[Dissertations 25 years after date 46. Treatment of mandibular fractures]. / Proefschriften 25 jaar na dato 46. Behandeling van mandibulafracturen.

In the 1980s, professionals wanted to determine what the best method was for treating fractures of the mandibula. The emergence of osteosynthesis plates in the late 1960s, bringing with them the possibility of immediate functional restoration, had had a dramatic effect. This type of plate was most often placed by means of an extra-oral incision. A decade later, a system of smaller plates was introduced, which were placed intra-orally. A doctoral research project from 1991 investigated the advantages and disadvantages of the various methods of treating a mandibular fracture in order to determine which was most applicable. The importance of careful assessment on the basis of the type of fracture and the desired firmness of the osteosynthesis, described in the dissertation, is still decisive in conclusions concerning surgical treatment method and choice of material.

Lifestyle factors and metabolomic aging biomarkers: Meta-analysis of cross-sectional and longitudinal associations in three prospective cohorts.

Biological age uses biophysiological information to capture a person's age-related risk of adverse outcomes. MetaboAge and MetaboHealth are metabolomics-based biomarkers of biological age trained on chronological age and mortality risk, respectively. Lifestyle factors contribute to the extent chronological and biological age differ. The association of lifestyle factors with MetaboAge and MetaboHealth, potential sex differences in these associations, and MetaboAge's and MetaboHealth's sensitivity to lifestyle changes have not been studied yet. Linear regression analyses and mixed-effect models were used to examine the cross-sectional and longitudinal associations of scaled lifestyle factors with scaled MetaboAge and MetaboHealth in 24,332 middle-aged participants from the Doetinchem Cohort Study, Rotterdam Study, and UK Biobank. Random-effect meta-analyses were performed across cohorts. Repeated metabolomics measurements had a ten-year interval in the Doetinchem Cohort Study and a five-year interval in the UK Biobank. In the first study incorporating longitudinal information on MetaboAge and MetaboHealth, we demonstrate associations between current smoking, sleeping ≥8 hours/day, higher BMI, and larger waist circumference were associated with higher MetaboHealth, the latter two also with higher MetaboAge. Furthermore, adhering to the dietary and physical activity guidelines were inversely associated with MetaboHealth. Lastly, we observed sex differences in the associations between alcohol use and MetaboHealth.

Patterns of ethanol intake in male rats with partial dopamine transporter deficiency.

Mesolimbic dopamine signaling plays a major role in alcohol and substance use disorders as well as comorbidities such as anxiety and depression. Growing evidence suggests that alcohol drinking is modulated by the function of the dopamine transporter (DAT), which tightly regulates extracellular dopamine concentrations. Adult male rats on a Wistar Han background (DAT+/+) and rats with a partial DAT deletion (DAT+/-) were used in this study. First, using fast-scan cyclic voltammetry in brain slices containing the nucleus accumbens core from ethanol-naïve subjects, we measured greater evoked dopamine concentrations and slower dopamine reuptake in DAT+/- rats, consistent with increased dopamine signaling. Next, we measured ethanol drinking using the intermittent access two-bottle choice paradigm (20% v/v ethanol vs. water) across 5 weeks. DAT+/- rats voluntarily consumed less ethanol during its initial availability (the first 30 min), especially after longer periods of deprivation. In addition, DAT+/- males consumed less ethanol that was adulterated with the bitter tastant quinine. These findings suggest that partial DAT blockade and concomitant increase in brain dopamine levels has potential to reduce drinking and ameliorate alcohol use disorder (AUD).

Association between Dural AVFs and Cerebral Venous Thrombosis.

BACKGROUND AND PURPOSE: Recent reports suggest an association between dural AVFs and cerebral venous thrombosis. We aimed to investigate the specific temporal and anatomic association between the 2 conditions. MATERIALS AND METHODS: A consecutive cohort of adult patients with dural AVFs was seen at Amsterdam University Medical Centers (2007-2020). An experienced neuroradiologist re-evaluated the presence and imaging characteristics of dural AVFs and cerebral venous thrombosis on all available imaging. The temporal (previous/concurrent/subsequent) and anatomic (same/adjacent/unrelated venous sinus or vein) association between dural AVFs and cerebral venous thrombosis was determined. RESULTS: Among 178 patients with dural AVFs, the mean age was 58.3 (SD, 13.2) years and 85 (48%) were women. Of 55 patients (31%) with cerebral venous thrombosis, 34 (62%) were women. Four patients (7%) had cerebral venous thrombosis before the development of a dural AVF, 33 (60%) had cerebral venous thrombosis at the time of dural AVF diagnosis (concurrent), and 18 (33%) developed cerebral venous thrombosis during follow-up after conservative treatment. The incidence rate of cerebral venous thrombosis after a dural AVF was 79 per 1000 person-years (95% CI, 50-124). In 45 (82%) patients with dural AVFs and cerebral venous thrombosis, the thrombosis was located in the same venous sinus as the dural AVF, whereas in 8 (15%) patients, thrombosis occurred in a venous sinus adjacent to the dural AVF. CONCLUSIONS: One-third of patients with a dural AVF in this study were diagnosed with cerebral venous thrombosis. In almost two-thirds of patients, cerebral venous thrombosis was diagnosed prior to or concurrent with the dural AVF. In 97% of patients, there was an anatomic association between the dural AVF and cerebral venous thrombosis. These data support the hypothesis of a bidirectional association between the 2 diseases.

