Search PubMed⌕ Search

Biomedical subjects

P Cooper

Publications and source records attributed to P Cooper.

At least 127 records · Page 7Linked to original sources
PubMed1989

Feeding efficiency of premature neonates.

The purpose of this study was (a) to investigate the validity of the revised Neonatal Oral Motor Assessment Scale (NOMAS) in discriminating between efficient and inefficient feeders in a sample of high-risk premature neonates and (b) to identify significantly different oral motor behaviors in the two groups. The revised NOMAS rates normal and abnormal characteristics of nutritive and nonnutritive sucking. The 26 subjects were classified by the amount of liquid they consumed during the first 5 min of feeding. The findings demonstrated that both nutritive and nonnutritive sucking scores were higher in the efficient feeders than in the inefficient feeders and that the revised NOMAS scores accurately classified the two groups. Characteristics that were significantly associated with inefficient feeding were lack of rhythm, disorganization in jaw and tongue movements, and pauses of more than 6 sec. Often, these responses appeared to be related to respiratory patterns.

Bottle Feeding↗
PubMed1989

Severe pneumococcal infection: a one year survey.

Invasive pneumococcal infection is a major health problem with considerable mortality. In most patients the diagnosis is relatively straightforward but this study points out that in many, especially children, it is difficult because of a lack of clinical signs of septicaemia. While chronic respiratory disease is a major predisposing factor, malignancy and immune disorders are also common underlying features. Certain risk groups may benefit considerably from vaccination. The treatment of established infection is now complicated by the emergence of resistant strains, but penicillin remains the mainstay of therapy.

Adolescent↗
PubMed1989

Chloroquine and onchocerciasis.

My original elective proposal was to study the prevalence and nature of onchocerciasis or 'river blindness' along the Canandé River in Esmeraldas province of Ecuador (Cooper, 1986). However, unknown to me, this study was completed and published before I arrived (Guderian et al, 1987). Fortunately, on arrival I was able to join the same group on a study of the efficacy of chloroquine in the control of onchocerciasis.

Biopsy↗
PubMed1988

Changes in protein synthesis induced in tomato by chilling.

Impaired chloroplast function is responsible for nearly two-thirds of the inhibition of net photosynthesis caused by dark chilling in tomato (Lycopersicon esculentum Mill.). Yet the plant can eventually recover full photosynthetic capacity if it is rewarmed in darkness at high relative humidity. As a means of identifying potential sites of chilling injury in tomato, we monitored leaf protein synthesis in chilled plants during this rewarming recovery phase, since changes in the synthesis of certain proteins might be indicative of damaged processes in need of repair. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins pulse labeled with [(35)S]methionine revealed discrete changes in the pattern of protein synthesis as a result of chilling. A protein of M(r) = 27 kilodaltons (kD), abundantly synthesized by unchilled plants, declined to undetectable levels in chilled plants. Reillumination restored the synthesis of this protein in plants rewarmed for 8 hours. Peptide mapping analysis showed the 27 kD protein to be the major chlorophyll a/b binding protein of the photosystem II light-harvesting complex (LHCP-II). The identity of this protein was confirmed by its immunoprecipitation from leaf extracts by a monoclonal antibody specific for the major LHCP-II species. While chilling abolished the synthesis of the major LHCP-II species, it also induced the synthesis of an entirely new protein of M(r) = 35 kD. The protein was synthesized on cytoplasmic ribosomes, and two-dimensional polyacrylamide gel electrophroesis showed it to exist as a single isoelectric species. This chilling-induced 35 kD protein is structurally distinct from the 27 kD LHCP-II and appears to be synthesized specifically in response to low temperature. While the 35 kD protein was found not to be associated with the chloroplast thylakoid membrane, chilling did cause selective changes in thylakoid membrane protein synthesis. The synthesis of two unidentified proteins, M(r) = 14 and 41 kD, and the beta-subunit of the chloroplast coupling factor were substantially reduced after chilling. These losses may provide clues as to the causes of the overall reduction in net photosynthesis caused by chilling.

Journal Article↗
PubMed1988

Thrombovascular disease and familial plasminogen deficiency: a report of three kindreds.

