Mandibular distraction osteogenesis for the management of upper airway obstruction in children with micrognathia: a systematic review.

Mandibular distraction osteogenesis (MDO) is increasingly used for neonates and infants with upper airway obstruction secondary to micrognathia. This systematic review was conducted to determine the effectiveness of MDO in the treatment of airway obstruction. The databases searched included PubMed, Embase, Scopus, and grey literature sources. The inclusion criteria were applied to identify studies in children with clinical evidence of micrognathia/Pierre Robin sequence (PRS) who had failed conservative treatments, including both syndromic and non-syndromic patients. Overall 66 studies were included in this review. Primary MDO for the relief of upper airway obstruction was found to be successful at preventing tracheostomy in 95% of cases. Syndromic patients were found to have a four times greater odds of failure compared to those with isolated PRS. The most common causes of failure were previously undiagnosed lower airway obstruction, central apnoea, undiagnosed neurological abnormalities, and the presence of additional cardiovascular co-morbidities. MDO was less effective (81% success rate) at facilitating decannulation of tracheostomy-dependent children (P<0.0001). Failure in these patients was most commonly due to severe preoperative gastro-oesophageal reflux disease, swallowing dysfunction, and tracheostomy-related complications. The failure rate was higher when MDO was performed at an age of ≥24 months. More studies are needed to evaluate the long-term implications of MDO on facial development and long-term complications.

Conditional tissue-specific expression of the acid alpha-glucosidase (GAA) gene in the GAA knockout mice: implications for therapy.

Both enzyme replacement and gene therapy of lysosomal storage disorders rely on the receptor-mediated uptake of lysosomal enzymes secreted by cells, and for each lysosomal disorder it is necessary to select the correct cell type for recombinant enzyme production or for targeting gene therapy. For example, for the therapy of Pompe disease, a severe metabolic myopathy and cardiomyopathy caused by deficiency of acid alpha-glucosidase (GAA), skeletal muscle seems an obvious choice as a depot organ for local therapy and for the delivery of the recombinant enzyme into the systemic circulation. Using knockout mice with this disease and transgenes containing cDNA for the human enzyme under muscle or liver specific promoters controlled by tetracycline, we have demonstrated that the liver provided enzyme far more efficiently. The achievement of therapeutic levels with skeletal muscle transduction required the entire muscle mass to produce high levels of enzyme of which little found its way to the plasma, whereas liver, comprising <5% of body weight, secreted 100-fold more enzyme, all of which was in the active 110 kDa precursor form. Furthermore, using tetracycline regulation, we somatically induced human GAA in the knockout mice, and demonstrated that the skeletal and cardiac muscle pathology was completely reversible if the treatment was begun early.

Determination of acid alpha-glucosidase activity in blood spots as a diagnostic test for Pompe disease.

BACKGROUND: Pompe disease is an autosomal recessive disorder of glycogen metabolism that is characterized by a deficiency of the lysosomal acid alpha-glucosidase. Enzyme replacement therapy for the infantile and juvenile forms of Pompe disease currently is undergoing clinical trials. Early diagnosis before the onset of irreversible pathology is thought to be critical for maximum efficacy of current and proposed therapies. In the absence of a family history, the presymptomatic detection of these disorders ideally can be achieved through a newborn-screening program. Currently, the clinical diagnosis of Pompe disease is confirmed by the virtual absence, in infantile onset, or a marked reduction, in juvenile and adult onset, of acid alpha-glucosidase activity in muscle biopsies and cultured fibroblasts. These assays are invasive and not suited to large-scale screening. METHODS: A sensitive immune-capture enzyme activity assay for the measurement of acid alpha-glucosidase protein was developed and used to determine the activity of this enzyme in dried-blood spots from newborn and adult controls, Pompe-affected individuals, and obligate heterozygotes. RESULTS: Pompe-affected individuals showed an almost total absence of acid alpha-glucosidase activity in blood spots. The assay showed a sensitivity and specificity of 100% for the identification of Pompe-affected individuals. CONCLUSIONS: The determination of acid alpha-glucosidase activity in dried-blood spots is a useful, noninvasive diagnostic assay for the identification of Pompe disease. With further validation, this procedure could be adapted for use with blood spots collected in newborn-screening programs.