[The development consultation for children in whom the physician suspects a developmental disorder: early experiences in Maastricht]. / Het ontwikkelingsspreekuur voor kinderen bij wie de arts een ontwikkelingsstoornis vermoedt: eerste ervaringen in Maastricht.

The so-called development consultation of the Heuvelland health care organization in Maastricht was organized with a view to early detection of developmental disorders in young children (< or = 6 years), thereby minimizing dysfunctioning. Health centre physicians, general practitioners and school doctors can refer children aged 0-6 years to this combined consultation hour of a paediatrician, a children's neurologist, a children's physiotherapist and in some cases, an educationalist and a speech therapist. After the starting-up phase, the number of referred children was three to six per month. The referring physician is usually present at the joint consultation after the examinations. At this meeting it is attempted to arrive at a diagnosis or at least to draw up a treatment plan. After the meeting, the child's parents or guardians are informed of the team's findings. The first group of 60 children included 9 with a cerebral paresis and 18 with retarded motor development and speech retardation; 8 children were referred for exclusion of neurological/cerebral abnormalities.

[Guided bone regeneration for dental implantology]. / Geleide botregeneratie in de implantologie.

Guided bone regeneration nowadays offers good possibilities to repair local bone defects. Membranes are used to cover the defects. There are many types available. The anatomy of the defect determines mainly which membrane type should be used or which surgical steps should be followed. Most difficult are the one-wall defects, less difficult are four-wall defects. Guided bone regeneration is predictable, but the procedure is technical sensitive and complications and contaminations will easy occur. All steps need to be done carefully, including patient selection and postoperative follow-up care. Implant insertion into the defect can be done simultaneously but will give a higher risk for complications. For this reason, care should be taken for regeneration procedures in aesthetic demanding areas.

[Five-year evaluation of implants in the resorbed maxilla]. / Vijfjaarsoverleving van implantaten in de geresorbeerde bovenkaak.

The survival of implants placed in the resorbed maxillae was investigated. Both edentulous and partially edentulous patients were evaluated including those who underwent 'sinus lift' procedures. The group of patients with a sinus floor augmentation showed a five-year cumulative survival rate varying between 100% for fixed bridges on implants in the partially edentulous maxillae and 75.6% for implants under overdentures placed in severely resorbed edentulous maxillae. It is concluded that placement of implants in the augmented sinus-floor is justified, if the patient is well informed. The procedure can provide a good solution for the prosthetic problems of patients with a resorbed maxilla.

Functional buckling behavior of silicone rubber shells for biomedical use.

BACKGROUND: The use of soft elastic biomaterials in medical devices enables substantial function integration. The consequent increased simplification in design can improve reliability at a lower cost in comparison to traditional (hard) biomaterials. Functional bi-stable buckling is one of the many new mechanisms made possible by soft materials. The buckling behavior of shells, however, is typically described from a structural failure point of view: the collapse of arches or rupture of steam vessels, for example. There is little or no literature about the functional elastic buckling of small-sized silicone rubber shells, and it is unknown whether or not theory can predict their behavior. Is functional buckling possible within the scale, material and pressure normally associated with physiological applications? An automatic speech valve is used as an example application. METHOD OF APPROACH: Silicone rubber spherical shells (diameter 30mm) with hinged and double-hinged boundaries were subjected to air pressure loading. Twelve different geometrical configurations were tested for buckling and reverse buckling pressures. Data were compared with the theory. RESULTS: Buckling pressure increases linearly with shell thickness and shell height. Reverse buckling shows these same relations, with pressures always below normal buckling pressure. Secondary hinges change normal/reverse buckling pressure ratios and promote symmetrical buckling. All tested configurations buckled within or closely around physiological pressures. CONCLUSIONS: Functional bi-stable buckling of silicone rubber shells is possible with adjustable properties in the physiological pressure range. Results can be predicted using the proposed relations and equations.

Synchronous x-ray and radio mode switches: a rapid global transformation of the pulsar magnetosphere.

Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-"bright" mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-"quiet" mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.

Displaying chest X-ray by beamer or monitor: comparison of diagnostic accuracy for subtle abnormalities.

