Messenger RNA editing of the human serotonin 5-HT2C receptor

RNA encoding the rat serotonin 5-HT2C receptor undergoes editing whereby one to four adenosines are converted to inosines. This conversion can change up to three codons out of a stretch of five in the second intracellular loop of the receptor. RNA editing of the rat 5-HT2C receptor that changes all three codons was shown previously to alter intracellular signaling by 5-HT without changing its receptor-binding affinity. We analyzed 5-HT2C receptor editing in human brain and hypothalamic RNA samples and confirmed that all four adenosine editing sites observed in rat were also present in human samples. Additionally, we identified a novel editing site in the middle edited codon that extends the repertoire of 5-HT2C receptors by six additional protein isoforms. We observed that editing reduces both the binding affinity and functional potency of agonists for recombinant human 5-HT2C receptor isoforms. This effect on binding affinity was proportional to the agonist's intrinsic activity, with full agonists most affected, and antagonists showing no effect. These data suggest that RNA editing may alter coupling energetics within the ternary complex, thereby altering agonist binding affinities, G protein coupling, and functional responses. RNA editing may thus provide a novel mechanism for regulating 5-HT synaptic signaling and plasticity.

Extensive junctional diversity in Ig light chain genes from early B cell progenitors of mu MT mice

Nontemplated (N) nucleotide additions contribute significantly to the junctional diversity of all Ag receptor chains in adult mice except Ig light (L) chains, primarily because terminal deoxynucleotidyl transferase (TdT) expression is turned off at the time of their rearrangement in pre-B cells. However, because some Ig L chain gene rearrangements are detectable earlier during B cell ontogeny when TdT expression is thought to be maximal, we have examined the junctional processing of kappa- and lambda-chain genes of CD45(B220)+CD43+ pro-B cells from mu MT mice. We found that both kappa and lambda coding junctions formed in these B cell precursors were extensively diversified with N-region additions. Together, these findings demonstrate that Ig L chain genes are equally accessible to TdT in pro-B cells as Ig heavy chain genes. Surprisingly, however, the two L chain isotypes differed in the pattern of N addition, which was more prevalent at the lambda-chain locus. We observed the same diversity pattern in pre-B cells from TdT-transgenic mice. These results suggest that some aspects of TdT processing could be influenced by factors intrinsic to the sequence of Ig genes and/or the process of V(D)J recombination itself.

Fibulin-2 exhibits high degree of variability, but no structural changes concordant with abdominal aortic aneurysms

We used conformation sensitive gel electrophoresis and direct sequencing of PCR products to screen for mutations in the cDNA for fibulin-2, an extracellular matrix protein, from 11 patients with abdominal aortic aneurysms and two controls. When compared with the published reference sequence, a total of 14 single-base sequence variations were detected. Seven of the changes were neutral in that they did not result in an amino acid substitution. There were five missense changes at sites not conserved between human and mouse, and two missense changes at sites conserved between human and mouse. All but two of the sequence variants studied were also present in an additional set of 102 control alleles analyzed. One of these two changes was a missense mutation, but it did not segregate with abdominal aortic aneurysms in the family, whilst the other change was neutral. In conclusion, fibulin-2 has a large number of sequence variations in comparison with our previous analyses of type III collagen, and these variations will be useful in association studies. There was an excellent overall agreement between direct sequencing of PCR-products and conformation sensitive gel electrophoresis.

Nursing the patient receiving continuous positive airway pressure therapy

The shortfalls of standard oxygen therapy and the increasing trend toward avoiding mechanical ventilation has led to greater use of Continuous Positive Airway Pressure (CPAP) therapy. What was once the domain of intensive care units has now become a common therapy in many acute clinical settings.

The effect of pamidronate on lumbar spine bone density and pain in osteoporosis secondary to systemic mastocytosis

Three patients with osteoporosis secondary to systemic mastocytosis are described. With the exception of the typical rash of urticaria pigmentosa, spinal pain caused by osteoporosis was the most prominent symptom. Intermittent single i.v. infusions of pamidronate have controlled pain an improved lumbar spine bone density.

