Continuous infusion of local anaesthetic following laparoscopic hysterectomy--a randomised controlled trial.

OBJECTIVE: To estimate whether a continuous infusion of intraperitoneal local anaesthetic for 48 hours following laparoscopic hysterectomy reduced the need for opioids delivered with a patient-controlled analgesia pump. DESIGN: Double-blind randomised placebo-controlled trial. SETTING: District general hospital in the UK. POPULATION: Women undergoing a laparoscopic hysterectomy for a benign indication. METHODS: Women were randomised to receive either 0.5% levobupivicaine or 0.9% normal saline via an ON-Q elastomeric pump for 48 hours postoperatively. The amount of opioids used via the patient-controlled analgesia pump was recorded and pain was measured using an 11-point Box Scale. MAIN OUTCOME MEASURES: The primary outcome was the amount of patient-administered morphine used over the first 48 postoperative hours. Secondary outcomes were length of hospital stay, oral analgesia use and level of patient-reported pain. RESULTS: Sixty women participated and completed the trial. There was no difference (P = 0.59) in the median amount of patient-administered morphine used between the levobupivicaine (23 mg) and placebo (18.5 mg) groups; median group difference 3.0 (95% CI -7.0 to 14.0). There was also no difference in the length of hospital stay with 40% of the treatment group remaining in hospital >48 hours compared with 30% of the placebo group (P = 0.08). Pain scores at all postoperative time points remained similar, with a median group difference in pain scores of 1.0 (95% CI -1.0 to 2.0) at the end of the first postoperative day. CONCLUSIONS: Continuous infusion of 0.5% levobupivicaine into the peritoneal cavity following laparoscopic hysterectomy does not have any opioid-sparing effects.

Intensive Blood Pressure Management Preserves Functional Connectivity in Patients with Hypertension from the Systolic Blood Pressure Intervention Randomized Trial.

BACKGROUND AND PURPOSE: The Systolic Blood Pressure Intervention (SPRINT) randomized trial demonstrated that intensive blood pressure management resulted in slower progression of cerebral white matter hyperintensities, compared with standard therapy. We assessed longitudinal changes in brain functional connectivity to determine whether intensive treatment results in less decline in functional connectivity and how changes in brain functional connectivity relate to changes in brain structure. MATERIALS AND METHODS: Five hundred forty-eight participants completed longitudinal brain MR imaging, including resting-state fMRI, during a median follow-up of 3.84 years. Functional brain networks were identified using independent component analysis, and a mean connectivity score was calculated for each network. Longitudinal changes in mean connectivity score were compared between treatment groups using a 2-sample t test, followed by a voxelwise t test. In the full cohort, adjusted linear regression analysis was performed between changes in the mean connectivity score and changes in structural MR imaging metrics. RESULTS: Four hundred six participants had longitudinal imaging that passed quality control. The auditory-salience-language network demonstrated a significantly larger decline in the mean connectivity score in the standard treatment group relative to the intensive treatment group (P = .014), with regions of significant difference between treatment groups in the cingulate and right temporal/insular regions. There was no treatment group difference in other networks. Longitudinal changes in mean connectivity score of the default mode network but not the auditory-salience-language network demonstrated a significant correlation with longitudinal changes in white matter hyperintensities (P = .013). CONCLUSIONS: Intensive treatment was associated with preservation of functional connectivity of the auditory-salience-language network, while mean network connectivity in other networks was not significantly different between intensive and standard therapy. A longitudinal increase in the white matter hyperintensity burden is associated with a decline in mean connectivity of the default mode network.

In Vitro Wear of Glass-Ionomer Containing Restorative Materials.