Determination of acid alpha-glucosidase protein: evaluation as a screening marker for Pompe disease and other lysosomal storage disorders.

BACKGROUND: In recent years, there have been significant advances in the development of enzyme replacement and other therapies for lysosomal storage disorders (LSDs). Early diagnosis, before the onset of irreversible pathology, has been demonstrated to be critical for maximum efficacy of current and proposed therapies. In the absence of a family history, the presymptomatic detection of these disorders ideally can be achieved through a newborn screening program. One approach to the development of such a program is the identification of suitable screening markers. In this study, the acid alpha-glucosidase protein was evaluated as a marker protein for Pompe disease and potentially for other LSDs. METHODS: Two sensitive immunoquantification assays for the measurement of total (precursor and mature) and mature forms of acid alpha-glucosidase protein were used to determine the concentrations in plasma and dried blood spots from control and LSD-affected individuals. RESULTS: In the majority of LSDs, no significant increases above control values were observed. However, individuals with Pompe disease showed a marked decrease in acid alpha-glucosidase protein in both plasma and whole blood compared with unaffected controls. For plasma samples, this assay gave a sensitivity of 95% with a specificity of 100%. For blood spot samples, the sensitivity was 82% with a specificity of 100%. CONCLUSIONS: This study demonstrates that it is possible to screen for Pompe disease by screening the concentration of total acid alpha-glucosidase in plasma or dried blood spots.

Immunohistochemical localization of basic fibroblast growth factor in bovine ovarian follicles.

Basic fibroblast growth factor (bFGF, FGF2) controls cell proliferation and differentiation in many organs and tissues. In the ovary, cells proliferate and differentiate during folliculogenesis and during formation of the corpus luteum. While previous studies have inferred a role for bFGF in these processes, the precise contribution of bFGF to follicular activation or recruitment has not been established. For this reason, bFGF was immunolocalized in bovine follicles, using anti-bFGF immunoglobulin specific for the 1-24-amino acid terminus of the 18-kDa peptide. Basic FGF was immunolocalized to the cytoplasm of oocytes from bovine primordial and primary follicles. Strong immunostaining was also observed in corpora lutea, the ovarian surface epithelium, and smooth muscle cells surrounding blood vessels, while substantial levels of immunostaining were also present in cells of the theca interna. In most of the healthy antral follicles examined, the three or so layers of granulosa cells which were closest to the basement membrane were also stained, with greatest levels of staining at the most basal region of each cell. Atretic antral follicles had significant and uniform levels of immunostaining throughout the theca interna and the membrana granulosa. Immunostaining as described above was reduced to background levels when the primary specific immunoglobulin was preabsorbed with a 350 molar excess of peptide comprising the NH2-terminal 24 amino acids of bFGF. Based upon our previous observations and those reported here, we propose that basic fibroblast growth factor is synthesized by immature oocytes, especially those from primordial and primary follicles, and that bFGF has a potential role in activating follicle growth via stimulation of granulosa cell proliferation and follicular basement membrane synthesis.

Definition of a discontinuous immunodominant epitope at the NH2 terminus of the La/SS-B ribonucleoprotein autoantigen.

High-titer IgG autoantibodies to the La/SS-B ribonucleoprotein (RNP) are a hallmark of patients with primary Sjogren's syndrome. Anti-La/SS-B-positive human sera bind to multiple epitopes on recombinant La/SS-B, although the initial response is against an immunodominant epitope within the first 107 NH2-terminal amino acids (aa). Sequence analysis has identified a striking homology between aa 88-101 in this NH2-terminal region of La/SS-B and a feline retroviral gag polypeptide suggesting the anti-La/SS-B response may be initiated by cross-reactivity with an exogenous agent. In the present study, detailed mapping of this NH2-terminal epitope, using recombinant La/SS-B purified from the expression of overlapping DNA fragments spanning aa 1-107, has shown that this immunodominant epitope is a complex conformational or discontinuous epitope dependent upon both aa 12-28 and 82-99 for expression, even though these regions share no homology with each other. This requirement questions the significance of the homology between La/SS-B and a retroviral gag polypeptide in the generation of the B cell response to La/SS-B and is in accord with the general concept that B cells recognize conformational epitopes on antigens rather than small linear peptide sequences. The finding also reinforces the notion that native autoantigen could be the initiator of the autoimmune response.