We report three kindreds in whom plasminogen deficiency was associated with thrombosis and in whom the ratio of functional and immunological values of plasminogen was consistent with type I deficiency. An additional subject with plasminogen deficiency is also described. The three propositi presented with venous thrombotic disease. The fourth subject presented with a thrombotic stroke. Investigation of family members in three of these four cases revealed other subjects who were found to have low levels of plasminogen and who were asymptomatic. The pattern of inheritance appears to be autosomal dominant. In one woman, plasminogen levels were shown to rise to within the normal range during pregnancy and returned to low levels after delivery. A total of eight pregnancies were reviewed in our series and no thrombotic events occurred.

Adult↗
PubMed1988

Fibrinolysis during normal human pregnancy: complex inter-relationships between plasma levels of tissue plasminogen activator and inhibitors and the euglobulin clot lysis time.

Although it has been previously considered that blood fibrinolytic capacity is reduced during pregnancy, this has been disputed. Also the mechanisms underlying any change in fibrinolysis in pregnancy require clarification. We have therefore measured the plasma activity of tissue plasminogen activator (t-PA) and inhibitors (t-PAi) and the concentration of the pregnancy specific inhibitor (PA12) antigen, as well as the euglobulin clot lysis time (ECLT) during normal pregnancy. Plasma concentrations of fibrinogen, plasminogen, fibrin(ogen) degradation products (FDP) and cross-linked products (D-dimer) were also monitored. We confirm a marked reduction of the fibrinolytic activity of the plasma euglobulin fraction from the second trimester, and a parallel reduction in t-PA and increase in t-PAi activities, with rapid return to non-pregnant levels post-partum. In contrast, PAI2, whilst undetectable in non-pregnant control plasma, was already measurable in the first trimester, increased through pregnancy, and remained at a high concentration up to at least 48 h post-partum. Fibrinogen and plasminogen concentrations rose progressively through pregnancy and FDP and D-dimer were frequently detectable in late pregnancy plasma. Changes in the ECLT and plasma t-PA and t-PAi activities in pregnancy cannot therefore be directly related to the concentration of PAI2 antigen. Also, despite the apparent marked reduction in fibrinolytic capacity fibrin(ogen) breakdown products are frequently present in increased plasma concentrations in late pregnancy.

Female↗
PubMed1987

Evidence for a nonprolactin, non-growth-hormone mammary mitogen in the human pituitary gland.

To determine whether the human pituitary contains a previously unidentified, nonprolactin (non-hPRL), non-growth-hormone (non-hGH) factor capable of stimulating mammary development, we tested the effects of whole human pituitary extract (hPE) and pituitary extracts depleted of hPRL and hGH ("stripped hPE") in hypophysectomized, castrated estradiol (E2)-treated male rats and rhesus monkeys. Both whole and stripped hPE significantly stimulated rat mammary development (mean scores = 3.3 and 2.0, respectively, on a scale ranging from 0 to 4) in comparison with controls (mean score = 1.0). Mammary development was not due to minute concentrations of hGH or hPRL remaining in stripped hPE because 30- to 100-fold higher concentrations of hGH (Genentech) and 1000-fold higher concentrations of hPRL were required to stimulate significant mammary development. Non-pituitary extracts of human ovary, muscle, and serum, and bovine serum albumin did not stimulate rat mammary gland growth. Trypsin destroyed the mammary mitogenic activity of whole hPE, indicating that the unidentified factor is likely a protein. Mammary growth and development were also stimulated in hypophysectomized, E2-treated monkeys by stripped hPE (mean histological score = 3.25 vs. 1.35 in control animals). Monkeys receiving stripped hPE had undetectable levels of hGH and hPRL in serum sampled over a 24-hr period. These findings suggest that the human pituitary contains a non-hPRL, non-hGH factor that stimulates mammary growth and may be important in normal mammary growth and development and perhaps in breast cancer.

Animals↗
PubMed1987

Intracellular localization of heat shock proteins in maize.