BACKGROUND: The advent of beamer projection of radiological images raises the issue of whether such projection compromises diagnostic accuracy. The purpose of this study was to evaluate whether beamer projection of chest X-rays is inferior to monitor display. METHODS: We selected 53 chest X-rays with subtle abnormalities and 15 normal X-rays. The images were independently judged by a senior radiologist and a senior pulmonologist with a state-of-art computer monitor. We used their unanimous or consensus judgment as the reference test. Subsequently, four observers (one senior pulmonologist, one senior radiologist and one resident from each speciality) judged these X-rays on a standard clinical computer monitor and with beamer projection. We compared the number of correct results for each method. RESULTS: Overall, the sensitivity and specificity did not differ between monitor and beamer projection. Separate analyses in senior and junior examiners suggested that senior examiners had a moderate loss of diagnostic accuracy (8% lower sensitivity, pp<0.05, and 6% lower specificity, p=ns) associated with the use of beamer projection, whereas juniors showed similar performance on both imaging modalities. CONCLUSION: These initial data suggest that beamer projection may be associated with a small loss of diagnostic accuracy in specific subgroups of physicians. This finding illustrates the need for more extensive studies.

Double-stranded strong-stop DNA and the second template switch in human immunodeficiency virus (HIV) DNA synthesis.

Synthesis of unintegrated retroviral DNA via reverse transcription is thought to involve two separate template switches. Minus-strand strong-stop DNA, a major product of in vitro reactions using detergent-treated virions, is synthesized prior to the first template switch. Plus-strand strong-stop DNA, which is found base-paired to near full-length minus-strand DNA in infected cells, is believed to be synthesized before the second template switch. Using a synchronized, one-step HIV infection model, we report here the detection in acutely infected cells of a novel double-stranded strong-stop HIV DNA with a discrete length of approximately 650 base pairs, commencing at or near the left hand end of the right-hand U3 region of the HIV long terminal repeat. The plus-strand of this double-stranded strong-stop DNA possesses the primer binding site sequence and appears to be synthesized prior to the completion of the synthesis of its complementary minus-strand. In contrast, the minus-strand of the double-stranded strong-stop DNA lacks the primer binding site sequence after RNaseH digestion. We propose that a transient free plus-strand strong-stop DNA is released from its template by displacement synthesis and subsequently used as template for the synthesis of its complementary minus-strand. The proposed transient free plus-strand strong-stop DNA may also mediate the second template switch.

De novo reverse transcription is a crucial event in cell-to-cell transmission of human immunodeficiency virus.

The proposal that replication of human immunodeficiency virus type 1 (HIV-1), mediated by cell-to-cell transmission of the virus, might bypass de novo reverse transcription was tested by using one-step cell-to-cell and cell-free virus infection systems. Two well characterized reverse transcriptase (RT) inhibitors, azidothymidine at 20 microM and phosphonoformic acid at 100 micrograms/ml, blocked HIV replication completely following both cell-free virus and cell-to-cell transmission infection, as determined from the kinetics of unintegrated viral DNA synthesis and supernatant RT production after virus infection. Our results confirm that de novo reverse transcription is a crucial and mandatory event in HIV-1 replication following cell-to-cell transmission of the virus.

Initiation of reverse transcription during cell-to-cell transmission of human immunodeficiency virus infection uses pre-existing reverse transcriptase.

H3B cells, a laboratory clone of H9 cells persistently infected with the HTLV-IIIB strain of human immunodeficiency virus (HIV), contained significant levels of cell-associated reverse transcriptase (RT) activity measured by in vitro assays using either exogenous or endogenous templates. The cell-associated RT activity detected using exogenous template was almost wholly in a soluble (non-sedimentable) form whereas endogenous activity sedimented as a particulate structure associated with viral RNA. Despite this, H3B cells did not contain episomal HIV DNA detectable by Southern blot, indicating that in vivo reverse transcription was not occurring to any significant extent in these cells. However, when susceptible HUT 78 cells were infected by co-cultivation with H3B cells, dramatic synthesis of episomal HIV DNA occurred. Concurrently with this de novo initiation of reverse transcription, however, we found no detectable change in intracellular levels or cleavage profiles of immunoprecipitable RT polypeptides. Finally, actinomycin D pre-treatment of H3B cells to prevent de novo transcription from donor cell proviral DNA after co-cultivation did not affect the initiation of in vivo reverse transcription following cell-to-cell HIV infection. These results demonstrated that cells persistently infected with HIV contained significant fully cleaved cell-associated RT in a form that was active in vitro but not in vivo and that following cell-to-cell transmission of HIV infection to susceptible cells, de novo reverse transcription was initiated without detectable evidence of further synthesis or proteolytic processing of HIV RT. The nature of this initiation process requires further study.