An enhanced chemiluminescence detection system combined with a modified immunoblot technique for the detection of low molecular weight IgM in sera from healthy adults and neonates.

An enhanced chemiluminescence detection system combined with a modified immunoblot technique is described for the detection of low molecular weight IgM (LMW IgM) in human sera and cell culture supernatants at levels down to 2 pg/ml. This detection system is reliable, specific and more sensitive than the previously described chromogenic detection system. Importantly, this method has, for the first time, revealed LMW IgM in the sera from all 34 healthy adults and 26 neonatal cord bloods tested. A significant linear correlation was observed between the LMW IgM and the total circulating IgM in both the healthy adult sera (r = 0.88, p less than 0.001) and cord blood sera (r = 0.98, p less than 0.001).

Correlation of umbilical cord whole blood viscosity and the presence of fetal distress at birth: a mathematical modelling study.

This study was designed to investigate the relationship between umbilical cord blood viscosity and clinical parameters such as maternal parity, maternal smoking, mode of delivery, sex of infant and the incidence of fetal distress at birth using mathematical modelling. The results demonstrated vaginal delivery, male infants, infants of primigravidas and low cord whole blood viscosity at a high shear rate were covariables and were associated with an increased incidence of fetal distress and low Apgar scores.

Perifusion of human granulosa-luteal cells: response to LH stimulation.

LH pulse frequency and amplitude vary significantly during the menstrual cycle; however, it is not clear what significance the secretory pattern has for the ovary. We have developed an in-vitro perifusion system in which luteinized human granulosa cells (GC) can be exposed to various patterns of gonadotrophin stimulation. GC were recovered following follicle aspiration for in-vitro fertilization, grown on Cytodex-3 for 6 days, and then perifused with medium containing LH (or hCG), delivered with differing pulse frequencies and amplitudes. When pulses of LH were applied to the cells, progesterone secretion rose initially and then fell to the baseline as the LH concentration declined. Pulsatile administration of LH, over a period of 10 h, stimulated progesterone secretion more efficiently than did continuous LH. Finally, delivery to the cells of pulses of hCG, a ligand known to bind to the LH receptor but with binding characteristics distinct from those of LH, failed to elicit pulses of progesterone.

An analysis of the LH profile in relation to ovarian stimulation regimes and embryo transfer rates in an in vitro fertilisation programme.

A total of 128 patients undergoing 250 in vitro fertilisation (IVF) treatment cycles were studied to determine the relationship between ovarian stimulation regime, the status of the oestradiol levels in the 2 days prior to human chorionic gonadotrophin (hCG) administration and/or the onset of the luteinizing hormone (LH) surge, and the outcome of treatment cycles. The results demonstrated that hCG administration significantly improved the embryo transfer (ET) and pregnancy rates, although the mean interval between cessation of human menopausal gonadotrophin (hMG), and the onset of the LH surge also influenced the ET rate. hMG in conjunction with clomiphene citrate did not suppress the endogenous LH surge but enhanced the oestradiol levels in the 2 days prior to hCG administration and/or the onset of the LH surge. In stimulated cycles the diurnal rhythm of urinary LH surges was abolished. Finally, in certain patients, the LH pattern appeared to be repeated in sequential treatment cycles.

A rapid RIA for LH in serum and first morning void urine--application in an AID programme.

A rapid luteinizing hormone (LH) radioimmunoassay, with a 40-min incubation time, has been described and was used to measure the serum and urinary LH profiles in 92 menstrual cycles. A comparison of LH concentrations in first morning voiding (FMV) urine samples demonstrated that the pre-ovulatory LH peak in urine could be detected within 24 h of that in serum and that its offset was somewhat prolonged. FMV urine samples may be used as a convenient alternative to serum for the monitoring of artificial insemination by donor (AID) cycles.

Morphological characteristics and protein profile of isolated human decidual cells.

