and added potassium ion were examined. A specific three-body complex involving simultaneous, dual inclusion complex formation can be used to explain both the enhanced and diminished enantioselectivities observed when 18-crown-6 is added to the run buffer.

Inhibitory actions of emodin on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori, a gram-negative rod bacteria collected from peptic ulcer patients. The NAT activity was determined using a acetyl CoA recycling assay and HPLC. Cytosols or suspensions of H. pylori with and without selected concentrations of emodin co-treatment showed different percentages of 2-aminofluorene and p-aminobenzoic acid acetylation. The data indicate that there were decreased NAT activity associated with increased emodin in H. pylori cytosols. As 400 microns of emodin can obviously inhibit NAT activity both in vitro and in vivo (inhibition rate 90% and 93% for 2-aminofluorene and p-aminobenzoic acid in vitro, and 90% and 92%, respectively, for both substrate in vivo). For in vitro examination, the apparent values of Km and Vmax were 3.12 +/- 0.38 mM and 15.20 +/- 3.16 nmol/min/mg protein for 2-aminofluorene, and 0.56 +/- 0.12 mM and 0.74 +/- 0.09 nmol/min mg protein for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 2.40 +/- 0.32 mM and 10.62 +/- 0.04 nmol/min/mg protein for 2-aminofluorene, and 0.23 +/- 0.02 mM and 0.62 +/- 0.08 nmol/min/mg protein for p-aminobenzoic acid. For in vivo examination, the apparent Km and Vmax were 0.82 +/- 0.18 mM and 0.92 +/- 0.21 nmol/min/10 x 10(10) colony forming units (CFU) for 2-aminofluorene, and 0.78 +/- 0.14 mM and 0.52 +/- 0.06 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 0.50 +/- 0.08 mM and 0.62 +/- 0.22 nmol/min/ 10 x 10(10) (CFU) for 2-aminofluorene, and 0.52 +/- 0.21 mM and 0.26 +/- 0.04 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. This report is the first finding of emodin inhibition of arylamine N-acetyltransferase activity in a strain of H. pylori.

Evidence for arylamine N-acetyltransferase activity in the fungi Candida albicans

N-acetyltransferase activities were determined in Candida albicans, which is a member of the normal flora of the mucous membranes in the respiratory, gastrointestinal and female genital tract. The N-acetylation of 2-aminofluorene and p-aminobenzoic acid by the N-acetyltransferase from Candida albicans was determined using high pressure liquid chromatography. The activities (mean +/- S.D.) of N-acetyltransferase from Candida albicans cytosols were 1.06 +/- 0.01 nmol/min per mg protein for the acetylation of 2-aminofluorene substrate, and not detectable levels of acetyl-p-aminobenzoic acid for the acetylation of p-aminobenzoic acid. The apparent kinetic constants Km and Vmax values were 0.17 +/- 0.06 mM and 1.43 +/- 0.42 nmol/min per mg protein, respectively, for 2-aminofluorene substrate. The optimum pH value for the enzyme activity was 8.0. The optimal temperature for the enzyme activity is 40 degrees C for 2-aminofluorene substrate. Among a series of divalent cations and salts, Fe2+, SCN-, I-, and NH4+ were demonstrated to be the most potent inhibitors. The N-acetyltransferase activity was inhibited by iodoacetamide: at 0.25 mM iodoacetamide, activity was reduced 50% and 1.0 mM iodoacetamide inhibited activity more than 90%. This is the first demonstration of acetyl CoA arylamine N-acetyltransferase activity in the yeast-like fungus Candida albicans.

