A dinucleotide mutation in the endothelin-B receptor gene is associated with lethal white foal syndrome (LWFS); a horse variant of Hirschsprung disease

Lethal white foal syndrome (LWFS) is a congenital anomaly of horses characterized by a white coat colour and aganglionosis of the bowel, which is similar to Hirschsprung disease (HSCR). We decided to investigate possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as recent studies in mutant rodents and some patients have demonstrated EDNRB defects. First, we identified a full-length cDNA for horse EDNRB . This cDNA fragment contained a 1329 bp open reading frame which encoded 443 amino acid residues. The predicted amino acid sequence was 89, 91 and 85% identical to human, bovine and mouse as well as rat EDNRB respectively, but only 55% identical to the human, bovine and rat endothelin A receptor (EDNRA). Secondly, sequence analysis, together with allele-specific PCR and the amplification- created restriction site (ACRS) technique, revealed a dinucleotide TC-- >AG mutation, which changed isoleucine to lysine in the predicted first transmembrane domain of the EDNRB protein. This was associated with LWFS when homozygous and with the overo phenotype when heterozygous.      

Relationship between HLA-DRB1 and DQ alleles and the genetic susceptibility to type 1 diabetes

Objective　To study the relationship between human leukocyte antigen (HLA)-DRB1 and DQ alleles and the genetic susceptibility of type 1 diabetes in North Chinese children. Methods　Polymerase chain reaction (PCR) techniques were used to amplify the second exon of DRB1 and DQ alleles, after which sequence specific olignucleotide probe (SSOP) dot blot hybridization techniques were used to analyze the amplified products. Results　DRB1*0301, DQA1*0301, DQB1*0201 alleles and DRB1*0301-DQA1*0501-DQB1*0201 haplotype were significantly increased in patients, while DQA1*0103 and DQB1*0601 alleles were significantly increased in controls. The distribution of DR4 and DR9 haplotypes in patients and controls were not significantly different, but DR3/DR4 and DR4/DR9 heterozygotes were significantly increased in patients. Conclusions　DRB1*0301, DQA1*0301 and DQB1*0201 confer susceptibility while DQA1*0103 and DQB1*0601 confer protection to type 1 diabetes. DRB1*0301-DQA1*0501-DQB1*0201 haplotype offers a predisposition to type 1 diabetes in North Chinese. Although the distribution of DR4 and DR9 in patients and controls had no significant difference, DR3/DR4 and DR3/DR9 heterozygotes were significantly increased in patients, showing that the susceptive effects of DR3 and DR4 or DR4 and DR9 haplotypes could be added up.     

Efficacy of "high-intensity" blue-light and "standard" daylight phototherapy for non-haemolytic hyperbilirubinaemia

We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy.     

Informed consent, parental awareness, and reasons for participating in a randomised controlled study

BACKGROUND: The informed consent procedure plays a central role in randomised controlled trials but has only been explored in a few studies on children. AIM: To assess the quality of the informed consent process in a paediatric setting. METHODS: A questionnaire was sent to parents who volunteered their child (230 children) for a randomised, double blind, placebo controlled trial of ibuprofen syrup to prevent recurrent febrile seizures. RESULTS: 181 (79%) parents responded. On average, 73% of parents were aware of the major study characteristics. A few had difficulty understanding the information provided. Major factors in parents granting approval were the contribution to clinical science (51%) and benefit to the child (32%). Sociodemographic status did not influence initial participation but west European origin of the father was associated with willingness to participate in future trials. 89% of participants felt positive about the informed consent procedure; however, 25% stated that they felt obliged to participate. Although their reasons for granting approval and their evaluation of the informed consent procedure did not differ, relatively more were hesitant about participating in future. Parents appreciated the investigator being on call 24 hours a day (38%) and the extra medical care and information provided (37%) as advantages of participation. Disadvantages were mainly the time consuming aspects and the work involved (23%). CONCLUSIONS: Parents' understanding of trial characteristics might be improved by designing less difficult informed consent forms and by the investigator giving extra attention and information to non-west European parents. Adequate measures should be taken to avoid parents feeling obliged to participate, rather than giving true informed consent.     