STATEMENT OF PROBLEM: Advertisements of glass-ionomer-containing restorative materials recommend suitability as load-bearing permanent or semi-permanent restorations. Historically, unacceptably high wear rates limit clinical indications of glass-ionomer-containing restorations in this regard. OBJECTIVE: To compare the in vitro wear of contemporary glass-ionomer-containing dental materials commercially advertised for use in permanent dentition as load-bearing restorations in a chewing simulator. Resin composite was tested as a control. METHODS AND MATERIALS: A resin-modified glass ionomer (Ionolux, VOCO gmbH), a high viscosity glass-ionomer hybrid system (Equia Forte HT with Equia Coat, GC America), and a bioactive ionic resin with reactive glass filler (Activa Bioactive Restorative, Pulpdent) were evaluated. Filtek Supreme Ultra (3M ESPE) is a visible light-activated resin composite that served as a control. Standardized flat disk-shaped specimens (n=12/group) were submitted to 500,000 cycles with continuous thermal cycling against steatite antagonists. Volumetric wear was measured at 1000, 10,000, 200,000, and 500,000 cycles. RESULTS: There was a statistically significant difference in mean volumetric wear for Activa Bioactive Restorative (p=0.0081, 95% CI: 0.3973, 0.4982) and Equia Forte HT (p<0.001, 95% CI: 1.2495, 1.8493), but no statistically significant difference in mean volumetric wear for Ionolux (p=0.6653) compared to control. Activa Bioactive Restorative wore approximately 60% less than, and Equia Forte HT twice more than Filtek Supreme Ultra on average, respectively. CONCLUSIONS: Compared to a resin composite, contemporary glass-ionomer-containing restorative materials advertised for use as load-bearing restorations display measurably variable in vitro wear rates.

Science for the Next Century: Deep Phenotyping.

Our ability to unravel the mysteries of human health and disease have changed dramatically over the past 2 decades. Decoding health and disease has been facilitated by the recent availability of high-throughput genomics and multi-omics analyses and the companion tools of advanced informatics and computational science. Understanding of the human genome and its influence on phenotype continues to advance through genotyping large populations and using "light phenotyping" approaches in combination with smaller subsets of the population being evaluated using "deep phenotyping" approaches. Using our capability to integrate and jointly analyze genomic data with other multi-omic data, the knowledge of genotype-phenotype relationships and associated genetic pathways and functions is being advanced. Understanding genotype-phenotype relationships that discriminate human health from disease is speculated to facilitate predictive, precision health care and change modes of health care delivery. The American Association for Dental Research Fall Focused Symposium assembled experts to discuss how studies of genotype-phenotype relationships are illuminating the pathophysiology of craniofacial diseases and developmental biology. Although the breadth of the topic did not allow all areas of dental, oral, and craniofacial research to be addressed (e.g., cancer), the importance and power of integrating genomic, phenomic, and other -omic data are illustrated using a variety of examples. The 8 Fall Focused talks presented different methodological approaches for ascertaining study populations and evaluating population variance and phenotyping approaches. These advances are reviewed in this summary.

Metabolomics Insights in Early Childhood Caries.

Dental caries is characterized by a dysbiotic shift at the biofilm-tooth surface interface, yet comprehensive biochemical characterizations of the biofilm are scant. We used metabolomics to identify biochemical features of the supragingival biofilm associated with early childhood caries (ECC) prevalence and severity. The study's analytical sample comprised 289 children ages 3 to 5 (51% with ECC) who attended public preschools in North Carolina and were enrolled in a community-based cross-sectional study of early childhood oral health. Clinical examinations were conducted by calibrated examiners in community locations using International Caries Detection and Classification System (ICDAS) criteria. Supragingival plaque collected from the facial/buccal surfaces of all primary teeth in the upper-left quadrant was analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. Associations between individual metabolites and 18 clinical traits (based on different ECC definitions and sets of tooth surfaces) were quantified using Brownian distance correlations (dCor) and linear regression modeling of log2-transformed values, applying a false discovery rate multiple testing correction. A tree-based pipeline optimization tool (TPOT)-machine learning process was used to identify the best-fitting ECC classification metabolite model. There were 503 named metabolites identified, including microbial, host, and exogenous biochemicals. Most significant ECC-metabolite associations were positive (i.e., upregulations/enrichments). The localized ECC case definition (ICDAS ≥1 caries experience within the surfaces from which plaque was collected) had the strongest correlation with the metabolome (dCor P = 8 × 10-3). Sixteen metabolites were significantly associated with ECC after multiple testing correction, including fucose (P = 3.0 × 10-6) and N-acetylneuraminate (p = 6.8 × 10-6) with higher ECC prevalence, as well as catechin (P = 4.7 × 10-6) and epicatechin (P = 2.9 × 10-6) with lower. Catechin, epicatechin, imidazole propionate, fucose, 9,10-DiHOME, and N-acetylneuraminate were among the top 15 metabolites in terms of ECC classification importance in the automated TPOT model. These supragingival biofilm metabolite findings provide novel insights in ECC biology and can serve as the basis for the development of measures of disease activity or risk assessment.

