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Biomedical subjects

J Scannell

Publications and source records attributed to J Scannell.

8 recordsLinked to original sources
PubMed2001

Is reduced dermatoglyphic a-b ridge count a reliable marker of developmental impairment in schizophrenia?

BACKGROUND: Finger and hand prints are formed during the late first and second trimester of foetal development, after which they remain unchanged. Their expression may be influenced by both genetic and environmental factors. Some studies have suggested that a reduced total finger ridge count (TFRC) and, in particular, a reduce total a-b ridge count (TABRC), may be associated with schizophrenia. AIM: To study these two variables in a large, ethnically homogenous sample and to compare our findings with those of other recent studies. METHOD: Finger and hand prints of 150 people with DSM-III-R schizophrenia were compared with those of 92 healthy controls. RESULTS: Patients had a reduced mean TABRC (P = 0.03) compared with controls. There was a significant (P=0.02) linear trend for lower TABRC and increasing incidence of schizophrenia (ORlineartrend = 1.3; 95%CI1.1-1.7), implying a continuous increase in the risk for schizophrenia with reduction in TABRC. No significant difference between groups was observed for TFRC. CONCLUSION: These results provide further evidence that dermatoglyphic abnormalities exist in at least some patients with schizophrenia and that the a-b ridge count may be a marker of disruption, probably environmental, that occurs when the developing brain may also be particularly vulnerable to such insult. These findings support the concept that some cases of schizophrenia may be due to adverse intrauterine events.

Adult↗
PubMed2001

Prey scan at random to evade observant predators.

Anti-predator scans by animals occur with very irregular timing, so that the initiation of scans resembles a random, Poisson-like, process. At first sight, this seems both dangerous (predators could exploit the long intervals) and wastefull (scans after very short intervals are relatively uninformative). We explored vigilance timing using a new model that allows both predators and prey to vary their behaviour. Given predators that attack at random with respect to prey behaviour, constant inter-scan intervals minimize predation risk. However, if prey scan regularly to minimize their risk from randomly attacking predators, they become more vulnerable to predators that initiate attacks when the inter-scan intervals begin. If, in order to defeat this tactic, prey choose extremely variable inter-scan intervals, they become more vulnerable to predators who wait for long intervals before launching attacks. Only if predators can monitor the variability of inter-scan intervals and either attack immediately (if variability is too low) or wait for long intervals to attack (if variability is too high) does the empirically observed pattern of Poisson-like scanning become the optimal prey strategy.

Animals↗
PubMed1982

The regulation of carbohydrate metabolism in animal cells: isolation of starch- and maltose-utilizing variants.

Chinese-hamster ovary (CHO-K1) cells can grow in medium in which glucose is replaced by either maltose, trehalose, or starch. This growth is due to the presence in the medium of serum enzymes which degrade these substrates to glucose. When the enzymes are inactivated by heat treatment, the cells no longer grow on these substrates but still grow on glucose. Medium containing heat-inactivated serum and the appropriate substrate in place of glucose has been successfully used to isolate starch- and maltose-utilizing variants of CHO-K1 cells.

Animals↗