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Biomedical subjects

J Lewis

Publications and source records attributed to J Lewis.

At least 451 records · Page 25Linked to original sources
PubMed1975

Morphogenesis of the vertebrate limb.

Pattern formation in both the developing and the regenerating vertebrate limb can be understood in terms of the assignment of positional values to cells. The positional value may then control the selection of a course of cytodifferentiation as, say, muscle or cartilage. It is proposed that the proximodistal coordinate of positional value is extablished by a mechanism based on autonomous change with time in a 'progress zone' at the tip of the limb bud. The anteroposterior coordinate seems to be specified by a positional signal from an orgainzing region. Only cells in the progress zone respond to this signal. The change of character in the progress zone may be linked to cell division. It seems that each skeletal rudiment may initially be the same length, corresponding to the amount of tissue that leaves the progress zone during one cell cycle. The lengths on the skeletal elements are already specified shortly after exit from the progress zone, and are capable of very little regulation. The positional value may determine the pregramme of later growth. The relevance of the progress zone model to epimorphic regulation, and amphibian limb regeneration in particular, is discussed.

Animals↗
PubMed1975

"Hippie" hepatitis: an epidemiologic investigation conducted within a population of "street-people".

An epidemiologic investigation of viral hepatitis among "street-people" was conducted in Pittsburgh, PA in 1971. Among 146 individuals, 100 admitted to parenteral drug use and 73 (50%) had evidence of acute viral hepatitis. Counterelectrophoresis (CEP) and complement-fixation (CF) were used to test for type B antigen (HBS AG). Seventeen individuals (22%) had detectable HBSAG; 13 of these were clinically ill and admitted to drug use, Type B antibody (anti-HBS) was tested for by CEP and radioimmunoprecipitation (RIP). Thirty-five persons (29%), 15 of whom admitted to drug use and were ill, had detectable antibody by RIP; none had detectable antibody by CEP. None of those tested had both HBSAB and anti-HBS Evidence to support the hypothesis of sexual transmission of type B virus was found. Use of prophylactic gamma globulin in street-people populations is recommended.

Adolescent↗
PubMed1975

Circulating levels of fibrin/fibrinogen degradation fragment E in normal pregnancy, and in association with intrauterine growth retardation and perinatal asphyxia.

Levels of fibrin/fibrinogen degradation products have been measured by aspecific and sensitive radioimmunoassay for degradation fragment E (FgE) in pregnant patients. Maternal FgE levels rose from the 16th week reaching a plateau at the 36th week in normal pregnancy. There was no correlation between maternal FgE levels and maternal age, parity or the occurrence of perinatal asphyxia. A minority of patients (5 per cent) with evidence of intrauterine growth retardation showed prolonged elevation of FgE levels.

Asphyxia Neonatorum↗
PubMed1975

Chromosome banding studies in acute leukaemia at diagnosis.

Cytogenetic study by a chromosome banding technique has been attempted in 93 cases of acute leukaemia at diagnosis. Banding patterns were difficult to visualise in the bone-marrow chromosomes of patients with acute leukaemia because of the fuzzy appearance of the fixed metaphases. The proportion of patients with abnormal chromosomes was higher in acute lymphoblastic (ALL) than in acute myeloid (AML) leukaemia. Abnormalities were present in all cases of other cytological types. Hyperdiploidy was the most commonly found numerical error in both ALL and AML but a larger proportion of patients with ALL had hyperdiploidy in more than 30% of the cells. In ALL it was generally found that the higher the frequency of hyperdiploidy the greater was the number of chromosomes per cell. Hypodiploidy not attributable to random losses was found in only 6 patients. Clones identified by rearranged or marker chromosomes were found in all types of leukaemia. Clones marked by a 7q-chromosome, in which the break point was the same, were identified in 1 adult with ALL and 2 children with AML. The high frequency of randomly disturbed chromosomal breakage found in the bone-marrow chromosomes of a high proportion of the patients may be related to the disease process.

Adolescent↗
PubMed1975

Ultramicroscale determination of clinical chemical values for blood during the first four days of postnatal life.

Ultramicro procedures requiring 5-10 mul of serum or blood per analysis were used in determining blood constituents of healthy full-term newborns during the first four days of life. The resulting values appeared to be influenced by age, sex, and race. Values for total protein, albumin, urea nitrogen, and uric acid in serum decreased with time; serum inorganic phosphorus and whole-blood aldosaccharoses increased. Serum from females had higher values than that from males for total proteins, albumin, and inorganic phosphorus. The values for serum calcium and alkaline phosphatase were consistently higher in Negro than in white infants; values for uric acid were higher in the latter.

Age Factors↗