Anti-implantation activity of antiestrogens and mifepristone

To develop a better postcoital contraceptive, the following antiestrogens were tested for their anti-implantation activity in the rat: anordrin, anordiol, tamoxifen, ICI 182,780, and RU 39411. The compounds were administered orally or subcutaneously (s.c.) to female rats on days 1, 2, and 3 of pregnancy. All the antiestrogens tested were 100% effective in preventing blastocyst implantation. The lowest effective doses when administered orally were 10, 1.25, 0.062, 6.0 (partially effective), and 0.01 mg/kg/day, respectively. The estimated median effective doses (ED50) were 5.60, 0.40, 0.035, 5.40, and 0.0074 mg/kg/day, respectively. When administered s.c., the minimum effective doses in preventing blastocyst implantation in all animals were 2.0, 0.1, 0.1, 0.1, and 0.01 mg/kg/day, respectively. Anordrin, anordiol, and ICI 182,780 were more potent when administered s.c.; whereas tamoxifen and RU 39411 were effective at similar doses when administered parenterally or orally. RU 39411 was the most potent among the antiestrogens tested and should be evaluated as a potential postcoital contraceptive. The administration of mifepristone, an antiprogestin, at a dose of 8 mg/kg/day blocked blastocyst implantation in all treated animals; whereas at a dose of 4 mg/kg/day or lower, the drug was ineffective. These findings confirm that estradiol and progesterone are essential for blastocyst implantation in the rat. The capacity of mifepristone to potentiate the anti-implantation activity of the antiestrogens was also determined. The combination of a non-effective dose of each of the antiestrogens (anordrin, anordiol, and tamoxifen), and RU 39411, with mifepristone at a non-effective dose, prevented pregnancy, demonstration that an antiprogestin and antiestrogen act synergistically in blocking blastocyst implantation in the rat. The antiestrogen compounds whose anti-implantation activities were potentiated by mifepristone were found to possess significant estrogenic activity, when assayed by measuring the increase in the uterine weights of ovariectomized rats. The only exception was ICI 182,780, which showed no estrogenic activity in the uterine weight bioassay and did not act synergistically with mifepristone in blocking blastocyst implantation. Estradiol was effective in preventing pregnancy at a dose of 1 microgram/kg/day. The combination of non-effective doses of estradiol and mifepristone did not prevent pregnancy. The findings that mifepristone potentiates the anti-implantation activity suggests that the synergistic effect may be a unique property of this class of antiestrogens.

Sialosyl-Tn antigen: initial report of a new marker of malignant progression in long-standing ulcerative colitis

BACKGROUND & AIMS

Expression of the mucin-associated carbohydrate antigen sialosyl-Tn (STn) correlates with malignant transformation in sporadic colonic neoplasms. The aim of this study was to analyze STn antigen expression in patients with long-standing ulcerative colitis (UC).

METHODS

STn antigen was assessed by immunohistochemistry in archival tissues. Study A was a retrospective chronological case-control study. Serial surveillance colonoscopic biopsy specimens without inflammation or dysplasia were analyzed in 7 patients who developed colon cancer and in 8 controls who did not develop colon cancer. Study B analyzed the anatomic distribution of STn expression in 17 cancer-bearing (case) and 6 cancer-free (control) colectomy specimens from patients with UC. In some colectomy specimens, STn was compared with aneuploidy, which was determined by flow cytometry.

RESULTS

In study A, among the 7 patients with UC who developed cancer, 6 patients (86%) expressed STn in at least one prior nondysplastic surveillance biopsy specimen from the same site. Only 3 of 8 control patients (38%) expressed STn. In study B, STn was expressed in 40 of 82 specimens (49%) from cancer-bearing colons but only 8 of 62 specimens (13%) from cancer-free colons. STn was expressed in most aneuploid areas but was also found in diploid, nondysplastic mucosa.

CONCLUSIONS

STn antigen seems to be a promising marker of cancer risk in patients with UC.

