[DNA diagnostics in dementia]. / DNA-diagnostiek bij dementie.

- Thanks to next-generation sequencing several genes can be examined in one go. Since this method has been introduced, the possibilities for DNA diagnostics in patients with dementia have increased tremendously in recent years.- DNA diagnostics is indicated for patients with an Alzheimer's disease diagnosis before they are 60 years old, for all patients with frontotemporal dementia and for patients with a positive family history.- For 15% of the patients who visited the Alzheimer centre of the VUmc, in Amsterdam, the Netherlands DNA diagnostics indicated a clear monogenic cause.- Although a hereditary cause of dementia is often a hard message for patients and their families, this knowledge often provides them with more clarity with respect to the diagnosis and the course of the disease. In addition, family members may choose to carry out presymptomatic DNA testing.- The therapeutical consequences of DNA diagnostics are currently minimal; several studies are being carried out internationally in this area.

Doping concentration of GaN nanowires determined by opto-electrical measurements.

The influence of n-doping on the electrical transport properties of GaN nanowires is investigated by photoconductivity measurements on wires with different diameters. The electrical transport in nanowires is extremely sensitive to the wire diameter because of the size dependent barrier for surface recombination. This effect is used to determine the doping level of the nanowires and to complete and consolidate our previously developed surface recombination model for GaN nanowires.

CT density measurement of bone graft within an intervertebral lumbar cage: increase of hounsfield units as an indicator for increasing bone mineral content.

Radiographic assessment of lumbar interbody fusion is difficult, especially in the presence of cages and metal artifacts. The purpose of this study is to assess whether impacted bone chips in intervertebral lumbar cages show a tendency toward increased attenuation on postoperative computed tomography (CT) scans as a sign of ongoing revascularization and increased bone mineral content inside the cage. Twenty-one patients with single- or double-level lumbar fusion underwent CT scanning 1-44 months postoperatively. CT attenuation of bone inside the cage was measured with Hounsfield units. Intra- and interobserver variability were evaluated. Regression analysis showed an increase of 7.5 HU/month postoperatively for an initial value of 615 HU. Intra- and interobserver variability showed an interclass coefficient of 0.97. CT attenuation of bone graft inside an intervertebral cage increases in the postoperative period. Hounsfield unit measurement can be performed with a high degree of accuracy and reproducibility and may in the future provide a useful tool in studying cage contents in individual patients.

A partial BRCA1 sequence homology mapping to 4q28.

Using a BRCA1 cDNA probe in Southern analysis, we detected a sequence of 348 bp on 4q28 that is homologous to the 3' end of BRCA1. A 28-kb sequence contig has been assembled spanning the homologous region, which we designated BRCA1-h. An open reading frame was identified encoding a sequence of 82 amino acids; 22 of the last 23 amino acids are identical to the last 23 residues of BRCA1. BLAST-searches, RT-PCR and RACE-experiments have been unable to provide evidence that BRCA1-h is part of an expressed gene.

Absence of evidence for a familial breast cancer susceptibility gene at chromosome 8p12-p22.

Several recent studies indicate that the majority of families with five or fewer cases of breast cancer and no cases of ovarian cancer are not due to BRCA1 or BRCA2. It has been proposed that a further breast cancer susceptibility gene that may account for some of these families is located on chromosome 8p12-p22. We have identified 31 site-specific breast cancer families that have a greater than 80% posterior probability of being due to genes other than BRCA1 or BRCA2. These families have been examined for linkage to 8p12-p22 using markers flanking the putative location of the gene. The overall multi-point LOD score is strongly negative across the whole 44 cM. The individual multi-point LOD score is negative in 23 families and only exceeds 0.5 in a single family (with a multi-point LOD score of 1.22). The maximum heterogeneity LOD score was 0.03 at marker D8S136 with estimated proportion linked (alpha) of 3% (95% CI 0 - 30%). These data do not lend support to the hypothesis that chromosome 8p12-p22 harbours a familial breast cancer susceptibility gene. Oncogene (2000) 19, 4170 - 4173

[Percutaneous gallbladder drainage a good treatment in patients with acute cholecystitis and and poor clinical status]. / Percutane galblaasdrainage goede behandeling bij patiënten met acute cholecystitis en slechte klinische toestand.