A monokine regulates colony-stimulating activity production by vascular endothelial cells

Human umbilical vein endothelial cells were cultured in supernatants of peripheral blood monocytes that had been cultured for 3 days with and without lactoferrin. Colony-stimulating activity (CSA) was measured in supernatants of the endothelial cell cultures and appropriate control cultures using normal, T-lymphocyte-depleted, phagocyte-depleted, low- density bone marrow cells in colony growth (CFU-GM) assays. Monocyte- conditioned medium contained a nondialyzable, heat labile factor that enhanced 4-15--fold the production of CSA by endothelial cells. The addition of lactoferrin to monocyte cultures reduced the activity of this monokine by 69%. Lactoferrin did not inhibit CSA production by monokine-stimulated endothelial cells. Therefore, vascular endothelial cells are potent sources of CSA, the production of CSA by these cells is regulated by a stimulatory monokine, and the production and/or release of the monokine is inhibited by lactoferrin, a neutrophil- derived putative feedback inhibitor of granulopoiesis. Inasmuch as a similar monokine is known to stimulate CSA production by fibroblasts and T lymphocytes, we suggest that mononuclear phagocytes play a pivotal role in the regulation of granulopoiesis by recruiting a variety of cell types to produce CSA.     

Bipotential effects of estrogen on growth hormone synthesis and storage in vitro

Increased pulses of serum GH coincide with rising estrogens during the reproductive cycle, suggesting estrogen regulation. However, there is lack of agreement about estrogen's direct effects on the pituitary. Pituitaries from cycling female rats were dispersed and plated for 24 h in defined media containing vehicle or 0.001-250 nm 17beta-estradiol. Estrogen (0.01-10 nm) increased the percentages of GH antigen-bearing cells in the anterior pituitary significantly (1.3- to 1.6-fold) and 0.01-1 nm concentrations also stimulated significant increases in GH mRNA-bearing cells and in the integrated OD for GH mRNA. However, 100-250 nm either had no effect or, inhibitory effects on the area of label for GH mRNA. To test estrogen's effects on expression of GHRH receptors, cultures were stimulated with biotinylated analogs of GHRH and target cells detected by affinity cytochemistry. Estrogen increased GHRH target cells in populations from rats in all stages of the cycle tested. Basal expression of GHRH target cells declined at metestrus. Cultures treated with 0-1 nm estrogen were then dual labeled for bio-GHRH followed by immunolabeling for GH with the antirabbit IgG-ImmPRESS peroxidase polymer. Over 98% of GH cells bound GHRH and 90-96% of GHRH-bound cells contained GH in all treatment groups. Thus, low concentrations of estrogen may stimulate expression of more cells with GH proteins, biotinylated GHRH binding sites, and GH mRNA, whereas high concentrations have no effect, or may reduce GH mRNA. These bipotential effects may help explain the different findings reported in the literature.     

Cytological factors that support nonparallel secretion of luteinizing hormone and follicle-stimulating hormone during the estrous cycle

Gonadotropes from cycling female rats were studied to investigate possible mechanisms for the nonparallel release of LH and FSH. The percentages of total gonadotropes increased from 14% during estrus (E) to 18% by diestrous day 2. More of these cells became multihormonal on the morning of proestrus (P; from 46% during diestrus to 69%). Since LH-containing cells increased from 7% at E to 13.3% during early proestrus, this suggests that monohormonal FSH cells may have contributed by synthesizing LH. Gonadotrope cell areas were greatest just before the LH surge (P 1600 h). Microdensitometric measurements demonstrated that the amount and density of immunoperoxidase stain for either gonadotropin subunit were highest during the midafternoon of P. Interestingly, the amount of stain for LH continued to increase during the LH surge, suggesting that the stain had detected newly synthesized LH beta. At the same time, the average density of the LH beta stain decreased. In contrast, the amount, concentration, and density of stain for FSH beta increased during the afternoon of P and decreased during late P and early E. The percentages of granules that contained immunogold stains for only LH or FSH (monohormonal granules) at P 1600-P 1700 h were 3-4 times higher than those in diestrous rats. The percentages of monohormonal LH granules declined during the proestrous surge, whereas percentages of monohormonal FSH granules declined during the first rise (P 1900 h) and after the second rise in serum FSH (E 0800 h). Finally, the average number of gold particles per micron 2 granule area rose over the value in diestrous rats during P 1600-P 1700 h. These studies suggest that multihormonal gonadotropes support nonparallel gonadotropin release by changing the rate of subunit packaging and transit in the Golgi complex.     