Clinical features of early onset, familial Alzheimer's disease linked to chromosome 14

Early onset familial Alzheimer's disease (AD) has an autosomal dominant mode of inheritance. Two genes are responsible for the majority of cases of this subtype of AD. Mutations in the beta-amyloid precursor protein (beta APP) gene on chromosome 21 have been shown to completely cosegregate with the disease. We and others have previously described the clinical features of families with beta APP mutations at the codon 717 locus in an attempt to define the phenotype associated with a valine to isoleucine (Val-->Ile) or a valine to glycine (Val-->Gly) change. More recently, a second locus for very early onset disease has been localized to chromosome 14. The results of linkage studies in some families suggesting linkage to both chromosomes have been explained by the suggestion of a second (centromeric) locus on chromosome 21. Here we report the clinical features and genetic analysis of a British pedigree (F74) with early onset AD in which neither the beta APP locus nor any other chromosome 21 locus segregates with the disease, but in which good evidence is seen for linkage on the long arm of chromosome 14. In particular we report marker data suggesting that the chromosome 14 disease locus is close to D14S43 and D14S77. Given the likelihood that F74 represents a chromosome 14 linked family, we describe the clinical features and make a limited clinical comparison with the beta APP717 Val-->Ile and beta APP717 Val-->Gly encoded families that have been previously described.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteopenia, neurological dysfunction, and the development of Charcot neuroarthropathy

OBJECTIVE

To determine factors that might be associated with the development of Charcot neuroarthropathy.

RESEARCH DESIGN AND METHODS

This cross-sectional prevalence study examined neurological function and bone density in matched groups of neuropathic diabetic patients with and without radiological evidence of Charcot neuroarthropathy.

RESULTS

Patients with Charcot neuroarthropathy had a global impairment of neurological function that was significantly greater than that of otherwise matched non-Charcot neuropathic patients. All 17 Charcot patients had evidence of autonomic neuropathy compared with 10 of the control subjects (P = 0.03). The Charcot patients had evidence of reduced bone density in the lower limbs compared with the neuropathic control subjects (P = 0.009), but relatively preserved bone density in the spine (P = 0.4 vs. control subjects).

CONCLUSIONS

We conclude that minor trauma in diabetic patients with peripheral neuropathy might result in a fracture in those with a reduced bone density and thus trigger the development of Charcot neuroarthropathy.

Differential effect of estrogen on the production of cyclin B1, cdc2 p34 and c-fos protein in rat uterus

The uterine content of c-fos protein, cyclin B1 (cell cycle protein) and cdc2 p34(cyclin-dependent kinase) in immature and mature rats was determined using the enhanced chemiluminescence(ECL) western blot method. Cyclin B1 was found predominantly in immature rat uterus and cdc2 p34 only in mature rat uterus. Several isoforms of c-fos oncogene protein were present in both mature and immature rat uteri. An additional immunoreactive c-fos protein with an estimated molecular weight of 28 kDa was found in mature rat uterus and was missing in immature uterus. Uteri from ovariectomized rats treated with estrogen and/or ICI 182,780, an antiestrogen, were analyzed by ECL western blot. cdc2 p34 and the c-fos 28 kDa protein were found in estradiol-treated rat uteri and were not detected in uteri of control and ICI 182,780-treated animals; whereas Cyclin B1 was absent in uteri from control and estradiol-treated ovariectomized animals. ICI 182,780 administered to estradiol-treated ovariectomized rats blocked the induction of cdc2 p34 and the c-fos 28 kDa protein in the uterus. The present results show that the production of the cell cycle factors, cyclin B1, cdc2 p34 and c-fos, during rat uterine growth are under different regulatory controls. cdc2 p34 and c-fos 28 kDa protein are under the control of estradiol; whereas cyclin B1 and the majority of the immunoreactive isoforms of c-fos are not influenced by this hormone.

A two-year clinical study of the effects of two triphasic oral contraceptives on plasma lipids

OBJECTIVE

Oral contraceptive formulations can alter plasma lipid and lipoprotein levels; however, lower-dose triphasic tablets show only minimal metabolic effects during 6 or 12 cycles of use. Involvement of lipids in chronic cardiovascular conditions, plus long-term use of oral contraceptive tablets, prompted this first 24-cycle study of the effect of triphasic formulations on young women.

METHODS

69 women assigned randomly to an ethinyl estradiol/levonorgestrel formulation (Triphasil) or an ethinyl estradiol/norethindrone formulation (Ortho 7/7/7) and 25 control women (no hormonal contraception) had blood sampled for lipids and lipoproteins pre-trial, and at 3- or 6-cycle intervals for 24 cycles.