Evidence for arylamine N-acetyltransferase activity in the bacterium Helicobacter pylori

N-Acetyltransferase activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori from gastroduodenal disease patients. The N-acetyltransferase activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. The N-acetyltransferase activities from a number of Helicobacter pylori samples were found to be 0.91 +/- 0.12 nmole/min/mg protein for the acetylation of 2-aminofluorene and 0.75 +/- 0.22 nmole/min/mg protein for the acetylation of p-aminobenzoic acid. The apparent K(m) and V(max) values obtained were 1.10 +/- 0.08 mM and 2.34 +/- 0.14 nmol/min/mg protein for 2-aminofluorene, and 0.92 +/- 0.09 mM and 2.08 +/- 0.16 nmol/min/mg protein for p-aminobenzoic acid. The optimal pH value for the enzyme activity was 6.0 for both substrates tested. The optimal temperature for enzyme activity was 37 degrees C for both substrates. The N-acetyltransferase activity was inhibited by iodacetamide: at 0.25 mM iodacetamide, activity was reduced 50% and 1.0 mM iodacetamide inhibited activity more than 90%. Among a series of divalent cations and salts, Cu2+ and Zn2+ were demonstrated to be the most potent inhibitors. Among the protease inhibitors, only ethylenediaminetetraacetic acid significantly protected N-acetyltransferase. Iodoacetic acid, in contrast to the other agents, markedly inhibited N-acetyltransferase. This is the first demonstration of acetyl CoA:arylamine N-acetyltransferase activity in Helicobacter pylori.

A mutation causing pseudohypoaldosteronism type 1 identifies a conserved glycine that is involved in the gating of the epithelial sodium channel

Pseudohypoaldosteronism type 1 (PHA-1) is an inherited disease characterized by severe neonatal salt-wasting and caused by mutations in subunits of the amiloride-sensitive epithelial sodium channel (ENaC). A missense mutation (G37S) of the human ENaC beta subunit that causes loss of ENaC function and PHA-1 replaces a glycine that is conserved in the N-terminus of all members of the ENaC gene family. We now report an investigation of the mechanism of channel inactivation by this mutation. Homologous mutations, introduced into alpha, beta or gamma subunits, all significantly reduce macroscopic sodium channel currents recorded in Xenopus laevis oocytes. Quantitative determination of the number of channel molecules present at the cell surface showed no significant differences in surface expression of mutant compared with wild-type channels. Single channel conductances and ion selectivities of the mutant channels were identical to that of wild-type. These results suggest that the decrease in macroscopic Na currents is due to a decrease in channel open probability (P(o)), suggesting that mutations of a conserved glycine in the N-terminus of ENaC subunits change ENaC channel gating, which would explain the disease pathophysiology. Single channel recordings of channels containing the mutant alpha subunit (alphaG95S) directly demonstrate a striking reduction in P(o). We propose that this mutation favors a gating mode characterized by short-open and long-closed times. We suggest that determination of the gating mode of ENaC is a key regulator of channel activity.

The use of an extended spiral bladder flap for treatment of upper ureteral loss

PURPOSE

We demonstrated the effectiveness of an extended spiral bladder flap procedure for repair of upper ureteral injuries.

MATERIALS AND METHODS

Two patients with extensive ureteral loss underwent repair with a modified bladder flap based posterolaterally on the affected side, spiraled anteriorly and inferolaterally toward the contralateral bladder base, and then anastomosed directly to the renal pelvis.

RESULTS

With this technique renal function was preserved in both patients without obstruction on followup radiographs.

CONCLUSIONS

Using this extended bladder flap technique a well vascularized urothelial repair can be achieved for upper ureteral injury in select patients.

Factor structure of the Chinese version of the WAIS-R for Chinese adults in the lowest percentiles of IQ

The Chinese version of the WAIS-R was factor analyzed for a sample of 130 Chinese adults in Hong Kong who had low intellectual abilities. All subtests except the Vocabulary subtest were included for analyses. Results supported a three-factor solution composed of Verbal Comprehension, Perceptual Organization, and Memory/Freedom from Distractibility Factors, as well as a two-factor solution of classic Verbal-Perceptual dichotomy. Comparison of present two- and three-factor structure with individuals having low or normal IQ in Mainland China and North America revealed satisfactory congruence coefficients. However, our general factor accounted for only a small portion of common and total variance (28.5% and 35.3% respectively). Error variances of our subtests were large when compared to normative samples of Mainland China and US. Results were discussed in terms of clinical interpretation of the WAIS-R subtests, danger of using short-forms to assess IQ and need for normative studies of WAIS-R in Chinese-speaking countries.