In vivo impact of a 4 bp deletion mutation in the DLX3 gene on bone development.

Distal-less 3 (DLX3) gene mutations are etiologic for Tricho-Dento-Osseous syndrome. To investigate the in vivo impact of mutant DLX3 on bone development, we established transgenic (TG) mice expressing the c.571_574delGGGG DLX-3 gene mutation (MT-DLX3) driven by a mouse 2.3 Col1A1 promoter. Microcomputed tomographic analyses demonstrated markedly increased trabecular bone volume and bone mineral density in femora from TG mice. In ex vivo experiments, TG mice showed enhanced differentiation of bone marrow stromal cells to osteoblasts and increased expression levels of bone formation markers. However, TG mice did not show enhanced dynamic bone formation rates in in vivo fluorochrome double labeling experiments. Osteoclastic differentiation capacities of bone marrow monocytes were reduced in TG mice in the presence of osteoclastogenic factors and the numbers of TRAP(+) osteoclasts on distal metaphyseal trabecular bone surfaces were significantly decreased. TRACP 5b and CTX serum levels were significantly decreased in TG mice, while IFN-gamma levels were significantly increased. These data demonstrate that increased levels of IFN-gamma decrease osteoclast bone resorption activities, contributing to the enhanced trabecular bone volume and mineral density in these TG mice. These data suggest a novel role for this DLX-3 mutation in osteoclast differentiation and bone resorption.

Pax9's Interaction With the Ectodysplasin Signaling Pathway During the Patterning of Dentition.

In these studies, we explored for the first time the molecular relationship between the paired-domain-containing transcription factor, Pax9, and the ectodysplasin (Eda) signaling pathway during mouse incisor formation. Mice that were deficient in both Pax9 and Eda were generated, and the status of dentition analyzed in all progeny using gross evaluation and histomorphometric means. When compared to wildtype controls, Pax9+/-Eda-/- mice lack mandibular incisors. Interestingly, Fgf and Shh signaling are down-regulated while Bmp4 and Lef1 appear unaffected. These findings suggest that Pax9-dependent signaling involves the Eda pathway and that this genetic relationship is important for mandibular incisor development. Studies of records of humans affected by mutations in PAX9 lead to the congenital absence of posterior dentition but interestingly involve agenesis of mandibular central incisors. The latter phenotype is exhibited by individuals with EDA or EDAR mutations. Thus, it is likely that PAX9, in addition to playing a role in the formation of more complex dentition, is also involved with EDA signaling in the initiation of odontogenesis within the incisal domain.

Enamel defects and salivary methylmalonate in methylmalonic acidemia.

