A comparison of eye movement behavior of inexperienced and experienced drivers in real traffic environments.

PURPOSE: The importance of the visual system as the input channel for sensory information necessary when driving is often stated. There are several reports on differences in visual search strategies between experienced and inexperienced drivers, as well as in relation to the roadway. However, the results are ambiguous and are not sampled by similar procedures. Based on previous findings, the aim of the present study was to gain further knowledge on these differences by testing the hypotheses that inexperienced drivers, in comparison to experienced drivers, fixate closer to the vehicle, fixate more often on in-vehicle objects, spread their fixations less along the horizontal meridian, fixate more often on relevant traffic cues, and fixate more often on objects classified as potential hazards. METHODS: Data from eye-tracker recordings of visual search strategies of the driver in real-world traffic were used for the analyses. RESULTS: The results confirmed all stated hypotheses regarding differences between inexperienced and experienced drivers, with the exception of fixations closer to the vehicle, in which ambiguous results were found. CONCLUSIONS: The present study provides normative data for the understanding of the development of visual search strategies among drivers. The methodology used in the present study, i.e., to combine a quantitative analysis with a qualitative analysis proved, to be useful to compare visual search strategies among inexperienced and experienced drivers.     

Neurohormonal peptide immunoreactive cells in mucinous cystadenomas and cystadenocarcinomas of the ovary

Summary In 144 benign mucinous cystadenomas of the ovary, 33 mucinous cystadenomas of borderline malignancy and 64 mucinous cystadenocarcinomas, the incidence of tumours containing argyrophil (and probably endocrine) cells was 18%, 33%, and 53%, respectively. The results of a semiquantitative assessment of the number of argyrophil cells in each individual tumour indicates that the greatest numbers occurred in the cystadenocarcinomas. As, however, the tumour cell density was larger in the cystadenocarcinomas than in the cystadenomas, and as the argyrophil cells often had a patchy distribution in the tumour epithelium, the incidence figures are unreliable. In addition, visualization of the argyrophil cells depends on an adequate fixation which is difficult to achieve in the routine processing of large tumour specimens.Many argyrophil cells in the cystadenocarcinomas displayed immunoreactivity with antisera raised against gastro-entero-pancreatic (GEP) neurohormonal peptides. In ten such tumours immunohistochemical evidence was obtained for the presence of the following neurohormonal peptides in the tumour cells: somatostatin, glucagon, gastrin/CCK, neurotensin, and enkephalin. Four of these ten cystadenocarcinomas were multihormonal, in that three contained two cell populations storing GEP neurohormonal peptides, and one tumour even three such populations. In the benign cystadenomas, however, no immunoreactive tumour cells were found. In those of borderline type, only two harboured immunoreactive cells. In both cases the tumour cells stored gastrin/CCK.The general appearance of the epithelium in the mucinous tumours — a continuous single-cell layer of mucin-producing cells intermingled with argyrophil cells of open type — and the spectrum of neurohormonal peptides observed, indicate an origin from the foregut endoderm.This investigation was supported by grants from the Swedish Medical Research Council (Projects No. 4X-4499 and 12X-718), the Swedish Cancer Society (Project No. 805), the Cancer Research Fund of Malmö General Hospital, and the Medical Faculty at the University of Lund     

Argyrophil and beta-endorphin immunoreactive cells in focal islet-cell adenomatosis and insulin-producing islet-cell adenomata

Pancreatic tissue from 3 cases of hyperinsulinemic hypoglycemia was examined using histochemical and immunoperoxidase staining techniques. The insular lesions present were adenomatosis and insulin-producing islet-cell adenomata. The great majority of the islet parenchymal cells in these lesions were reactive with antibodies to pro-insulin, C-peptide, and insulin. A variable number of islet cells was found to react with beta-endorphin antiserum in all 3 cases, while the reaction with antiserum against the neural tissue marker antigen, S-100, was restricted to the cases with islet-cell adenoma. Argyrophil parenchymal cells were present in focal adenomatosis but almost absent in insulomata. These results suggest that various lesions of the endocrine pancreas causing hypoglycemia can be distinguished by means of specific histo- and immunocytochemical methods because of differences in the distribution of characteristic cellular antigens.     

Effect of cyclic AMP on the isolated human oocyte -- cumulus complex

Cyclic AMP (cAMP) is one of the key regulators of the resumptionof oocyte meiosis (oocyte maturation) in several mammalian species.In this study we have examined the role for cAMP in regulationof spontaneous maturation of human oocytes. Oocytes were obtainedin connection with gynaecological operations and cultured for24 or 48 h. A significantly larger proportion (77%) of oocytescultured in the presence of 1 mM dibuturyl-cAMP (dbcAMP) for24 h were arrested in meiosis compared to oocytes cultured incontrol medium (25%). In addition, dbcAMP stimulated progesteroneaccumulation during 48 h of incubation and inhibited monolayerformation of the cumulus cells attached to the oocyte. The datapresented in this study demonstrate that dbcAMP delayed thespontaneous maturation of human oocytes and stimulated progesteroneproduction by the cumulus cells. These results indicate thatcAMP may be important also for regulation of meiosis in humanoocytes and confirm results obtained in other species.     