RESULTS

At cycle 24, control women experienced no significant change from baseline in any variable except apolipoprotein B (apo B). Plasma apo B increased 42% (P < .01), reflecting the LDL apo B increase (42%, P < .01). Both combination formulations significantly increased apo B (plasma, VLDL, IDL and LDL); the increases ranged between 47% and 84%. Plasma apo A1 rose (15%, P < .001) in the Ortho 7/7/7 group only. Plasma and LDL triglycerides were increased significantly (P < .001) by the norethindrone product, 43% and 81%, respectively, and plasma and LDL cholesterol, 14% and 28%, respectively. Cholesterol decreased in all other subfractions, including HDL (11%, P < .01). HDL cholesterol decreased significantly in the Triphasil group (8%, P < .05); no other cholesterol subfractions changed significantly. All cycle-24 lipid and lipoprotein values remained well within respective normal ranges.

CONCLUSION

Although 2-year exposure to the triphasic oral contraceptive formulations changed the lipid risk factors for cardiovascular disease only within normal ranges, there remains potential for long-term health effects when compounded with other risk factors.

Synthesis and secretion of an estrus stage-specific protein by rat uterus

A specific protein with an estimated molecular weight of 260 kDa was found to be synthesized and secreted into the incubation medium by rat uterus only during the estrus stage of the cycle. This secreted uterine protein was designated as estrus stage-specific protein (ESP). ESP was not produced by pregnant, lactating or immature pup rat uteri. Estradiol administered to ovariectomized rats induced production of ESP which was blocked by the antiestrogen, ICI 182, 780. The present results show that the synthesis and secretion of ESP is regulated by estradiol and this protein maybe involved in blastocyst implantation.

Understanding patterns of immunoglobulin gene rearrangements

When immunoglobulin (Ig) gene rearrangements are analyzed, several patterns emerge. The rearrangements at the various loci generally appear in a specific temporal order. In addition, within a given locus the frequency of rearrangement of the various gene segments is not equal but is skewed towards preferential rearrangement of particular gene segments. Understanding the reasons for these patterns will shed light on the mechanism of recombination, the regulation of rearrangement, and the relationship between Ig gene rearrangement and B cell development. In this review, we discuss evidence that the observed patterns of Ig gene rearrangement are due to a combination of factors including the recombination signal sequences, sequences in the coding termini, the accessibility of genetic elements to V(D)J recombinase, and cellular selection.

Contrasting effects of Mycoplasma fermentans and M. felis on the viability and chemiluminescence response of human polymorphonuclear leukocytes

Trypan blue exclusion was used to estimate the viability of human polymorphonuclear leukocytes (PMNL) in the presence of Mycoplasma felis and two strains of M. fermentans (PG18 and incognitus). The competence of PMNL to mount a respiratory burst when challenged with the mycoplasmas was also monitored by luminol-dependent chemiluminescence (CL). Both un-opsonised and non-immune human serum opsonised M. felis cells had little effect on PMNL viability. In contrast, PMNL viability was reduced markedly by un-opsonised cells of M. fermentans strain incognitus and, to a lesser extent, strain PG18, and opsonisation of these mycoplasmas further enhanced killing. Death of PMNL in the presence of M. fermentans was not associated with the autonomous production of active oxygen species during the respiratory burst as M. felis induced a high CL response from PMNL, whereas that induced by M. fermentans strain incognitus was significantly lower. M. fermentans may invade mammalian cells and it is suggested that the mechanism of PMNL death could be related to the ability of M. fermentans to penetrate host cell membranes.

Urinary clusterin in chronic nephrotoxicity in the rat

The excretion of clusterin was compared with that of N-acetyl-beta-glucosaminidase (NAG) in rats given gentamicin daily for 2 months to determine whether clusterin excretion stays elevated after NAG excretion falls during chronic gentamicin administration. Clusterin was measured by radioimmunoassay and NAG by the hydrolysis of 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide. Gentamicin at 110 mg/kg was given daily for 44 days and thereafter, at 90 mg/kg daily. The excretion rate of both proteins rose rapidly, peaked, and then declined; however, the clusterin values stayed significantly above control values for the entire study, whereas NAG values were close to normal during the last 10 days, even though tubulointerstitial disease was active at that time. For this reason, the further evaluation of clusterin as a marker of renal tubular cell injury or death is warranted.