INTRODUCTION AND OBJECTIVE: To characterize enamel defects in patients with methylmalonic acidemia (MMA) and cobalamin (cbl) metabolic disorders and to examine salivary methylmalonate levels in MMA. SUBJECTS AND METHODS: Teeth from patients (n = 32) were evaluated for enamel defects and compared with age- and gender-matched controls (n = 55). Complementation class (mut, cblA, cblB and cblC) and serum methylmalonate levels were examined. Primary teeth from two patients were examined by light and scanning electron microscopy and salivary methylmalonate levels from two patients were analyzed. RESULTS: Enamel defects were significantly more prevalent per tooth in the affected group than the control group, across complementation types (P < 0.0001). The mut MMA subgroup had a significantly higher prevalence per individual of severe enamel defects than controls (P = 0.021), and those with enamel defects exhibited higher serum methylmalonate levels than those without (P = 0.017). Salivary methylmalonate levels were extremely elevated and were significantly higher than controls (P = 0.002). Primary teeth were free of enamel defects except for two cblC patients who exhibited severe enamel hypoplasia. One primary tooth from a cblC patient manifested markedly altered crystal microstructure. CONCLUSION: Enamel anomalies represent a phenotypic manifestation of MMA and cbl metabolic disorders. These findings suggest an association between enamel developmental pathology and disordered metabolism.

Endometriosis and its coexistence with irritable bowel syndrome and pelvic inflammatory disease: findings from a national case-control study--Part 2.

OBJECTIVE: To investigate whether the increased chances of having a diagnosis of irritable bowel syndrome (IBS) and pelvic inflammatory disease (PID) in women with endometriosis is due to misdiagnosis or co-morbidity. DESIGN: A case-control study of women aged 15-55 years with endometriosis and matched controls. SETTING: Data from the UK's General Practice Research Database for the years 1992-2001. SAMPLE: A total of 5540 women aged 15-55 years, diagnosed with endometriosis, each matched to four controls without endometriosis. The index date was defined as the date of diagnosis. METHODS: Data were analysed to determine whether women with endometriosis were more likely to receive a diagnosis of PIDor IBS than women without endometriosis. Odds ratios were calculated for endometriosis associated with IBS and PID before and after the index date. MAIN OUTCOME MEASURES: Diagnosis of IBS or PID before and after the index date. RESULTS: Compared with the controls, women with endometriosis were 3.5 times more likely to have received a diagnosis of IBS (OR 3.5 [95% CI: 3.1-3.9]). Even after women had been diagnosed with endometriosis, they were still two and a half times more likely to receive a new diagnosis of IBS when compared with the controls (OR 2.5 [95% CI: 2.2-2.8]). Similarly, women with endometriosis were more likely than those without endometriosis to have been treated for PID both before (OR 5.9 [95% CI: 5.1-6.9]) and after (OR 3.8 [95% CI: 3.1-4.6]) being diagnosed with endometriosis. CONCLUSIONS: Women with endometriosis are more likely to be diagnosed with IBS and PID than controls, even after a definitive diagnosis of endometriosis has been reached.

Can symptomatology help in the diagnosis of endometriosis? Findings from a national case-control study--Part 1.

OBJECTIVE: To determine the value of patient-reported symptoms in diagnosing endometriosis. DESIGN: A national case-control study. SETTING: Data from the UK General Practice Research Database for years 1992-2001. SAMPLE: A total of 5540 women aged 15-55 years, diagnosed with endometriosis, each matched to four controls without endometriosis. METHODS: Data were analysed to determine whether specific symptoms were highly indicative of endometriosis. Odds ratios for these symptoms were derived by conditional logistic regression analysis. MAIN OUTCOME MEASURES: Symptoms associated with endometriosis. RESULTS: The prevalence of diagnosed endometriosis was 1.5%. A greater proportion of women with endometriosis had abdominopelvic pain, dysmenorrhoea or menorrhagia (73%) compared with controls (20%). Compared with controls, women with endometriosis had increased risks of abdominopelvic pain (OR 5.2 [95% CI: 4.7-5.7]), dysmenorrhoea (OR 8.1 [95% CI: 7.2-9.3]), menorrhagia (OR 4.0 [95% CI: 3.5-4.5]), subfertility (OR 8.2 [95% CI: 6.9-9.9]), dyspareunia and/or postcoital bleeding (OR 6.8 [95% CI: 5.7-8.2]), and ovarian cysts (OR 7.3 [95% CI: 5.7-9.4]), and of being diagnosed with irritable bowel syndrome (IBS) (OR 1.6 [95% CI: 1.3-1.8]) or pelvic inflammatory disease (OR 3.0 [95% CI: 2.5-3.6]). Women with endometriosis were also found to consult the doctor more frequently than the controls and were twice as likely to have time off work. CONCLUSIONS: Specific symptoms and frequent medical consultation are associated with endometriosis and appear useful in the diagnosis. Endometriosis may coexist with or be misdiagnosed as pelvic inflammatory disease or IBS.

