Expression cloning of cDNA encoding a seven-helix receptor from human placenta with affinity for opioid ligands

Here we report the expression cloning of cDNA encoding a putative opioid receptor from a human placenta cDNA library. Placental opioid receptors are of the kappa type. As the dynorphin opioid peptides are kappa-selective, a dynorphin ligand was used in an affinity-enrichment (panning) procedure to select transiently transfected COS-7 cells expressing kappa receptor binding sites. The cloned cDNA encodes a 440-residue protein of the seven-helix guanine nucleotide-binding protein (G-protein)-coupled receptor family. Ligand binding reveals a stereospecific site with typical opioid properties, which binds peptide and nonpeptide opioids with moderate affinity (Kd approximately 100 nM) and which lacks the expected kappa selectivity. The deduced transmembrane domain is 93% identical to the homologous region of the human neuromedin K (neurokinin B) receptor, but the N-terminal and C-terminal sequences have many dissimilarities. The expressed receptor binds opioid ligands but not tachykinins; and under the same conditions, a cloned rat neuromedin K receptor binds tachykinins but not opioids.

A follow-up study of heroin addicts five years after first admission to a methadone treatment program

A random sample (n = 260) of the first 799 admissions to the Santa Clara County Methadone Treatment Program was sought for interview five years after the date of their first dose; 80% were successfully located. Data from the year prior to entering methadone treatment were compared to data from the year prior to the follow-up interview. The two specific areas showing the most dramatic improvement were in heroin use and employment. During the year prior to the follow-up interview, 24% of the subjects with known outcome had no heroin use; 19% were abstinent from both heroin and methadone and at risk (not in jail or other treatment) for the entire year. Unemployment dropped from 51% to 19%. Subjects drank significantly more alcohol during the year prior to interview, with a 48% increase in the number of daily drinkers. Little or no change was seen in the use of other drugs, in the percentage of subjects with an arrest or jail time, or in the number living with an addicted person. Time in treatment was not a predictor of successful outcome and subjects who had left methadone treatment were doing at least as well as those continuously in methadone treatment.

Naltrexone treatment of heroin addiction: one-year follow-up

Pre-treatment characteristics and post-treatment outcome measures were compared for 40 patients who began naltrexone maintenance and 77 who did not after a 6-month period of temporary maintenance on L-alpha-acetylmethadol (methadyl acetate LAAM). Patients who chose to begin naltrexone were younger, had fewer incarcerations and fewer months incarcerated prior to LAAM treatment, had fewer opiate-free months following previous treatments, and were more likely to be of Caucasian ethnicity. One year later, significantly more patients who had received any naltrexone than those who had not were no longer in any treatment program and were opiate-free. We found no significant correlations between total duration of naltrexone-treatment and post-treatment outcome variables such as heroin use, arrests, incarcerations or enrollment in a treatment program.

The naloxone test for opiate dependence

Naloxone tests for opiate dependence were given to 296 applicants for treatment with the surrogate opiate levomethadyl acetate (LAAM, levo-alpha-acetylmethadol) and to 103 applicants for treatment with the opiate antagonist naltrexone. Thirty-five of the 296 LAAM applicants applied first for LAAM, then following detoxification, for naltrexone. There was a dramatic decrease in withdrawal signs and symptoms when the subject went from opiate-dependent to a nondependent state. From our experience, we devised a scoring guide and testing procedure based on objective signs. We propose a 2-step test, with an initial intramuscular dose, then (if necessary) an intravenous dose, to determine an applicant's eligibility for surrogate opiate or narcotic antagonist treatment.

Cognitive functioning under moderate and low dosage methadone maintenance

The Wechsler Adult Intelligence Scale (WAIS) was administered to two groups of patients in the Santa Clara County Methadone Maintenance Program who were receiving low and moderate daily stabilized dosages of methadone hydrochloride. In the two separate statistical analyses performed, there were no significant differences found between subtest scores or verbal, performance, and full-scale scores of the groups measured. These results, combined with observations regarding the similarities of WAIS profiles of the two groups, indicate that cognitive functioning as measured by the WAIS was not differentially affected by the two dosages.

A specific radioimmunoassay for the opioid peptide dynorphin B in neural tissues

Dynorphin-32 was recently isolated from porcine pituitary and shown to consist of dynorphin A (the originally isolated dynorphin heptadecapeptide) at the amino terminus, followed by Lys-Arg (a putative signal for proteolytic cleavage) and then a tridecapeptide, dynorphin B, at the carboxyl terminus. Dynorphin B, like dynorphin A, contains leucine enkephalin. The present report describes and validates a radioimmunoassay for dynorphin B using an antiserum, "13S", that does not crossreact with other known opioid peptides. Immunoreactive dynorphin B was estimated in rat and porcine neural tissues and found to be 2-3 fold higher than reported values for dynorphin A. Distribution based on tissue concentration was similar to that of dynorphin A, with very high concentrations in neurointermediate pituitary. Small quantities of antiserum "13S" are available to investigators upon request.

