Postprandial apolipoprotein B100 and B48 metabolism in familial combined hyperlipidaemia before and after reduction of fasting plasma triglycerides*

Abstract Hepatic VLDL overproduction in familial combined hyperlipidaemia (FCH) may delay the clearance of atherogenic apolipoprotein (apo) B containing particles. We investigated if normalization of fasting plasma triglycerides (TG) by hypolipidaemic treatment results in improved metabolism of apo B48 and apo B100 in six male subjects with FCH and compared them to six normolipidaemic controls. The FCH patients were studied before (TG, 5·2±1·2 mmoll^-1; mean ± SEM) and after therapy (TG, 2·1±0·3 mmoll^-1) with either simvastatin (n= 4) or combined therapy with gemfibrozil (n= 2). The post-prandial changes of apo B100 and apo B48 were studied after a single oral fat meal (24h; 50 gram fatm^-2). Changes in triglyceride rich particles (TRP; d < 1·006 gml^-1) and remnant fractions (REM; d: 1·006–1·019g ml^-1) of apo B were quantitated by scanning silverstained SDS-PAGE (4–15%). Apo B48 in fasting TRP in untreated and treated FCH was 15% and 14% of total apo B, and 6% in controls (P < 0·05). In controls, postprandial B48 increased maximally at 4h by 81% in TRP and by 137% in REM compared to baseline. In treated FCH, the post-prandial apo B48 pattern normalized in TRP compared to the untreated state. Postprandial apo B100 in controls decreased in TRP and REM by 33% and 18% (P < 0·05). In untreated and treated FCH, postprandial apo B100 remained unchanged vs. baseline in TRP and in REM suggesting hypersecretion of VLDL. The elimination of B100—assessed as area under the curve—in TRP (32·5±3·6 au.h; mean±SEM) and REM fractions (33·2±3·1 au.h), improved significantly after treatment (21·0±2·8 and 20·4±3·3 au.h, respectively). The apo B48 clearance in TRP fractions was improved after treatment (4·3±1·4 au.h vs. 2·9±1·2 au.h; P= 0·06), but not in REM fractions (2·8±1·0 au.h vs. 1·8±0·5 au.h; NS). In conclusion, in FCH subjects with apo B100 hypersecretion and increased fasting plasma apo B48 levels, reduction of fasting plasma TG improved, but did not normalize, TRP apo B48 and B100 metabolism. However, therapy normalized postprandial apo B100 remnant metabolism. Impaired postprandial apo B metabolism may be instrumental in the development of premature atherosclerosis in FCH subjects.     

Transthoracic DC Shock May Represent a Serious Hazard in Pacemaker Dependent Patients

External defibrillation is widely used for the termination of various atrial and ventricular tachyarrhythmias, including pacemaker patients. Our study was intended to evaluate the effects of DC shocks in 36 patients with unipolar pacemakers implanted in the right pectoral region (25 DDD, 10 VVI, 3 AAI). The shocks were delivered with paddles on the anterior surface of the thorax, as far as possible away from the pacemaker. The pacing output was programmed at 0.5 msec and 5 V (25 patients), 4 V (1 patient), and 2.5 V (10 patients). Transient loss of capture occurred in 18 patients (50%). These patients, compared with those without capture failure, received higher peak and cumulative shock energies, respectively, 216 ± 99 versus 123 ± 50 joules (P < 0.002) and 352 ± 62 versus 147 ± 98 joules (P < 0.004) and had a lower pacemaker pulse amplitude (4.0 ± 1.2 vs 4.6 ± 1.0 V, P = 0.11). Failure to capture lasted from 5 seconds to 30 minutes (mean 157 sec). In 15 patients the ventricular stimulation threshold was measured before and serially after cardioversion. A six-fold threshold increase was observed 3 minutes after the shock (P < 0.004) with gradual recovery to nearly baseline values at 24 hours. Transient sensing failure occurred in 7 of the 17 patients in whom it could be evaluated (41%). Furthermore, three cases of shock induced pacemaker malfunctions were observed requiring replacement of the stimulator in two patients. In conclusion, the incidence of loss of capture in pacemaker patients subjected to electrical cardioversion/defibrillation is high. The phenomenon is due to an abrupt rise in stimulation threshold, caused by the electrical shock, and may represent a serious hazard in pacemaker dependent patients. The risk of pacing failure could be reduced by utilizing low shock energies when possible, and by programming the pacemaker at its maximal output before cardioversion.     