Maturational changes in dentin mineral properties.

In this study the changes in properties of the maturing mantle and circumpulpal dentin were quantitatively analyzed. Sections from six fetal bovine undecalcified incisors were used. Regions of mantle and circumpulpal dentin of sequential maturation stages were identified on spectroscopic images acquired by Fourier Transform Infrared Imaging. Spectroscopic parameters corresponding to mineral properties at these stages were analyzed and reported as a function of distance from the cervix of the incisor, the latter representing tissue age. Mineral parameters were correlated with distance from the cervix. Values of these parameters in mantle and circumpulpal dentin were compared. A multi-phasic pattern of changes was found for all the parameters examined, with most of the alterations occurring in the initial maturation period. The patterns of temporal variation in mantle and circumpulpal dentin mineral properties show distinct developmental stages and were not identical for the two dentin compartments. The study showed that mineral maturation in dentin is not a linear process and that mantle dentin is developmentally distinct from circumpulpal dentin, presenting at certain stages different physicochemical events during the maturation of the tissue.

Transgenic mice that express normal and mutated amelogenins.

Amelogenin proteins are secreted by ameloblasts within the enamel organ during tooth development. To better understand the function of the 180-amino-acid amelogenin (M180), and to test the hypothesis that a single proline-to-threonine (P70T) change would lead to an enamel defect similar to amelogenesis imperfecta (AI) in humans, we generated transgenic mice with expression of M180, or M180 with the proline-to-threonine (P70T) mutation, under control of the Amelx gene regulatory regions. M180 teeth had a relatively normal phenotype; however, P70T mineral was abnormally porous, with aprismatic regions similar to those in enamel of male amelogenesis imperfecta patients with an identical mutation. When Amelx null females were mated with P70T transgenic males, offspring developed structures similar to calcifying epithelial odontogenic tumors in humans. The phenotype argues for dominant-negative activity for the P70T amelogenin, and for the robust nature of the process of amelogenesis.

Demographic feedback between clonal growth and fragmentation in an invasive seaweed.

Many abundant plants, invertebrates, and seaweed are clonal, and this allows the formation of high-density aggregations, foraging, and the placement of modules into new space, and rapid rates of expansion. For these species, population density and rates of expansion are functions of recruitment of asexual modules and post-recruitment vegetative growth and survivorship. In this study, we provide the first experimental test of the relative importance of these two processes in determining the abundance of a clonal seaweed using Caulerpa taxifolia, an invasive green alga that spreads rapidly and reaches very high abundance. We asked two main questions: What is the relative importance to abundance (biomass) of vegetative stolon growth and fragment recruitment during expansion of established patches? Does greater fragment recruitment result in greater abundance in established patches? Vegetative growth of stolons underpinned patch expansion. Plots with stolons growing into them always had a greater abundance than plots where stolons were removed, even when fragment recruitment was increased. Greater recruitment only resulted in greater abundance when stolons were absent, a situation analogous to the establishment of new populations. Although post-recruitment processes were more important in determining abundance during patch expansion, there was greater ambient fragment recruitment when stolons were present compared to when they were absent, and as the abundance of C. taxifolia increased, demonstrating an important feedback between stolon growth, abundance, and fragment recruitment. In established patches, greater fragment recruitment over six months (six levels ranging from 0 to 480 recruits x m(-2) x mo(-1)) had no effect on biomass. Our experiments demonstrate that the rapid expansion and high abundance of invasive C. taxifolia are underpinned by post-recruitment vegetative growth and, during expansion, by a feedback between vegetative growth and asexual fragmentation.

