Hypoplasia of L5 and wedging and pseudospondylolisthesis in patients with spondylolysis: study with MR imaging

BACKGROUND AND PURPOSE

The association between L5 hypoplasia and bilateral spondylolysis was described earlier on conventional radiographs of the lumbar spine. The purpose of this study was to describe the findings on MR imaging in patients with hypoplasia of L5 and to correlate these findings with the presence of bilateral spondylolysis of L5.

MATERIAL AND METHODS

We studied the MR images of 22 patients with hypoplasia and posterior wedging of L5 and with bilateral spondylolysis at L5. The anteroposterior diameter of L4, L5, and S1 were measured and compared. The degree of posterior wedging of L5 was calculated. The degree of anterolisthesis was determined. The intervertebral disks of L4-L5 and L5-S1 were studied.

RESULTS

The mean difference between the anteroposterior diameter of L4 and L5 was 3.0 mm, or 8.8% shortening of L5 compared with L4. The mean difference between the anteroposterior diameter of L5 and S1 was 4.4 mm, or 12.3% shortening of L5 compared with S1. The mean percentage posterior wedging was 24.7%. In 13 patients, there was no anterior vertebral slipping. True anterolisthesis grade I was seen in 5 patients and anterolisthesis grade II in 4 patients. Diskarthrosis with disk dehydration of L4-L5 was seen in 20 of the 22 patients.

CONCLUSIONS

It is confirmed that hypoplasia of L5 can simulate anterolisthesis. Hypoplasia of the vertebral body of L5 can predict the presence of bilateral spondylolysis.

Orphanin FQ/nociceptin binds to functionally coupled ORL1 receptors on human immune cell lines and alters peripheral blood mononuclear cell proliferation

Orphanin FQ/nociceptin (OFQ/N) has been shown to modulate nociception, responses to stress and anxiety. We investigated OFQ/N function in human immune cells. We find that monocytic U937, T lymphocytic CEM, and MOLT-4 cell lines express OFQ/N binding sites at levels comparable to that of human SH-SY5Y neuroblastoma cells. We show that OFQ/N receptors are functionally coupled to G proteins in these cells. Finally OFQ/N decreases proliferation of phytohemagglutinin-stimulated peripheral blood mononuclear cells in vitro at doses ranging from 10(-13) to 10(-8) M. Thus, our data suggest that OFQ/N and OFQ/N receptor may act as an immunomodulatory system.

Abolition of morphine-immunosuppression in mice lacking the mu-opioid receptor gene

Opiates are potent analgesic and addictive compounds. They also act on immune responses, and morphine, the prototypic opiate, has been repeatedly described as an immunosuppressive drug. Pharmacological studies have suggested that the inhibitory action of opiates on immunity is mediated by multiple opioid receptor sites but molecular evidence has remained elusive. Recently, three genes encoding mu- (MOR), delta-, and kappa-opioid receptors have been cloned. To investigate whether the mu-opioid receptor is functionally implicated in morphine immunosuppression in vivo, we have examined immune responses of mice with a genetic disruption of the MOR gene. In the absence of drug, there was no difference between wild-type and mutant mice with regard to a large number of immunological endpoints, suggesting that the lack of MOR-encoded protein has little consequence on immune status. Chronic morphine administration induced lymphoid organ atrophy, diminished the ratio of CD4(+)CD8(+) cells in the thymus and strongly reduced natural killer activity in wild-type mice. None of these effects was observed in MOR-deficient mice after morphine treatment. This demonstrates that the MOR gene product represents a major molecular target for morphine action on the immune system. Because our previous studies of MOR-deficient mice have shown that this receptor protein is also responsible for morphine analgesia, reward, and physical dependence, the present results imply that MOR-targeted therapeutic drugs that are developed for the treatment of pain or opiate addiction may concomitantly influence immune responses.

Distribution of nociceptin/orphanin FQ receptor transcript in human central nervous system and immune cells

We have examined the distribution of the opioid receptor-like-1 (ORL-1) transcript in the human CNS as well as human immune cells by RT-PCR and RNAse protection. The hORL-1 mRNA was distributed throughout the brain and particularly abundant in cortical areas, striatum, thalamus and hypothalamus. In the immune system, gene transcription was observed in normal circulating lymphocytes and monocytes as well as in T, B and monocytic cell lines. A splice variant, lacking 15 nucleotides at the junction between exon 1 and exon 2, showed a distribution similar to the already known ORL-1 transcript. Altogether these results show comparable expression levels of the hORL-1 gene in both nervous and immune systems, suggesting that the ORL-1-encoded receptor may participate to neuronal and non-neuronal physiological functions in humans.