Mutations in subunits of the epithelial sodium channel cause salt wasting with hyperkalaemic acidosis, pseudohypoaldosteronism type 1

Autosomal recessive pseudohypoaldosteronism type I is a rare life-threatening disease characterized by severe neonatal salt wasting, hyperkalaemia, metabolic acidosis, and unresponsiveness to mineralocorticoid hormones. Investigation of affected offspring of consanguineous union reveals mutations in either the alpha or beta subunits of the amiloride-sensitive epithelial sodium channel in five kindreds. These mutations are homozygous in affected subjects, co-segregate with the disease, and introduce frameshift, premature termination or missense mutations that result in loss of channel activity. These findings demonstrate the molecular basis and explain the pathophysiology of this disease.

Quantitative Measurement of Corneal Haze After Myopic PRK

OBJECTIVE

To design and evaluate an instrument for the objective measurement of haze in rabbits after myopic PRK.

METHODS

A circular fluorescent lamp bulb projected light onto the cornea through a circular collimating aperture covered with an orange filter. The image was collected on a centrally mounted CCD camera and the profile of the haze circle along its horizontal diameter determined.

RESULTS

Haze circles were observed and quantitated. In the first weeks, they were donut-shaped, frequently with a central bright area, but later they became square-topped. The instrument reproduced measurements with an error of a few percentage points and showed good long-term stability.

Thermoregulatory dysfunction in neuroleptic malignant syndrome

Hyperthermia is the central feature of neuroleptic malignant syndrome (NMS), but its etiology remains elusive. Two competing hypotheses implicate either hypothalamic dysfunction (inappropriate "set point") or direct myotoxicity (excessive peripheral heat production). These two models have distinct implications for thermoregulatory activity in NMS. The first predicts that the individual should respond as to a hypothermic threat or infection (the hypothalamus signals the body to raise its temperature). The second implies that an excessive heat load is perceived by the hypothalamus, which responds to this hyperthermic threat (it signals the body to lower its temperature). To assess the validity of these two hypotheses the thermoregulatory responses of a series of NMS patients (36 patients, 46 episodes) were examined using standard statistical methods. In contrast to normal mammalian thermoregulatory behavior, thermoeffector responses were not organized into either mode, but appeared to function somewhat independently and paradoxically. We conclude that neither hypothesis is sufficient to explain altered thermoregulation in NMS, and that the loss of integrated thermoeffector activity may be unique to this disorder.

Dopamine-induced inhibition of endogenous acetylcholine release from the isolated ileal synaptosomal preparations of guinea-pig mediated via alpha-adrenoceptors

1. The effect of exogenous dopamine on the release of endogenous acetylcholine (ACh) from isolated ileal synaptosomal guinea-pig preparations was examined by means of high pressure liquid chromatography with electrochemical detection. 2. Release of ACh was induced by substance P or by depolarization with high potassium (50 mM) in a medium containing atropine propranolol and naloxone. 3. Dopamine produced a concentration-dependent inhibition of the evoked ACh release induced by substance P or in samples depolarized by high potassium. This action of dopamine was not reversed by the dopamine receptor antagonists either for the DA2 subtype domperidone, or for the DA1 subtype, SCH23390. Fenoldopam, the agonist of dopamine DA1 receptors, or quinpirole, the agonist of dopamine DA2 receptors, reduced the evoked ACh release, although only in high, non-dopamine-specific concentrations. 4. Failure of guanethidine or desipramine to inhibit this effect of dopamine ruled out mediation by endogenous noradrenaline. 5. Idazoxan and yohimbine reversed this dopamine-induced inhibition at concentration sufficient to abolish the action of clonidine. Influx of (45)Ca stimulated by substance P or high potassium into synaptosomal preparations was attenuated in the presence of dopamine. This inhibition by dopamine was also reversed by idazoxan or yohimbine but not by dopamine receptor antagonists. Moreover, the dopamine-induced inhibitions of both the ACh release and the influx of (45)Ca disappeared in the samples treated with pertussis toxin at a dose sufficient to abolish the action of clonidine. 6. It is concluded that dopamine suppresses the influx of calcium ions into cholinergic nerve terminals via an activation of alpha2-adrenoceptors coupled with a pertussis toxin-sensitive GTP-binding protein, resulting in the decrease of ACh release from ileal synaptosomes of guinea-pigs.