Cervicogenic headache: Clinical presentation, diagnostic criteria, and differential diagnosis

Since the first attempt at setting down diagnostic criteria was made in 1990, there has been considerable progress in the field of cervicogenic headache (CEH). CEH makes up a “final common pathway” for several neck disorders that may originate at different levels of the cervical spine. CEH has been defined as being mainly a unilateral headache without sideshift; it may accordingly also be bilateral. Anesthetic blockades are mandatory for scientific work. If the pain is bilateral, it is particularly important that blockades are carried out. Pain stemming from the neck usually spreads to the oculofrontotemporal area. The most characteristic features are symptoms and signs of neck involvement (such as mechanical precipitation of attack, and so forth). Migraine without aura and tension-type headache are the most difficult differential diagnosis problems.     

Malignant melanoma of the skin: risk, tumour characteristics and mortality in adult twins born in Norway between 1905 and 1945 - a cohort study

In this cohort study, data on the observed reduced incidence of malignant melanoma (MM) of the skin in twins compared with a control group were related to tumour characteristics and all-cause mortality. The twin cohort consisted of 20 926 individuals and the control group included individuals picked at random and matched to the twin cohort with respect to age, sex and place of birth. The cohorts were linked to the Cancer Registry of Norway and all cases of MM diagnosed from 1960 to 1999 were followed until October 2003. The mean observation time from diagnosis to death or censoring was 10.9 years (SD, +/-8.5 years). The relative risk of MM for the twins was 0.68 [95% confidence interval (CI): 0.55, 0.83]. No statistically significant difference was found in the distribution of histopathological subtypes or pathological stage between the cohorts. The crude all-cause mortality risk for the twin cases was 0.79 (95% CI: 0.58, 1.07). Stratified analysis indicated effect modification by gender on all-cause mortality risk (Breslow-Day test of homogeneity P=0.02). Multivariate analysis was performed separately for men and women. The adjusted mortality risk ratio for male twin cases was 1.11 (95% CI: 0.75, 1.65) and for female twin cases 1.05 (95% CI: 0.61, 1.8). The twins had a lower relative risk of MM compared with the control group, but similar tumour characteristics and all-cause mortality.     

Openers of ATP-dependent K<Superscript>+</Superscript>-channels protect against a signal-transduction-linked and not freely reversible defect of insulin secretion in a rat islet transplantation model of Type 2 diabetes

Aims/hypothesis We tested whether chronic overstimulation by levels of hyperglycaemia commonly found in Type 2 diabetes can irreversibly desensitise beta cells and, if so, whether desensitisation relates to the reduction of insulin content and/or the number of beta cells.Methods We transplanted islets from Wistar-Furth rats under the kidney capsule to neonatally streptozotocinised recipients. Recipients received daily vehicle, diazoxide (100 mg/kg) or the selective activator of beta cell type K⁺-ATP channels 6-chloro -3-(1-methylcyclopropyl) amino-4H-thienol [3,2-e]-1,2,4-thiadiazine 1,1-dioxide (NN414) (3 mg/kg) intragastrically for at least 9 weeks. Endpoint measurements were made exactly 7 days after cessation of treatment.Results Blood glucose did not differ between groups (mean of total: 13.2±1.4 mmol/l). C-peptide levels were significantly depressed in drug- versus vehicle-treated rats 3 to 4 hours after the last gastric tubing event, but not at endpoint. Insulin responses to 27 mmol/l glucose from perifused grafts were not significant after vehicle (median increment 18×10^–3 µU·islet^–1·min^–1) but were significant per se and versus vehicle in the diazoxide and NN414 groups (median 107 and 83×10^–3 respectively). Rising second-phase secretion was seen only in the drug-treated groups. Stimulation by 25 mmol/l KCl, together with 0.5 mmol/l 3-isobutyl-1-methylxanthine and 3.3 mmol/l glucose, was enhanced in the drug-treated groups (p<0.05 versus vehicle). Graft insulin content did not differ between groups, nor did percentage of beta cells (between 67 and 68% of endocrine cells).Conclusions/interpretation Chronic overstimulation by moderate hyperglycaemia damages signalling events including those required for glucose-induced insulin secretion. This signal transduction defect occurs in the absence of any effect on islet macro-morphometry or insulin stores.Abbreviations IBMX 3-isobutyl-1-methylxanthine - IHC immunohistochemical - K⁺-ATP channels ATP-sensitive potassium channels - NN414 6-chloro -3-(1-methylcyclopropyl) amino-4H-thienol [3,2-e]-1,2,4-thiadiazine 1,1-dioxide - PP cells pancreatic polypeptide cells