Prevalence of long face pattern in Brazilian individuals of different ethnic backgrounds

Objective:

The long face pattern is a facial deformity with increased anterior total facial height due to vertical excess of the lower facial third. Individuals with long face may present different degrees of severity in vertical excess, as well as malocclusions that are difficult to manage. The categorization of vertical excess is useful to determine the treatment prognosis. This survey assessed the distribution of ethnically different individuals with vertical excess according to three levels of severity and determined the prevalence of long face pattern.

Material and Methods:

The survey was comprised of 5,020 individuals of Brazilian ethnicity (2,480 females and 2,540 males) enrolled in middle schools in Bauru-SP, Brazil. The criterion for inclusion of individuals with vertically impaired facial relationships was based on lip incompetence, evaluated under natural light, in standing natural head position with the lips at rest. Once identified, the individuals were classified into three subtypes according to the severity: mild, moderate, and severe. Then the pooled sample was distributed according to ethnical background as White (Caucasoid), Black (African descent), Brown (mixed descent), Yellow (Asian descent) and Brazilian Indian (Brazilian native descent). The Chi-square (χ²⁾ test was used (p<0.05) to compare the frequency ratios of individuals with vertically impaired facial relationships in the total sample and among different ethnicities, according to the three levels of severity.

Results:

The severe subtype was rare, except in Black individuals (7.32%), who also presented the highest relative frequency (45.53%) of moderate subtype, followed by Brown individuals (43.40%). In the mild subtype, Yellow (68.08%) and White individuals (62.21%) showed similar and higher relative frequency values.

Conclusions:

Black individuals had greater prevalence of long face pattern, followed by Brown, White and Yellow individuals. The prevalence of long face pattern was 14.06% in which 13.39% and 0.68% belonged to moderate and severe subtypes, respectively.     

Synthesis and cytotoxicity evaluation of granular magnesium substituted β-tricalcium phosphate

Objective:

The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material.

Material and Methods:

The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE).

Results:

The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium.

Conclusion:

β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.     

A multidisciplinary treatment of congenitally missing maxillary lateral incisors: a 14-year follow-up case report

Absence of the maxillary lateral incisor creates an aesthetic problem which can be managed in various ways. The condition requires careful treatment planning and consideration of the options and outcomes following either space closure or prosthetic replacement. Recent developments in restorative dentistry have warranted a re-evaluation of the approach to this clinical situation. Factors relating both to the patient and the teeth, including the presentation of malocclusion and the effect on the occlusion must be considered. The objective of this study was to describe the etiology, prevalence and alternative treatment modalities for dental agenesis and to present a clinical case of agenesis of the maxillary lateral incisors treated by the closure of excessive spaces and canine re-anatomization. A clinical case is presented to illustrate the interdisciplinary approach between orthodontics and restorative dentistry for improved esthetic results. In this report, the treatment of a girl with a Class II malocclusion of molars and canines with missing maxillary lateral incisors and convex facial profile is shown. Treatment was successfully achieved and included the space closure of the areas corresponding to the missing upper lateral incisors, through movement of the canines and the posterior teeth to mesial by fixed appliances as well as the canines transformation in the maxillary lateral incisors. This is a 14-year follow-up case report involving orthodontics and restorative dentistry in which pretreatment, post-treatment, and long-term follow-up records for the patient are presented.