Antihypertensive action of geraniin in rats

The effects of geraniin, one of the ellagitannins purified from the leaves of Sapium sebiferum, on blood pressure were investigated in the spontaneously hypertensive rat (SHR). A single intravenous bolus injection of geraniin into anaesthetized SHRs lowered the arterial mean blood pressure in a dose-dependent manner without affecting the heart rate. A similar action was also observed in the normotensive (WKY) rat that received this compound at a higher dose. Geraniin did not modify the baroflex sensitivity in the phenylephrine-challenged SHR. This tannin reduced the plasma noradrenaline in a dose-dependent fashion which was not influenced by adrenalectomy. Failure of the antagonists, idazoxan and yohimbine for alpha 2-adrenoceptors as well as haloperidol and domperidone for dopamine receptors, to reverse the antihypertensive actions of geraniin ruled out the possible mediation of these receptors. Moreover, geraniin attenuated the pressor responses to exogenous noradrenaline and Bay K 8644 to a similar degree, indicating the direct effect of this compound on vascular activity in rats. These results suggest that geraniin possesses the ability to lower systemic blood pressure through the reduction of noradrenaline release or by direct vasorelaxation.

Inhibitory effect of octopamine on the release of endogenous acetylcholine from isolated myenteric synaptosomes of guinea-pig

1. The effect of octopamine on the release of endogenous acetylcholine (ACh) from isolated ileal synaptosomal preparations of guinea-pigs was examined using high pressure liquid chromatography with electrochemical detection. Release of ACh was induced by substance P or by depolarization with high potassium (50 mmol/L) in medium containing atropine, propranolol and naloxone. 2. Octopamine produced a dose-dependent inhibition of substance P-induced ACh release. A similar inhibitory action of octopamine was found in the samples depolarized by high potassium as a reference. 3. The action of octopamine was not reversed by the dopamine receptor antagonists either for the DA-2 subtype, domperidone, or for the DA-1 subtype, SCH23390, or by haloperidol. However, idazoxan and yohimbine antagonized this octopamine-induced inhibition at concentrations sufficient to abolish the action of clonidine. 4. Failure of guanethidine or nomifensine to inhibit octopamine ruled out mediation by noradrenergic neurotransmitters. 5. Octopamine decreased the influx of [45Ca] stimulated by substance P into synaptosomal preparations and this was reversed by idazoxan or yohimbine at concentrations sufficient to block the action of clonidine. 6. Pertussis toxin abolished the inhibitory action of octopamine at a dose high enough to block the action of clonidine. 7. These results indicate that octopamine suppresses the influx of calcium ions into cholinergic nerve terminals of ileal synaptosomes of guinea-pigs via an activation of alpha 2-adrenoceptors coupled with a pertussis toxin-sensitive GTP-binding protein which results in a decrease of ACh release.

Characterization of two full-length cDNA sequences encoding for apoproteins of peridinin-chlorophyll a-protein (PCP) complexes

Characterizations are presented for RNA, 2 cDNA libraries, and 2 full-length cDNA sequences encoding for photosynthetic light-harvesting peridinin-chlorophyll a-protein (PCP) in the dinoflagellate Heterocapsa pygmaea. Subsequent analyses of the PCP system also indicate that (1) it is represented by multiple nuclear encoded genes, (2) a subset of mRNAs encoding for PCP apoproteins are regulated by growth irradiance, (3) PCP preproteins are larger than the mature apoproteins, and (4) PCP cDNA clones sequenced thus far contain a conserved region but are not identical. Results are discussed in the context of photoadaptation in dinoflagellates.