Isolated decidual cells were prepared from human decidual tissue obtained during early pregnancy by digesting the tissue fragments with 0.1% collagenase solution. Morphological studies of the cells were carried out using morphometric and flow cytometric analysis while the protein profile was analysed by polyacrylamide gel electrophoresis and gel filtration column chromatography. An average of 90% cell viability was achieved and the results showed that decidual cells constitute up to 70% of cell number and 89% of cell area of the isolated decidual cell suspension. The presence of serum proteins in uterine tissue extracts is due to blood contamination. However, the similarities of the non-serum protein profiles in tissue and cellular extracts validates previous studies performed in uterine fluids and tissue extracts. Finally, at least one unique uterine protein appeared to be a sub-unit of a larger molecule.

A comparative study of nucleic acid content and electrophoretic analysis of human decidual and endometrial proteins.

DNA, RNA and protein content expressed in terms of tissue wet weight was significantly reduced in decidua compared to endometrium. A protein with an approximate molecular weight of 36 000 was detected in higher incidence in decidua compared to normal endometrium. Another protein with a molecular weight of 26 000 was detected predominantly in decidua and secretory endometrium. Semiquantitative changes were also observed in the decidua. The peak area of one protein with a molecular weight of 48 000, which was significantly elevated in the secretory compared to the proliferative phase of the cycle, was significantly reduced in early pregnancy decidua. However, in term decidua the peak area of this protein was similar to those in endometrial tissue obtained in the luteal phase of the menstrual cycle. The results demonstrated that the transformation of endometrial stromal cells to decidua involves changes in nucleic acid and protein profiles and is accompanied by enhanced synthesis of at least one protein.

Electrophoretic analysis of human endometrial proteins.

An analysis of the protein composition of the human endometrium was undertaken using sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. The peak area of a protein with a molecular weight of 48,000 was significantly elevated in the secretory compared with the proliferative endometrium, while the peak area of another protein with a molecular weight of 41,000 was significantly reduced in the late proliferative and secretory endometrium compared with the early proliferative endometrium. A third protein with a molecular weight of 26,000 was detected predominantly in the secretory endometrium. The physiological implications of these findings are discussed.

Effects of contraceptive agents on the biochemical and protein composition of human endometrium.

An analysis of the nucleic acid and protein composition of endometrial tissue was undertaken in normal women and in patients using either steroidal oral contraceptives or intrauterine contraceptive devices (IUCD). In the presence of an IUCD, endometrial RNA/DNA and protein/DNA ratios were elevated in the secretory phase of the menstrual cycle compared to values obtained in normal women. In the oral contraceptive group, endometrial RNA/DNA and protein/DNA ratios were below the normal range in the late proliferative phase of the cycle. Typical electrophoretic profiles in the oral contraceptive group were similar to the control group, although a quantitative analysis revealed that the concentrations of certain characteristic uterine proteins were reduced. In the IUCD group, there was a preferential appearance of two proteins with approximate molecular weights of 36,000 and 26,000 daltons. Another protein with a molecular weight of 48,000 daltons, which demonstrated a cyclic change during the normal menstrual cycle, was reduced in both study groups. The results suggest that both agents studied induce changes in the macromolecular composition of the human endometrium which may relate to their contraceptive effect.

PIP: Nucleic acid and protein composition of endometrial tissue taken from normal women and patients using either oral contraceptives (OCs) or IUDs was analyzed in this comparative study. Endometrial ribonucleic acid (RNA)/deoxyribonucleic acid (DNA) and protein/DNA ratios were elevated in the presence of IUDs during the secretory phase of the menstrual cycle compared to values obtained in normal women. In OC users, endometrial RNA/DNA and protein/DNA ratios were below the normal range in the late proliferative cycle phase. Electrophoretic profiles of endometria were also performed. Typical electrophoretic profiles in the OC group were similar to controls, although a quantitative analysis revealed that the concentrations of certain characteristic uterine proteins were reduced in OC users. In contrast, there was a preferential appearance of 2 proteins in the IUD group; these proteins had approximate molecular weights of 36,000 and 26,000 daltons, respectively. A 48,000-dalton protein, which demonstrated a cyclic change during the normal menstrual cycle, was reduced in both IUD and OC users. Therefore, it is concluded that both types of contraception induce changes in the macromolecular composition of human endometrium, and that these changes may be related to their contraceptive modes of action.