Biomedical subjects
Publications and source records attributed to M Lewis.
The amino acid sequences of the repressor and cro proteins of phages lambda, 434 and P22 are homologous, especially in a region in which repressor and lambda cro have a similar alpha-helix-turn-alpha-helix secondary structure. Model-building studies indicate that this structure is important in DNA binding, and we suggest it may be a common feature of many DNa-binding proteins.
Between 1976 and 1980, 32 patients with respiratory failure primarily due to neuromuscular disease were admitted on 34 occasions to the Respiratory Intensive Care Unit of the Johannesburg Hospital. Ninety-four per cent of patients admitted survived and were discharged from hospital. Ninety per cent of the survivors are fully rehabilitated and another 6.7% continue to improve. Despite a frequently prolonged illness, these patients have an excellent prognosis. Early diagnosis and management of respiratory failure in an intensive care unit are essential if their survival is to be ensured.
Two types of motor asymmetry, postural asymmetry and lateral head turning, were assessed in 3 groups of preterm infants, one of which had experienced respiratory distress syndrome (RDS) in the postnatal period. Results reveal that maintenance of a right postural asymmetry is present as early as 34 weeks conceptional age and is not disrupted by postnatal illness. Lateral head turning after midline placement was evident as early as 36 weeks conceptional age but was disrupted by physiologic condition. Infants who had experienced RDS had poor muscle tonus and did not assume the head right position even at 39 weeks conceptional age. These data argue that lateral responding may be affected by illness and that studies of preterm populations must evaluate postnatal medical condition when assessing both the short- and long-term outcomes of lateral asymmetries.
Mothers and their firstborn year-old infants (30 girls, 30 boys) were observed during two counterbalanced situations. In the noninteraction situation, mothers were not to initiate interaction; during interaction mothers were free to interact. Maternal and infant behavior were dependent upon both the situation examined and how it compared to the previous situation. During interaction, mothers directed more behavior toward their infants than during noninteraction; this effect was intensified when noninteraction preceded interaction. Infant looking and proximity-seeking were greater during interaction than during noninteraction, while the reverse was true for touching and vocalization. A decrease in the level of interaction resulted in increases in infant behavior, while the reverse transition was associated with a more variable pattern. Two models describe the interrelationships between changes in maternal and infant behavior. In a reciprocal system, increases by the mother in a given behavior, or in the general interactive level are related to decreases in infant behavior, and vice versa. In an incremental system, any change in maternal behavior is met by increases in infant behavior.
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The Chinese approach to old age is a blend of 4,000 years of recorded culture; a predominately agricultural past and present, and a thirty year old socialist government. Valuable insights are gained regarding aging in China through the description of Chinese elderly life in context with China's past and present. Pertinent questions are asked concerning the role of the elderly in China's future. Although lacking the references and methodology usually accompanying articles published in this journal, this paper is based on discussions with a number of Chinese living in the United States and Hong Kong, American experts on China, brief discussions with members of the Chinese Liaison Office (now the Chinese Embassy), an interview with Dr. Ma Hai-teh (George Hatem), a personal visit to China in the summer of 1978, and a review of literature on China. It offers an opportunity to become acquainted with the conditions of the elderly in another social and political system.
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A man was admitted to the Johannesburg Hospital with a history of fever, diarrhoea, and dry cough for four days. He began to produce bloodstained sputum and was found to have severe arterial hypoxaemia. Radiography showed widespread opacification over both lung fields, and the clinical and haemodynamic features were consistent with the adult respiratory distress syndrome. Serology for Leptospira canicola was positive. Despite antibiotics, supportive therapy, and ventilation the patient died. Necropsy excluded cardiac disease. This case shows that leptospirosis may cause the adult respiratory distress syndrome.
We analysed the results of the Widal test in the northern and eastern Transvaal in relation to bacteriologically confirmed cases of typhoid fever, patients suspected of having the disease, febrile patients without typhoid fever and healthy individuals. Titres of 1:200 or greater for either H or O agglutinins were recorded for 75,2% of patients with bacteriologically proven typhoid fever, 4,6% of healthy subjects residing in an endemic area and 7,5% of patients presenting with non-thyroid fevers. Age, sex and region were found to affect the percentage of positive tests recorded. Despite these failings, the Widal test was found to be of value in the diagnosis of typhoid fever. The concept of a diagnostic titre was considered unreliable, but considered in conjunction with the clinical picture, O or H agglutinin titres of 1:200 or more may be regarded as strong presumptive evidence of typhoid fever.
This study evaluates two procedures for the elimination of nocturnal thumbsucking in a 10-yr-old boy. The subject's mother recorded the occurrence of thumbsucking four times each night. Reliability checks were done twice a week by another family member. A plastic splint, usually employed to protect a damaged thumb, was placed on the subject's thumb at bedtime. The results showed that when the splint was used, the incidence of thumbsucking decreased from 100% of the checks made during baseline to 0% during intervention. Several naturally occurring and one planned reversal demonstrated the effectiveness of the splint in controlling thumbsucking.
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