Detection of opioid receptor mRNA by RT-PCR reveals alternative splicing for the delta- and kappa-opioid receptors

The three mu-, delta- and kappa-opioid receptors have recently been cloned and characterized at the molecular level. Our analysis of opioid receptor transcripts by RT-PCR revealed two PCR products derived from delta and kappa mRNAs with size higher than expected from the known cDNA sequences. DNA sequencing showed additional nucleotides inserted between the known splice sites, indicating the possible existence of alternative splicing pathways for delta and kappa receptors. The novel delta-opioid receptor transcript is expressed in mouse brain and contains a 243 bp insertion. This additional sequence is located at the splice junction between the first and second coding exons and is encoded by a single exon located 9 kb upstream exon 2 in the mDOR gene. The other alternative transcript occurs in human monocytic and T lymphocytic cell lines and encodes a novel form of the kappa-opioid receptor. The PCR product presents a 23 bp deletion at the 3' end of exon 2 followed by a 246 bp insertion found between exons 2 and 3. In the hKOR gene, this insertion is encoded by two DNA segments. One of them is located 0.4 kb downstream exon 2 while the second is flanking exon 3 on the 5' side. Both novel putative delta and kappa exons present in-frame stop codons that would lead to truncated receptor proteins. A possible functional or regulatory role of these shorter proteins in opioid function remains to be determined.

Identification of kappa- and delta-opioid receptor transcripts in immune cells

To investigate the role of opioids as direct modulators of the immune response, we have searched for expression of the recently cloned delta, mu and kappa opioid receptors in immune cells. We have devised a reverse transcriptase-polymerase chain reaction strategy which specifically detects a region spanning putative transmembrane regions 2 to 7 for each transcript in both human and mouse immune cells. In human peripheral blood lymphocyte and monocyte preparations, delta was undetectable while the kappa transcript was present. The analysis of human cell lines revealed low but significant levels of delta opioid receptor transcripts in T, B or monocyte cell lines while the kappa transcript was found in B cell lines only. Investigation of murine cells showed the presence of transcript for the delta receptor in splenocytes and in some T and B cell lines. Unexpectedly, no expression of the mu receptor was detected. Sequence analysis of PCR products demonstrated nucleotide identity between immune and neuronal transcripts, indicating that they derive from the same genes. In conclusion, our results lead to the identification of kappa and delta opioid receptor transcripts in immune cells.

Temporal relationship and reliability of the clinical, hormonal, and ultrasonographic indices of ovulation in infertile women

To assess ovulatory function, 50 infertile but "normally" ovulating women were monitored closely during a single menstrual cycle with daily measurements of serum estradiol, progesterone, and LH (morning and evening urinary LH by standard radioimmunoassay and morning urinary LH by enzyme-linked immunosorbent assay); transvaginal ultrasound; basal body temperature (BBT) recording; and cervical mucus. All 50 cycles, 40 spontaneous and ten induced with clomiphene citrate, were ovulatory. Follicle rupture was confirmed by ultrasound in 47 cycles (94%), whereas three patients fulfilled the diagnostic criteria for luteinized unruptured follicle syndrome. Follicle rupture occurred on day +1 in three, on day +2 in 34, and on day +3 in ten of the ovulatory cycles. Urine LH testing correlated well with the serum LH peak, particularly in the evening urine, and predicted ovulation in all patients. The initial periovulatory rise in serum progesterone occurred on the same day as the LH surge (day 0) in 30%, on day +1 in 40%, on day +2 in 22%, and on day +3 or later in 8% of the cycles. The rise in BBT corresponded to an increase in serum progesterone to 5 ng/mL or greater. Neither the BBT nor cervical mucus was reliable in predicting ovulation.

Acute delta 9-tetrahydrocannabinol exposure: effects on hypothalamic-pituitary-testicular activity in mice

The endocrine functions of the median eminence, pituitary and testes were examined in male mice after exposure to delta 9-tetrahydrocannabinol (THC) either in vivo or in vitro. The secretion of luteinizing hormone-releasing hormone (LHRH) under basal conditions, and in the presence of norepinephrine (NE; 60 microM), was significantly enhanced in median eminence fragments obtained 1 hr post-treatment with THC (50 mg/kg), while addition of THC (250 ng/ml) to the incubation media enhanced clonidine, as well as NE-stimulated LHRH release, but did not affect basal LHRH release. In vitro exposure to THC also enhanced LHRH-stimulated LH release by pituitaries, but did not affect basal secretion rates. In vivo THC exposure tended to enhance pituitary responsiveness to LHRH, although this effect was not statistically significant. In testicular perifusions, addition of THC at a concentration of 250 ng/ml completely blocked hCG-stimulated T secretion within 30 min. The suppressive effects of a lower dose of THC, 25 ng/ml, required 60 min to inhibit T production, an effect which persisted for 60-80 min post-THC. These findings indicate that THC exposure enhances responsivity at neuroendocrine target sites, but attenuates gonadotropin-stimulated testicular steroidogenesis.