The intracellular distribution of the maize root heat shock proteins (hsp) was studied as a step toward understanding their physiological function. Linear sucrose density centrifugation was employed to separate organelles so the relative quantities of hsp in different subcellular compartments could be analyzed in a single preparation. Gradient fractions were assayed for the presence of hsp by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and for marker enzyme activities. Analyses of 15 to 60% gradients showed five hsp to be organelle associated. Hsp 25 and 72 were in fractions containing closely equilibrating Golgi and endoplasmic reticulum marker activities, while hsp 18, 29, and 72 were in fractions containing overlapping plasma membrane, mitochondria, and glyoxysomal marker activities. Hsp larger than 72 kilodaltons were not present in gradient fractions. A second fractionation scheme achieved better separation of the two sets of closely equilibrating organelles. When a 13,000g centrifugation step to remove mitochondria was employed prior to gradient centrifugation, hsp 29 was absent from the gradient fractions. If the buoyant density of the endoplasmic reticulum was shifted by either maintaining the ribosomes on the membrane or removing them, a corresponding shift in the equilibrium positions of hsp 25 and 72 occurred. Hsp 18 and 70 remained in plasma membrane-containing fractions irrespective of these treatments.

Journal Article↗
PubMed1987

Adenocarcinoma of the endocervix--a histochemical study.

The histological distinction between endometrial and endocervical adenocarcinoma may present diagnostic difficulties. Several reports have suggested that differences in the histochemical staining of the tumours may indicate their histogenesis. In this paper we have compared the staining properties of 20 endocervical adenocarcinomas (14 invasive and six in situ) with 12 cases of endometrial adenocarcinoma. Unequivocal examples were used where the site of origin was not in doubt. Sections were stained using a monoclonal antibody to carcinoembryonic antigen (CEA), alcian blue at pH 1.0 and pH 2.5, PAS-diastase and toluidine blue. The results were graded by two pathologists and results compared. Three poorly differentiated invasive endocervical tumours were completely negative for CEA. Seventeen out of the remaining 20 endocervical tumours and 7/12 endometrial adenocarcinomas showed a non-specific apical staining pattern. This also occurred in normal and dysplastic endocervical glands. Intense intracytoplasmic staining for CEA was found in 7/14 invasive and 3/6 in situ endocervical adenocarcinomas. Normal endocervix never showed this staining reaction. However, 4/12 endometrial tumours showed a similar pattern. Mucin stains showed no specific staining pattern for either tumour. In an individual case where the site of origin is in doubt, histochemical methods are of little value in confidently resolving the problem.

Adenocarcinoma↗
PubMed1987

Pitfalls in the CT diagnosis of atlantoaxial rotary subluxation.

CT was used to examine six patients with clinically evident atlantoaxial rotary fixation, two patients with torticollis, and six normal subjects who had turned their heads to the side as far as voluntarily possible. The CT appearances of the atlantoaxial complex were identical in all three groups. To differentiate these groups, we propose a functional scan through C1-C2 in which patients are scanned initially as they present, with their heads fixed in lateral rotation. Subsequent scans are obtained with their heads turned to the maximum contralateral rotation. CT scans in patients with atlantoaxial rotary fixation demonstrate no motion at C1-C2 during this maneuver, while those in patients with transient torticollis show a reduction or reversal of the rotation of C1 on C2.

Adolescent↗
PubMed1986

Effects of paradoxical sleep deprivation in the rabbit.

The effects of nonpharmacologically-induced deprivation of paradoxical sleep for a 24 hour period were studied in rabbits. Response characteristics commonly associated with the deprivation procedure in other species were observed, as well as features apparently peculiar to the rabbit. Like other mammals, rabbits: (1) show increased attempts to experience PS during the deprivation procedure relative to the baseline occurrence of PS; (2) become increasingly difficult to arouse from PS as the deprivation period progresses; (3) show increased amounts of PS (rebound) in post-deprivation recordings relative to baseline; and (4) compensate for only one-third of the PS deficit incurred during deprivation. Rabbits' response to PS deprivation differs from other mammals in the following ways: (1) the deprivation procedure is truly selective, significantly affecting only amounts of PS and not total sleep time or other sleep stages; (2) the rebound response is restricted to the light phase of the light-dark cycle on the first recovery day; and (3) as indexed by eye movement density, phasic activity during PS is not enhanced during the recovery period. Given that the crucial factor in the PS deprivation-compensation phenomenon is thought to be the deprivation and subsequent enhanced occurrence of phasic events, and considering that events within the oculomotor system have been emphasized in this regard, the results of this investigation suggest the existence of species differences regarding the nature and form of the compensatory response to PS deprivation.