Castration induces time-dependent changes in the follicle-stimulating hormone beta-subunit messenger ribonucleic acid-containing gonadotrope cell population

We have previously observed 3- to 10-fold increases in pituitary LH beta-subunit mRNA levels in the rat 28 days after castration. These changes correlate with increases in percentages and areas of cells that bear the LH beta mRNA and with the amount of label for mRNA per cell. In contrast, FSH beta mRNA levels increase 2.5- to 4-fold 7-14 days after castration, decline to near-intact levels 28 days postcastration, and rise 4.5-fold by 96 days postcastration. The purpose of this study was to determine morphological correlates of these changes in FSH beta mRNA levels. Dispersed pituitary cells from intact and castrated rats were analyzed for FSH beta and LH beta mRNAs and protein by in situ hybridization techniques and immunocytochemistry, respectively. In intact animals over 79% of pituitary cells labeled for FSH beta mRNA were small (area less than 150 microns 2). However, 7 days after castration, the average area of labeled cells increased 4-fold (80% were over 200 microns 2 in area), without a significant change in percentages of FSH beta mRNA-containing cells. The amount of mRNA per cell (as measured by area of label per cell) increased 6-fold. Fourteen days after castration, the average area of cells containing FSH beta mRNA decreased to 2 times that in intact rats (48% were greater than 200 microns 2). The percentage of labeled cells increased from 11% (intact) to 20%. Furthermore, the dual labeling studies showed that 37% of these FSH cells were monohormonal (detected by FSH beta mRNA, but not LH beta antigen) compared with 23% in intact rats. At this same time, the FSH cells exhibited a decrease in the amount of mRNA per cell. In 21- to 84-day castrates, average areas of FSH beta mRNA remained at 2-2.5 times the areas of cells from intact rats. In addition, 21 days after surgery the percentages of labeled cells and amount of FSH beta mRNA per cell declined to those in intact rats. A greater proportion was multihormonal (only 15% expressed FSH beta mRNA but not LH beta antigens). At 84 days there were 2-fold increases in the percentages of labeled cells and the density of label, which correlate with the recovery in mRNA levels assayed at 96 days. Thus, factors that contribute to the early rise in FSH beta mRNA include increases in the amount of mRNA per cell, which coincides with increased cell area.(ABSTRACT TRUNCATED AT 400 WORDS)     

Conservative management of unilateral condylar hyperplasia

Objective

The purpose of this study was to eliminate orthodontic treatment in mild to moderate cases of condylar hyperplasia in its early stages by condylectomy.

Patients and methods

A total of five patients (two females and three males) aged between 17 and 40 years were treated with unilateral condylectomy of the involved side without orthodontic treatment. All patients underwent standardized clinical and radiological examination at initial consultation, before surgery, immediately after surgery, and follow-up. Objective and subjective evaluation of temporomandibular joint (TMJ) included maximal incisal opening, lateral excursions, correction of facial asymmetry, occlusal harmony, TMJ pain, and jaw function. Results were recorded at 5-year follow-up.

Results

In all our cases, we achieved good mouth opening and near to normal occlusion. Good facial aesthetics was obtained after 3 months postoperative follow-up without secondary orthodontic treatment.

Conclusion

Thus, we conclude that treatment of mild to moderate cases of unilateral condylar hyperplasia during the inactive phase can be treated with condylectomy without orthodontic treatment, and it significantly improves long-term surgical outcomes.