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SamenvattingDe coronacrisis kan beschouwd worden als een ‘natuurlijk experiment’ waarin de sociale context aanzienlijk is veranderd. Het is nog grotendeels onbekend hoe jongeren daarop reageren en welke gedragingen veranderen. We hebben een cohortvergelijking gemaakt van derdeklassers (N = 177, Mleeftijd = 15,00) van de middelbare school vóór de coronacrisis (voorjaar 2019) met een qua demografische kenmerken vergelijkbare groep derdeklassers (N = 188, Mleeftijd = 14,95) tijdens de eerste lockdown (voorjaar 2020). We vergeleken de domeinen eetgedrag, leefstijl en sociaal-emotionele gezondheid tussen beide cohorten en keken naar de samenhang binnen en tussen domeinen voor beide cohorten. De consumptie van zoete snacks thuis, alcoholgebruik en eenzaamheid waren in het coronacohort hoger dan vóór de coronacrisis (niet significant na correctie). De consumptie van fruit thuis, van suikerhoudende dranken en ongezonde snacks buitenshuis, en matige en zware fysieke activiteit kwamen minder voor tijdens de lockdown. Relatietevredenheid met ouders, geluksgevoel en stress door school waren lager vergeleken met het cohort vóór de lockdown. Roken, stress thuis en relatietevredenheid met beste vriend(in) waren in beide cohorten even hoog. Het patroon van samenhang binnen en tussen de domeinen verschilde. Verder onderzoek moet uitwijzen hoe veerkrachtig jongeren op de langere termijn zijn en welke jongeren ondersteuning nodig hebben om terug te veren.

The corona crisis can be considered a 'natural experiment', in which the social context has changed dramatically. It is largely unknown how adolescents respond to this, and which behaviors change. We have compared a cohort of ninth graders (

Background: Patients with clinically diagnosed dysplastic nevi or a family history of melanoma with or without histologically diagnosed dysplastic nevi seem to be at higher risk for the development of multiple melanomas. Objective: Our purpose was to determine which factors increased the risk for the development of subsequent melanomas. Methods: This was a retrospective study in 56 patients with 157 melanomas. Results: Early age at onset (58.9%), clinically diagnosed dysplastic nevi (82.0%), a histologically diagnosed dysplastic nevus (64%), family history of clinically diagnosed dysplastic nevi (70.8%) or melanoma (64.7%) and a histologically diagnosed dysplastic nevus in combination with a family history of melanoma (48%) were found in a high percentage of patients. The mean age at diagnosis was 38.2 years. The mean interval between the first and second melanoma was 34.3 months. Of the second melanomas, 76.8% developed in a different anatomic region from the first melanomas. The mean tumor thickness (Breslow) decreased from 1.11 mm for the first melanomas to 0.90 mm for the second melanomas. Conclusion: The results suggest that genetic factors might be involved in a certain subset of patients in whom melanomas develop early and successively. (J Am Acad Dermatol 2001;44:22-7.)

We characterized beta 1 integrin subunit expression on three different cultures of benign human nevomelanocytes (NMC) and on four different cell cultures of human dysplastic nevus (DN) cells by flow cytometry analysis and examined their role in mediating cell spreading and migration on collagen type IV (CN IV) and laminin (LN) coated substrates by using a quantitative video image analysis system. The seven human NMC and DNC cultures expressed heterogeneous levels of beta 1, alpha 2, alpha 3 and alpha 6 integrin subunits. Image analysis showed that a significant increase (P < 0.001) in cell spreading and migration of the DN cells was induced on increasing coating concentrations of CN IV and LN. However, the NMC did not show an increase in cell spreading or migration on these substrates when compared to the substrates coated with denatured BSA only. The CN IV-induced cell spreading of the DN cells was significantly inhibited by anti-beta 1 mAb (AIIB2), anti-alpha 2 mAb (P1E6), or anti-alpha 3 mAb (P1B5), but not by mAb against alpha 6 integrin subunit (GoH3). The DN cell spreading on LN was not significantly inhibited by these mAbs. In contrast, the migration of the DN on CN IV and LN was significantly inhibited by anti-beta 1 mAb, anti-alpha 2 mAb, anti-alpha 3 mAb and anti-alpha 6 mAb. These data suggest that the alpha 2 and alpha 3 subunit are important for cell spreading of the DN on CN IV, although they are less important in cell spreading on the extracellular matrix component LN.(ABSTRACT TRUNCATED AT 250 WORDS)

To the Editor: African tickbite fever (ATBF), which is caused by Rickettsia africae, is well documented in travelers to southern Africa (1–3) and transmitted by ungulate ticks of the genus Amblyomma. Positive serologic results were reported in 9% of patients (1) and 11% of travelers (4) from southern Africa. We report an outbreak of ATBF with an attack rate of 100% among 12 Dutch travelers to Swaziland.

Summary Metastatic disease is the primary cause of death in breast cancer, the most common malignancy in Western women. Loss of E-cadherin is associated with tumor metastasis, as well as with invasive lobular carcinoma (ILC), which accounts for 10%– 15% of all breast cancers. To study the role of E-cadherin in breast oncogenesis, we have introduced conditional E-cadherin mutations into a mouse tumor model based on epithelium-specific knockout of p53. Combined loss of E-cadherin and p53 resulted in accelerated development of invasive and metastatic mammary carcinomas, which show strong resemblance to human ILC. Moreover, loss of E-cadherin induced anoikis resistance and facilitated angiogenesis, thus promoting metastatic disease. Our results suggest that loss of E-cadherin contributes to both mammary tumor initiation and metastasis.

Five families with the dysplastic nevus syndrome, in each of which one member had ocular melanoma, are reported. These five families were examined within a 3-year period in one medical center. To date only five other families with such a combination have been reported. We suggest a causal relation between ocular melanoma and the familial dysplastic nevus syndrome.