Inhibitory effect of xylamine on the uptake of [3H]dopamine into isolated striatal synaptosomes of the rats

The synaptosomal preparations from Wistar rat striata show a Na(+)-dependent, nomifensine-sensitive uptake of [3H]dopamine([3H]DA). Xylamine, a nitrogen mustard, attenuated this uptake of [3H]DA into the synaptosomes (IC50 = 0.2 microM). The dose-dependent reduction of [3H]DA uptake by xylamine indicated competitive kinetics. Action of xylamine was modified if the active transport inhibitor, ouabain or iodoacetate, was also incubated during the pretreatment period or if the content of Na+ in medium was changed. Also, xylamine displaced the binding of [3H]mazindol in a correlative way with the inhibition of [3H]DA uptake. However, the activity of Na+, K(+)-ATPase in synaptosomes was not modified by xylamine at concentrations sufficient to block the uptake of [3H]DA. These findings suggest that xylamine has the ability to compete with the transport of [3H]DA into striatal synaptosomes through an effect on the carrier instead of an action on enzymatic activity.

A comparison of diagnostic criteria for neuroleptic malignant syndrome

BACKGROUND

A variety of diagnostic criteria for neuroleptic malignant syndrome (NMS) have been used in clinical studies of this disorder, but it is not known if different criteria consistently identify NMS. This study examines agreement between three frequently used sets of diagnostic criteria in a series of possible NMS episodes.

METHOD

All clinically suspected NMS episodes occurring at a large tertiary psychiatric facility during a 6-year period were evaluated by three different sets of diagnostic criteria. Agreement among these criteria was quantified statistically by means of the kappa and intraclass correlation coefficients.

RESULTS

The NMS diagnostic criteria examined generally demonstrated only fair agreement with one another in the diagnosis of NMS. Agreement was best among these criteria when the "probable" category was employed. A complex interaction involving both definition and structure of individual diagnostic criteria and designation of criteria as major or minor appears to contribute to these findings.

CONCLUSION

The published diagnostic criteria used in this study do not consistently identify NMS episodes and demonstrate different thresholds for assigning this diagnosis. These differences are not due solely to different definitions of individual criteria (e.g., fever). Possible implications of these findings for clinical practice and research are discussed.

Diagnosis of venous leakage by 133Xe corporeal clearance after intracavernous injection of prostaglandin E1 in poorly responding patients

133Xe corporeal clearance after intracavernous (IC) prostaglandin E1 (PGE-1) injection was assessed in detecting venous leakage (VL) in a group of impotent patients with poor clinical response to PGE-1 injection. 133Xe corporeal washouts were done in the flaccid state and at full erection or at 20 min after the IC injection of 20 micrograms PGE-1 in cases where no full erection occurred in sequence on two separate days. In each case, data were acquired in frame mode after intracorporeal injection on one side of the midline just behind the glans of 0.1 ml, namely, 1-2 mCi (34-74 MBq) 133Xe in saline for 20 min. A time-activity curve was generated from the region of interest (ROI) at the site of injection and a computer routine was used to calculate clearance half-time (T1/2) in min and flow rate (Q) in ml per 100 g tissue per min. The data of 20 patients with equivocal response to IC PGE-1 were analysed. Of them, 14 had venous leakage and six had no vascular impairment (NVI). Venous leakage was proved by Doppler analysis, cavernosography after PGE-1, and/or selective arteriography. Twelve of 14 patients with VL had enhanced 133Xe corporeal clearance after PGE-1 with a significant decrease in T1/2 (mean +/- S.D.) from 115.9 +/- 196.0 to 13.3 +/- 13.4 (P less than 0.05) and increase in Q from 2.1 +/- 2.2 to 7.5 +/- 5.6 (P less than 0.01). In contrast, all six patients with NVI had decreased 133Xe corporeal clearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of calcium excretion in the stone-forming kidney in unilateral ureteral obstruction