OBJECTIVE: To evaluate the results of ultrasound-guided percutaneous cholecystostomy in patients with increased surgical risk. SETTING: University Hospital Rotterdam. DESIGN: Retrospective. MATERIAL AND METHOD: 24 patients with acute cholecystitis and an increased surgical risk were treated with ultrasound-guided percutaneous cholecystostomy. Cholecystostomy was successfully performed in all patients. RESULTS: 23 patients showed clinical and biochemical improvement within one week. Minor complications were encountered in three cases (12%) which were treated conservatively. 16 patients suffered from calculous cholecystitis. One patient died after the cholecystostomy from an aspiration pneumonia. Cholecystectomy was performed at a later stage in six patients. One of these patients died six days after surgery from a myocardial infarction. Seven patients had percutaneous or endoscopic therapy for gallstones. In two cases no further therapy for gallstones was performed. Eight patients had acalculous cholecystitis. Four patients, suffering from cholangiocarcinoma and malignant obstruction of the cystic duct, subsequently underwent cholecystectomy (two patients) and percutaneous sclerotherapy of the gallbladder (two patients). Percutaneous cholecystostomy alone sufficed for the four remaining patients with acalculous cholecystitis. CONCLUSION: Percutaneous cholecystostomy for high-risk patients with acute cholecystitis is a low-invasive procedure with low morbidity and mortality. The catheter in the gallbladder offers diagnostic and therapeutic possibilities and does not interfere with cholecystectomy at a later stage. In some cases of acalculous cholecystitis drainage of the gallbladder is the only therapy needed.

Influence of radiologically and cytologically assessed distant metastases on the survival of patients with esophageal and gastroesophageal junction carcinoma. The Rotterdam Esophageal Tumor Study Group.

BACKGROUND: Distant metastasis in carcinoma of the esophagus and gastroesophageal junction is associated with a poor survival after resection. To improve the selection of patients for surgical and nonsurgical treatment, this study determined the influence on survival of distant metastases, as assessed on radiologic studies or proven on cytologic studies. METHODS: During the period 1989-1990, 135 patients were referred to the institution in this study. On ultrasonographic or computed tomographic studies, distant metastases were suspected in 62 patients and were absent in 73 patients. In 33 patients, metastases were proven cytologically; 32 of these patients subsequently were excluded from surgery. Twelve other patients were unfit for surgery because of their general condition. The remaining 91 patients had surgery; 77 patients had transhiatal esophagectomy, and the tumor was unresectable in 14 patients. RESULTS: The 2-year survival rate for all patients in whom distant metastases were suspected on radiologic studies was 11.2%, and it was 44.3% for patients without metastases on these studies (P < 0.001). For patients with cytologically proven metastases, the 2-year survival rate (3%) was lower than for patients in whom distant metastases were suspected on radiologic studies but not cytologically confirmed (21.1%) (P < 0.001). There was no statistically significant difference in survival between this last group of patients and those without metastases identified by radiologic studies (P = 0.87). After resection, the 2-year survival rate decreased from 53.9% to 0% when distant metastases were present on histopathologic studies of the resected specimen (P = 0.04), and there was no significant difference in survival between patients with distant metastases suspected or absent on preoperative radiologic studies (P = 0.47). CONCLUSIONS: Surgery should be avoided in patients with cytologically proven distant metastases because the expected survival rate is low and surgery does not seem to be a life-prolonging procedure in these patients; however, patients should not be excluded from surgery on the basis of metastases identified by radiologic studies alone.

Symbiotic association of Psalteriomonas vulgaris n. spec. with Methanobacterium formicicum.

The free-living anaerobic flagellate Psalteriomonas vulgaris n. spec. is described. The organism has four flagella of equal length which arise immediately subapically to the anterior part of the cell, within the apex of the ventral groove. The ultrastructural organization of the mastigont system and the ventral groove show the characteristics of the genus Psalteriomonas. The cells harboured methanogenic endosymbionts which were associated with hydrogenosome-like organelles in which hydrogenase could be localized. The methanogenic bacteria were isolated and identified as Methanobacterium formicicum. After addition of 5% O(2) to the cultures, the cells lost the methanogenic endosymbionts. P. vulgaris lacked cytochrome oxidase and catalase but contained superoxide dismutase.