Migraine madness: recurrent psychosis after migraine

A 69 year old man with longstanding migraine with aura had four episodes of psychosis lasting 7-28 days during a 17 year period. During attacks he had formed visual hallucination and delusions, including reduplicative paramnesia. His mother was similarly affected. His EEG showed symmetrical frontal delta waves. The time course and EEG changes are similar to acute confusional migraine. The reduplicative paramnesia suggests a focal non-dominant hemisphere dysfunction.

A randomized comparative open study of the effects of two oral contraceptives, Triphasil and Ortho 7/7/7, on lipid metabolism

This study assessed serum lipid, lipoprotein and apolipoprotein changes during one year in 3 groups of nonsmoking women: 1) Triphasil(R); 2) Ortho(R) 7/7/7; 3) Controls. Both oral contraceptives contain the estrogen, ethinyl estradiol(EE), in combination with a progestin in three different ratios during each cycle. The progestin in Triphasil is d-norgestrel, as the dl-racemate norgestrel (NG), whereas that in Ortho 7/7/7 is norethindrone(NE). Total plasma triglycerides were elevated significantly from baseline (p < 0.001) with Ortho 7/7/7 at 3, 6 and 12 months, but only at 3 months with Triphasil, p = 0.047. Triglycerides were elevated in the LDL fraction with Ortho 7/7/7 at 3 months (p = 0.001), 6 months (p = 0.018) and 12 months (p = 0.010). In contrast, LDL triglycerides were not significantly elevated with Triphasil. Similarly, IDL triglycerides were elevated only in the Ortho 7/7/7 group at 6 months (p = 0.002) and 12 months (p = 0.001). Plasma cholesterol was elevated only in the Ortho 7/7/7 group at 3, 6 and 12 months with p values of 0.009, 0.005 and 0.010, respectively. Cholesterol in the LDL fraction was elevated with Ortho 7/7/7 at 12 months (p = 0.002). Plasma apolipoprotein B (apo B) increased at least 24% from baseline for both the Triphasil and Ortho 7/7/7 groups at 3 and 12 months (p < 0.001). However, at 6 months, apolipoprotein B increased only 17.7% (p = 0.008) with Triphasil compared to 29.7% (p < 0.001) with Ortho 7/7/7 at 6 months. Apo B was increased (p < 0.001) in LDL with Triphasil at 3 months only, whereas LDL apo B was increased at 3, 6 and 12 months with Ortho 7/7/7 (p < 0.001, p = 0.020 and p = 0.012, respectively). Apo B increased dramatically in the IDL fraction of both oral contraceptive user populations, with the range of increases being between 48% and 87% during the year (p < 0.001 at all times). Significant elevations in VLDL apo B ranged from 71% to 106% (p < 0.001) with Triphasil and from 42.4% (p < 0.005) to 72.6% (p < 0.001) with Ortho 7/7/7. In conclusion, norethindrone- and dl-norgestrel-formulations have divergent effects on several components of plasma lipoprotein and lipid metabolism, but both products increase plasma and IDL apo B.

Worth vs Polarized four-dot test

A direct comparison between the Worth four-dot (W4D) and Polarized four-dot (P4D) flashlights is reported in a randomized trial on 107 unselected patients greater than 2.5 years old. The primary outcome variable was the interpretable response rate. Secondary outcomes were response time and age of test failure. There were 29 patients who failed to complete the W4D test, but only 10 patients who could not complete the P4D test, giving interpretable response rates of 73% and 91%, respectively (p < .001). The P4D test was found to be less dissociative and easier to administer. It also had a higher detection rate for fusion. We recommend its use as a tool in the clinical evaluation of binocular sensorial states.

Antihypertensive and hemodynamic effects of calcium channel blockade with isradipine after acute exercise

In a randomized, double-blind, placebo-controlled, crossover study with two 4-week treatment periods, we investigated the effects of calcium channel blockade with 5 mg slow release oral isradipine on postexercise blood pressure and systemic hemodynamics (echocardiography) in ten hypertensive patients. The results show that the combination of exercise and isradipine treatment exerts additive antihypertensive effects in hypertensive patients after exercise. The antihypertensive effect of prior exercise with placebo was related to a significant fall in total peripheral resistance. After exercise during isradipine treatment, total peripheral resistance was lower than with placebo. Thus, isradipine exerts an additional antihypertensive effect during the postexercise period, which appears to be mediated by a further reduction of total peripheral resistance.