Thirteen urolithiasis patients with unilateral obstructive uropathy were treated with percutaneous nephrostomy (PCN) either for urinary diversion, endopyelotomy, nephrolithtotmy or chemolysis. After percutaneous nephrostomy, the individual urine volume, creatinine clearance (Ccr), urinary absolute and fractional excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were measured separately in timed urine collections from a pigtail catheter and from the urethra. The data showed that Ccr and the absolute urinary excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were significantly lower in the PCN kidney immediately or 2 days after relief of obstruction. The ratio of total urinary calcium excretion to urinary creatinine excretion in the obstructed kidney was significantly greater than that in the contralateral kidney. The fractional excretions of calcium and magnesium increased as renal function decreased. The results showed that when the total Ccr is below normal, the apparent excretion of urinary calcium will be underestimated. However, when the total Ccr of patients is within normal range, hypercalciuria may be detected adequately and thus favors early implementation of an appropriate therapeutic strategy.

Maintenance lithium levels could be lowered: based on Taiwanese and Danish studies

Twenty-two patients, 8 males and 14 females, who had been lithium-free for at least 1 week were included in this study. All patients took 900 mg of Lithonate at 8:00 a.m. while in a fasting state. A 5 ml blood sample was taken at 9:00 a.m., 10 a.m., 12 noon, 3 p.m., 5 p.m., 11 p.m., and at 9 a.m. and 3 p.m. on the next day. Plasma was separated immediately, and the lithium level was measured by atomic absorption spectrophotometry. The pharmacokinetic parameters were as follows: K12 (microconstant) = 0.3455 +/- 0.5345 (mean +/- SD) h-1; K21 (microconstant) = 0.1691 +/- 0.1242 h-1; K10 (microconstant) = 0.1320 +/- 0.1112 h-1; Vl (volume of distribution of central compartment) = 16.9057 +/- 5.9384 1; Vss (volume of distribution at steady state) = 38.8917 +/- 11.4540 1; V-beta (volume of distribution of elimination phase) = 46.3809 +/- 13.8742 1; alpha (distribution rate constant) = 0.5932 +/- 0.7090; and beta (excretion rate constant) = 0.0361 +/- 0.0141. The mean elimination half-life, AUC (the area under the curve) and clearance were 22.5 +/- 9.9 h (range from 9.6 to 50.4 h), 16.33 +/- 5.52 mmoll-1h (8.69 to 31.81 mmoll-1 h), and 1.65 +/- 0.53 1h-1 (0.76 to 2.28 1h-1) or 28.59 +/- 9.58 ml/kg-1 h-1, respectively. There were no statistically significant differences in beta, AUC and clearance between Taiwanese/Chinese and Danish results. The possibility of lowering the traditional prophylactic therapeutic range of lithium to around 0.5-0.8 mmol/L is supported by the results of this study.

Radionuclide imaging clinical study. Corporeal 133Xe washout for detecting venous leakage in impotence

A quantitative test, corporeal 133Xe washout, was developed to detect venogenic impotence. Data were acquired in frame mode after intracorporeal injection of 0.1 ml (1-2 mCi or 37-74 MBq) of 133Xe in saline on one side of the midline just behind the glans in the flaccid state for 20 min. A time-activity curve (TAC) was generated from the region of interest (ROI) at the site of injection and a computer routine was then used to calculate clearance half-time (T1/2) in minutes and flow rate (Q) in ml/100 g tissue/min from corporeal 133Xe clearance. The data from 12 controls and 21 patients with venous leakage were analysed. In patients with venogenic impotence, T1/2 (mean +/- S.D.) was greatly increased (24.4 +/- 10.7 min vs 10.7 +/- 4.6 min in controls, P less than 0.005) whereas Q markedly decreased (2.4 +/- 1.3 ml/100 g tissue/min vs 5.4 +/- 2.3 ml/100 g tissue/min in controls, P less than 0.005). The sensitivity and specificity for detecting venous leakage at the optimal threshold of T1/2 equal to 13 min and Q equal to 3.7 ml/100 g tissue/min were 95 and 75%, respectively. The corporeal 133Xe clearance half-time and flow rate are two simple and clinically useful indices for detecting venous leakage.