Behavioural treatment of orgasmic dysfunction: a controlled study

Twenty-two anorgasmic women received 20 sessions of a multiple-technique behavioural therapy. The design included blind ratings by two independent assessors, multiple assessment instruments, and a waiting list control group. Treatment was significantly better than no treatment in terms of: (1) the percentage of patients experiencing orgasm during at least 50 per cent of sexual relations; (2) the percentage of women reporting satisfactory sexual relations at least 50 per cent of the time; (3) patients' ratings of positive reactions to various sexual behaviours; and (4) assessors' global clinical ratings. Significant improvement was also noted on the MMPI, IPAT, and Symptom Check List. Improvement was maintained at a follow-up average 9 months later. These results support the impression that a behavioural approach offers much promise in treating female orgasmic dysfunction.

Activation of erythropoietin receptor in the absence of hormone by a peptide that binds to a domain different from the hormone binding site

Applying a homology search method previously described, we identified a sequence in the extracellular dimerization site of the erythropoietin receptor, distant from the hormone binding site. A peptide identical to that sequence was synthesized. Remarkably, it activated receptor signaling in the absence of erythropoietin. Neither the peptide nor the hormone altered the affinity of the other for the receptor; thus, the peptide does not bind to the hormone binding site. The combined activation of signal transduction by hormone and peptide was strongly synergistic. In mice, the peptide acted like the hormone, protecting against the decrease in hematocrit caused by carboplatin.

Further characterization of morphine-like peptides (endorphins) from pituitary

Pituitary peptides with opioid pharmacologic action (endorphins) can exist in several forms with different basicities and molecular weights from about 3000 to less than 1000 daltons. Partial purification yielded an endorphin at least 4 times more potent than normorphine and 16 times more potent than the endogenous brain pentapeptide methionine enkephalin. It is proposed that pituitary endorphin or a similar peptide in brain may be the precursor of brain enkephalin.

Levels of immunoreactive dynorphin in brain and pituitary of Brattleboro rats

The very potent opioid peptide, dynorphin, has recently been shown by radioimmunoassay and immunocytochemical techniques to be selectively concentrated in the pars nervosa of pituitary, suggesting a possible association of dynorphin with the neurohypophyseal hormones, vasopressin and oxytocin. In this study, we report that pituitary and brain contents of immunoreactive dynorphin in homozygote Brattleboro rats (unable to synthesize vasopressin) are similar to those in heterozygote animals and in normal Long-Evans rats. Thus, the syntheses of immunoreactive dynorphin and vasopressin in the hypothalamo-hypophyseal tract appear to be independently regulated.

Side effects of levomethadone and racemic methadone in a maintenance program

Sixty-six patients participated in a double-blind, crossover study comparing side effects, drug use, clinic attendance, and dose changes on levomethadone and d,l (racemic) methadone. The hypothesis under examination was that dextromethadone, while adding no narcotic actions to the racemate, was contributing to side effects. An earlier single-blind pilot study showed that 9 out of 11 side effects improved while patients were receiving levomethadone, but this larger study did not duplicate those results. Analysis of 25 variables showed no significant between levo- and racemic methadone. There appears to be no advantage in levomethadone over racemic methadone in the treatment of patients in maintenance programs.

A dynorphin-like opioid in the central nervous system of an amphibian

We have provided evidence for the existence of a biologically active opioid in toad (Bufo marinus) brain that is immunoreactive with antiserum raised against dynorphin (1-13). Compared with porcine dynorphin, this opioid is similar in apparent molecular weight on the basis of gel permeation chromatography and is more hydrophobic on the basis of high-performance liquid chromatography. After purification, its opioid biological activity was demonstrated on the guinea pig ileum myenteric plexus-longitudinal muscle preparation. It was found to be less potent, and to have a similar sensitivity to antagonism by naloxone, in comparison with porcine dynorphin. Because it is immunoreactive with antiserum specific for porcine dynorphin, it probably has considerable sequence homology. Generally, the tissue distribution of immunoreactive dynorphin in the toad is similar to that in the rat, with highest concentrations in the neurointermediate lobe of the pituitary. However, the anterior lobe of the toad pituitary contains considerably lower concentrations than are found in the rat anterior lobe. There appear to be three size classes of immunoreactive dynorphin in toad neural tissue, each with apparent molecular weight below 12,000, similar to the size classes of immunoreactive dynorphin found in pig and rat. However, in toad spinal cord (and possibly in brain) there is immunoreactive dynorphin of greater apparent molecular weight, which has not been reported in mammalian tissue. The contribution of each molecular size to the total immunoreactivity varies from tissue to tissue and is different from that observed in the rat.

Increased urinary nitrite excretion in children with minimal change nephrotic syndrome

OBJECTIVE

We tested the hypothesis that nitric oxide synthesis by the kidney is increased in children with primary nephrotic syndrome.

METHODS

We examined the urinary excretion of nitrite, a stable metabolite of nitric oxide, using the Griess reaction, in children with nephrotic syndrome.

RESULTS

In comparison with healthy children, patients with minimal change nephrotic syndrome had increased urinary nitrite excretion regardless of whether the disease was in relapse or remission (p < 0.025). In contrast, urinary nitrite excretion was similar in control subjects and patients with focal segmental glomerulosclerosis or IgA nephropathy.

CONCLUSION

These findings indicate that measurement of urinary nitrite excretion may be a useful test to help discriminate between minimal change nephrotic syndrome and focal segmental glomerulosclerosis in children with idiopathic nephrotic syndrome.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.