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Biomedical subjects

P Johnson

Publications and source records attributed to P Johnson.

At least 595 records · Page 33Linked to original sources
PubMed1976

Amino-acid sequence of tropomyosin-binding component of rabbit skeletal muscle troponin.

The complete amino-acid sequence of rabbit skeletal troponin-T is reported. The protein consists of a single polypeptide chain of 259 amino acids; it has an acetylated amino terminus and a molecular weight of 30,503. The sequence was determined by manual and/or automated Edman degradation techniques on the six fragments obtained after cleavage with cyanogen bromide. The larger fragments were further digested with trypsin, chymotrypsin, alpha-lytic protease, thermolysin, or pepsin to obtain smaller fragments suitable for manual sequencing. About 50% of the residues are charged at neutral pH with highly acidic amino-terminal (residues 1-39) and highly basic carboxyl-terminal regions (residues 221-259). Predictions of secondary structure indicate 37% helical content with two long sections (residues 80-102 and 122-146) in that portion of the molecule implicated in binding to tropomyocin. Two of the three phosphorylated sites in the molecule are located at serine-1 and serine-149 or -150. The sequence about the latter site resembles somewhat the phosphorylase kinase phosphorylation sites in phosphorylase alpha and troponin-I.

Amino Acid Sequence↗
PubMed1976

Evaluation of amniotic fluid for aerobic and anaerobic bacteria.

Studies of 117 pregnant women, 83 at term, were instituted to determine the bacteriologic state of amniotic fluid, utilizing both standard aerobic and anaerobic technics. A high association of postpartum infection was found in women who had long periods of premature reptured membranes and many vaginal examinations. Significant organisms including anaerobes, were isolated in many of these instances. Based on the findings of these studies, it is recommended that amniocentesis for aerobic and anaerobic cultures be done when membranes have been ruptured for 8 hours or more, and when the patient has had seven or more vaginal examinations during the course of labor.

Adolescent↗
PubMed1976

Supratentorial haemangioblastoma with polycythaemia.

A case is reported of a 21 year old man with polycythaemia and a vascular frontal lobe tumour that was histologically compatible with the diagnosis of haemangioblastoma. On review of the English literature no case could be found of polycythaemia associated with supratentorial haemangioblastoma.

Adult↗
PubMed1976

Studies in diabetic pregnancy. I. Serum lipids.

The serum lipid values at different stages of pregnancy in twenty-six pregnany diabetic women attending a special antenatal clinic at the Department of Obstetrics and Gynecology, were compared with the corresponding values in four control series composed of non-diabetic pregnant women. Control series were studied at weeks 10, 22, 34 and after delivery, respectively. Serum triglycerides were higher in the diabetic women at week 10 (p less than 0.01), week 34 (p less than 0.05) and after delivery (p less than 0.05). Furthermore, in the diabetic women, infant birth weights were correlated (r=0.52, p=0.05) with maternal serum triglyceride values at week 31. Women with the highest serum triglyceride values (greater than 250 mg/100 ml) were delivered of infants with a higher birth weight (p less than 0.05) than those women with lower serum triglyceride values (less than 250 mg/100 ml). Intra-uterine deaths (n=4) were not related to maternal serum triglyceride values, but mean blood glucose values (during the whole pregnancy) were higher (p less than 0.001) in mothers with intra-uterine deaths. Elevated plasma free fatty acids (FFA) in the diabetic mother would be a possible cause for elevated serum triglycerides through increased liver triglyceride synthesis, while in the fetus an excess of plasma FFA (passing through the placental barrier) together with normal or elevated plasma insulin would be a likely explanation for increased triglyceride synthesis in adipose tissue and thereby of increased fat depots and body weight.

Birth Weight↗
PubMed1976

Cardiorespiratory status of erythroblastotic newborn infants: III. Intravascular pressures during the first hours of life.

We measured aortic and central venous pressures beginning soon after birth in 40 prematurely born infants with moderate or severe erythroblastosis fetalis, including 13 with severe and 10 with mild hydrops fetalis. All but four were asphyxiated at birth and this affected intravascular pressures. Before resuscitation, aortic or central venous pressure or both were elevated in more than one third. All but two of the remaining infants had normal initial pressures. Following resuscitation which relieved acidosis, hypoxia, and anemia, but did not reduce blood acidosis, hypoxia, and anemia, but did not reduce blood volume, the high pressures usually fell to normal and occasionally to subnormal levels, normal pressures fell to subnormal in almost one half, and those with initial subnormal pressures remained hypotensive. In all, 40% were hypotensive after resuscitation; treatment with blood volume expanders consistently returned these pressures to normal. Only two of the 13 severely hydropic infants and none of the mildly hydropic had findings indicative of hypervolemia and myocardial failure which persisted after treatment of asphyxia.

Animals↗
PubMed1975

Breathing and sucking during feeding in the newborn.

Eighteen normal full-time infants aged from 1-10 days were fed both normal saline and distilled water from a conventional feeding bottle. Fifty-four sets of observations were made when 44 infants were fed both cow's milk (Half Cream Cow & Gate) and expressed human milk. During feeding, measurements were made of breathing, sucking, and the flow of milk from a feeding bottle which incorporated an electromagnetic flowmeter transducer. Integration of the flow of milk measured the volume of milk swallowed by the baby. The results suggest that the patterns of feeding and breathing differ in some infants when different fluids are given to them.

Age Factors↗
PubMed1975

Complement dependence of localisation of aggregated IgG in germinal centres.

In vivo decomplementation of mice with cobra factor completely prevented trapping of aggregated human IgG within splenic germinal centres. Observations of the intrasplenic position of the aggregated material within 8 hr of its injection into normal and decomplemented mice suggest that the early phase of localisation in germinal centres depends on binding to lymphocyte C3 receptors.

Animals↗
PubMed1975

Studies in cholestasis of pregnancy.

Forty-one pregnant women with pruritus, in whom cholestasis was verified by the presence in their serum of an abnormal lipoprotein, lipoprotein-X (LP-X), were divided into two clinical groups, pruritus gravidarum (PG) (n=20) and hepatosis of pregnancy (HP) (n=21) in relation to serum bilirubin (below and above 1.2 mg/100 ml, respectively) and/or SGOT, SGPT (below and above 50 units/l, respectively). In HP, but not in PG, serum lipids, i.e. cholesterol, phospholipids, triglycerides, pre-beta-lipoproteins (very-low-density lipoproteins), and low-density lipoproteins were increased and high-density lipoproteins decreased when compared with suitable controls. Serum lipids were elevated in proportion to the derangement in the liver function tests, alkaline phosphatase, SGOT, and SGPT. The occurrence of LP-X was inversely related to HDL cholesterol, suggesting a causal relationship between HDL lipid metabolism and the presence of LP-X. Serum TIBC, Simplastin A, and serum iron were elevated in HP in relation to the degree of deterioration of liver function tests. Some of these changes in serum in cholestatic pregnancy may partially (serum triglycerides and pre-beta-lipoproteins) or completely (TIBC and Simplastin A) be explained by an enhanced estrogen influence in promoting increased liver lipid/protein metabolism.

Alanine Transaminase↗