Animals↗
PubMed1986

Circumferential para-aortic masses: computed tomographic observations.

Of 59 patients in whom computed tomography (CT) demonstrated large para-aortic masses engulfing the aorta, lymphoma was responsible in 32 (54%). In 22 (69%) of these 32 patients the mass appeared confluent while in 10 some nodularity could be discerned. Thirty-five of the 59 patients were known to have an underlying malignancy at the time of the CT; in every case the underlying malignancy proved to be responsible for the mass. Amongst 24 patients in whom the CT abnormality was found in the course of initial diagnosis, lymphoma proved to be responsible in 11 (46%), periaortitis in 4 (17%) and various malignancies in 9 (38%). In none of the patients with periaortitis was the aorta displaced from the vertebral body. The combination of such aortic displacement and mesenteric lymphadenopathy is highly characteristic of non-Hodgkin's lymphoma. Knowledge of these results should assist the choice of the appropriate type of biopsy in this situation.

Abdominal Neoplasms↗
PubMed1986

Sleep-wakefulness rhythms in the rabbit.

The characteristics and stability of sleep-wakefulness patterns across consecutive 24-h periods were examined in adult male rabbits implanted for chronic recording of electroencephalographic, eye movement, and nuchal muscle activities. Criteria for stage scoring along with associated scoring reliability are presented. Rabbits slept an average of 11.4 h per day, 25.9% of which was drowsy, 64.5% slow wave sleep, and 9.6% paradoxical sleep. Diurnal differences in amount and type of sleep, consisting of increased wakefulness and decreased paradoxical sleep during the dark phase of the light-dark cycle, were observed. The results are integrated with those of previous sleep studies in this species and phylogenetic implications of variations in the distribution and characteristics of sleep in the rabbit are discussed.

Animals↗
PubMed1986

Abnormal accumulation of sulphated materials in lens tissue of mice with the aphakia mutation.

Sulphated materials were tested for in the eyes of late gestational and postnatal normal mice and mice with the aphakia mutation using Spicer's high iron diamine staining method. Qualitative identification of these materials was attempted with bovine testicular hyaluronidase and nitrous acid digestion methods. The grossly abnormal morphology of the aphakia lens made it necessary to confirm identification of lens-derived tissue by testing for lens crystallins using standard immunohistological methods. As seen in normal mouse lens maturation, accumulated inter- and intracellular sulphated materials were observed in aphakia lens tissue from just before birth through juvenile maturation. Large cyst-like structures consisting of lens-derived tissue were commonly seen in the eyes of young postnatal mutant mice. Sulphated materials formed basal lamina-like structures on many of these lens-derived units, but a well-defined lens capsule never formed. Abnormal fibrillar structures rich in sulphated materials were seen in the intraocular cavity in many older mutant specimens, most of which were largely resistant to both digestion methods. These results indicate that the potential to elaborate sulphated materials qualitatively similar to those seen in normal mouse lens maturation is present in the aphakia mutant, although the mode of accumulation is grossly disturbed.

Animals↗
PubMed1985

Compound effects of bisulphite ion on frog skeletal muscle.

To characterize the structures of the nicotinic cholinoceptors in the frog rectus abdominis muscle, group-selective reagents have been used. Possible modifications of the excitation-contraction coupling have also been studied. The effect of the bisulphite ion on skeletal muscle has been demonstrated earlier at presynaptic and postsynaptic levels. Another report questioned whether these effects were significant to the contractile process in general. The present study shows that bisulphite induced qualitative and quantitative changes in the muscular response to acetylcholine and electrical stimulation. The intervention is likely at the level of excitation-contraction coupling as well as at the previously proposed sites.

Acetylcholine↗