Race and the decision to refer for coronary revascularization: the effect of physician awareness of patient ethnicity.

OBJECTIVES: We sought to assess whether there were differences, relative to racial ethnicity, in coronary revascularization recommendations made by a panel that had no knowledge of the patients' ethnicity. BACKGROUND: Coronary revascularization is employed less frequently in African American than in white patients. It is unclear whether this utilization pattern is driven by clinical differences between the two populations or by nonclinical factors. METHODS: Data were reviewed from 938 (26.5% African American, 73.5% white) consecutive cardiac catheterizations done between 1993 and 1995. Revascularization recommendations were made by cardiologists and cardiothoracic surgeons provided with the patients' clinical and angiographic data, but without knowledge of their ethnicity. Revascularization recommendations were compared between African American and white patients and correlated with clinical characteristics. RESULTS: No difference was noted in the percentage of African American and white patients recommended for revascularization, without reference to whether the recommendation was for percutaneous transluminal coronary angioplasty (PTCA) or for coronary artery bypass graft surgery (CABG) 40 vs. 46%, p = NS). African Americans were recommended more frequently for PTCA (22 vs. 18%, p = NS), whereas CABG was recommended for more white patients (28 vs. 18%, p = 0.002). Significantly fewer African Americans had disease in the left main or left anterior descending coronary artery or in multiple arteries. After adjusting for age, co-morbidity, left ventricular dysfunction and the extent of coronary disease, African Americans were more likely to have a recommendation for PTCA (odds ratio [OR] 1.42, 95% confidence interval [CI] 0.96 to 2.11, p = 0.08) and less likely to have a recommendation for CABG (OR 0.59, 95% CI 0.37 to 0.94, p = 0.02). CONCLUSIONS: This study suggests that when only clinical factors are considered, the rates of recommendations for revascularization will be similar for white and African American patients; but the type of revascularization procedure may differ by ethnicity and may depend, in part, on clinical factors.

Identification of cathepsin C mutations in ethnically diverse papillon-Lefèvre syndrome patients.

INTRODUCTION: Papillon-Lefèvre syndrome (PLS) is an autosomal recessive disorder characterised by palmoplantar keratoderma and severe, early onset periodontitis, which results from deficiency of cathepsin C activity secondary to mutations in the cathepsin C gene. To date, 13 different cathepsin C mutations have been reported in PLS patients, all of which are homozygous for a given mutation, reflecting consanguinity. AIM: To evaluate the generality of cathepsin C mutations in PLS, we studied an ethnically diverse group of 20 unrelated families. METHODS: Mutations were identified by direct automated sequencing of genomic DNA amplified for exonic regions and associated splice site junctions of the cathepsin C gene. Long range PCR was performed to determine the genomic structure of the cathepsin C gene. RESULTS: The cathepsin C gene spans over 46 kb, with six introns ranging in size from 1.6 to 22.4 kb. Eleven novel mutations and four previously reported mutations were identified in affected subjects from 14 families. Missense mutations were most common (9/15), followed by nonsense mutations (3/15), insertions (2/15), and deletions (1/15). Among these 14 probands, two were compound heterozygotes. Affected subjects with transgressions of the dermal lesions onto the knees or elbows or both had mutations in both the pro- and mature regions of the enzyme, although most were in the mature region. CONCLUSION: Mutations in the mature region of cathepsin C were more likely to be associated with the transgressions of the dermatological lesions, although the results were not statistically significant. A comprehensive list of all cathepsin C mutations described to date, representing 25 mutations from 32 families with PLS and related conditions, is also presented.

