Type A personality (hard driving, persistent, involved in work) was studied as a conditioner of the effects of quantitative work load and role ambiguity (stresses) on anxiety, depression, resentment, and heart rate (strains) among 73 male users of a university computer system that was approaching an imminent 23-day shutdown. Each respondent was his own control. Stress, personality, and psychological strain were assessed by questionnaire, and heart rate was measured. Change scores were then analyzed. Role ambiguity was positively associated with anxiety, depression, and resentment; subjective work load was positively associated only with anxiety. Anxiety was positively related to heart rate. The relationship between work load and anxiety was greatest for Type A persons, and a similar, but nonsignificant trend appeared for the effects of anxiety on heart rate. Response and respondent specificity are discussed.

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A review of 253 patients treated with enteral nutrition support via tube feedings is presented for the purpose of evaluating the incidence of complications. Thirty patients, (11.7%) experienced either gastrointestinal, (6.2%) mechanical (3.5%), or metabolic (2.0%) complications. The recognition and treatment of such complications are discussed and it is concluded that tube feedings are safely tolerated by most patients; however, constant attention must be exerted to either avoid or recognize such complications.

The satellite DNA (SATELLITE III) which is mainly represented in the female of Elaphe radiata (Ophidia, Colubridae) has been isolated and its buoyant density has been determined (delta equals 1.700 g cm-3). In situ hybridisation of radioactive complementary RNA of this satellite DNA with the chromosomes of different species has revealed that it is mainly concentrated on the W sex chromosome and its sequences are conserved throughout the sub-order Ophidia. From hybridisation studies these sequences are absent from the primitive family Boidae which represents a primitive state of differentiation of sex chromosomes. Chromosome analysis and C-banding have also revealed the absence of heteromorphism and of an entirely heterochromatic chromosome in the species belonging to the primitive family and their presence in the species of highly evolved families. It is suggested that the origin of satellite DNA (satellite III) in the W chromosome is the first step in differentiation of W from the Z in snakes by generating asynchrony in the DNA replication pattern of Z and W chromosomes and thus conceivably reducing the frequency of crossing-over between them which is the prerequisite of differentiation of sex chromosomes. Presence of similar sex chromosome associated satellite DNA in domestic chicken suggests its existence in a wider range of vertebrates than just the snakes.

Satellites visible in female but not in male DNA were isolated from the snakes Elaphe radiata (satellite IV, p = 1.708 g x cm-3) and Bungarus fasciatus (BK1 minor, p = 1.709 g x cm-3). The satellites cross hybridize. Hybridization of 3H labelled nick translated BK minor satellite DNA with the total male and female DNA and/or chromosomes in situ of different species of snakes revealed that its sequences are conserved throughout the snake group and are mainly concentrated on the W chromosomes. Snakes lacking sex chromosomes do possess related sequences but there is no sex difference and visible related satellites are absent. The following conclusions have been reached on the basis of these results. 1. The W chromosome associated satellite DNA is related to similar sequences scattered in the genome. 2. The origin and increment in the number of the W satellite DNA sequence on the W chromosome is assoicated with the heterochromatinization of the W. 3. Satellite sequences have become distributed along the length of the W and resulted in morphological differentiation of sex chromosomes. 4. Evolutionary conservation of W satellite DNA strongly suggests that functional constraints may have limited sequence divergence.