Comparison of gemfibrozil and lovastatin in patients with high low-density lipoprotein and low high-density lipoprotein cholesterol levels.

BACKGROUND: The efficacy of gemfibrozil and lovastatin in the treatment of patients who have an elevated low-density lipoprotein cholesterol (LDL-C) level and a low high-density lipoprotein cholesterol (HDL-C) level was compared. METHODS: After at least 6 weeks of a cholestgerol-lowering diet, 17 patients who had a mean baseline LDL-C level above 4.14 mmol/L (160 mg/dL) and an HDL-C level below 1.03 mmol/L (40 mg/dL) received gemfibrozil 600 mg twice daily and lovastatin 20 mg twice daily each for 6 weeks according to a randomized, crossover, double-blind research design. RESULTS: Lovastatin and gemfibrozil reduced LDL-C levels 34% and 9% and raised HDL-C levels 15% and 18%, respectively. CONCLUSIONS: Lovastatin is more effective in lowering LDL-C levels and is as effective as gemfibrozil in increasing HDL-C levels in these patients.

The molecular basis of hereditary enamel defects in humans.

The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel.

Intracytoplasmic retention of type VII collagen and dominant dystrophic epidermolysis bullosa: reversal of defect following cessation of or marked improvement in disease activity.

It has been recently shown that the presence of perinuclear "stellate bodies" within the epidermis in patients with a form of dominant dystrophic epidermolysis bullosa named "transient bullous dermolysis of the newborn" corresponds to collections of type VII collagen. To determine the temporal relationship of this unique immunohistochemical defect with course of clinical disease activity, we have longitudinally studied the expression of two epitopes of type VII collagen (LH 7:2; L3d) in nine patients in four such kindreds by immunofluorescence and immunoelectron microscopic technique. In every infant so studied at the time of active blistering, type VII collagen was detectable primarily within basilar and, to a lesser extent, suprabasilar keratinocytes. In contrast, type VII collagen was detectable solely in linear array along the dermoepidermal junction in skin from each patient following complete cessation or at least marked diminution of visible clinical disease activity. These findings support the hypothesis that the temporary mechanical fragility and blistering of the skin in infants with this rare subset of dominant dystrophic epidermolysis bullosa reflect the presence of reduced amounts of type VII collagen along the dermoepidermal junction, and that this diminution may be the result of either a delay in transport and integration of type VII collagen from basilar keratinocytes into the skin basement membrane or excessive phagocytosis of type VII collagen.

Regulation of insulin-like growth factor-I ribonucleic acid expression, polypeptide secretion, and binding protein activity by growth hormone in porcine preadipocyte cultures.

Insulin-like growth factor-I (IGF-I) is a mitogenic polypeptide postulated to mediate the effect of GH on adipose tissue development. To determine if the effect of GH could be mediated by the local production of IGF-I, we have characterized IGF-I RNA expression, polypeptide secretion, and binding protein activity in primary preadipocyte cultures derived from porcine adipose tissues. GH acutely regulated the abundance of multiple IGF-I RNA transcripts and resulted in a 2-fold increase in secreted immunoreactive IGF-I (iIGF-I) polypeptide in medium conditioned for 48 h by preadipocyte cultures relative to those not receiving GH. Immunocytochemical data indicated that IGF-I is synthesized by presumptive and mature adipocytes. The effect of GH on iIGF-I secretion was observed in cultures derived from both fetal and postnatal animals, while secreted IGF-binding protein activity was increased due to GH only in cultures from fetal animals. The increase in local IGF-I production in response to GH was associated with a decrease in adipocyte development, suggesting that local IGF-I may contribute to suppression of differentiated phenotype.