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Biomedical subjects

M Lipton

Publications and source records attributed to M Lipton.

At least 19 recordsLinked to original sources
PubMed2006

The importance of children's illness beliefs: the Children's Illness Perception Questionnaire (CIPQ) as a reliable assessment tool for eczema and asthma.

A lack of information about disease in children can lead to erroneous views such as children believing that hospital admittance or the presence of a disease is a punishment for a perceived wrong. There has thus far been no standard tool available to measure children's illness conceptualizations from a Leventhalian framework. Three groups of children with eczema, asthma and eczema and asthma between the ages of 7 and 12 years of age were recruited. Children were given the Children's Illness Perception Questionnaire (CIPQ), a 26-item instrument adapted from the Illness Perception Questionnaire for adults. A Kuder - Richardson 20 test of reliability for dichotomous data was performed allowing an estimate of the internal consistency of the measurement scales. It can be seen that, for all three illness groups, internal consistency is acceptable for the timeline and consequences scale. The cure/control scale, however, was not internally consistent for any illness group. As health professionals, we need to develop the means to further understand how paediatric illness beliefs relate to specific disease types, age and psychosocial factors and the utility of this instrument is discussed within this context.

Asthma↗
PubMed2005

A randomized controlled trial of laser treatment among hirsute women with polycystic ovary syndrome.

BACKGROUND: Facial hirsutism is one of the characteristic features of polycystic ovary syndrome (PCOS), and this can lead to high levels of depression and anxiety. OBJECTIVES: To evaluate the impact of laser treatment on the severity of facial hirsutism and on psychological morbidity in women with PCOS. METHODS: A randomized controlled trial of five high-fluence treatments (intervention) vs. five low-fluence treatments (control) was performed over 6 months in a National Health Service teaching hospital. Subjects were 88 women with facial hirsutism due to PCOS recruited from hospital outpatient clinics and a patient support group in 2001-2002. The main outcomes were self-reported severity of facial hair (measured on a scale of 1-10), depression, anxiety (measured on the Hospital Anxiety and Depression Scale) and quality of life (measured on the WHOQOL-BREF). RESULTS: Self-reported severity of facial hair in the intervention group (n = 51) fell from 7.3 to 3.6 over the 6-month study period; for the control group (n = 37) the corresponding scores were 7.1 and 6.1. The change was significantly greater in the intervention group [ancova F((1,83)) = 24.5, P < 0.05]. Self-reported time spent on hair removal declined from 112 to 21 min per week in the intervention group and from 92 to 56 min in the control group [F((1,80)) = 10.2, P </= 0.05]. Mean depression scores fell from 6.7 to 3.6 in the intervention group, compared with 6.1 to 5.4 in the control group [F((1,83)) = 14.7, P < 0.05]. A similar change was seen for mean anxiety scores: intervention 11.1 to 8.2, control 9.6 to 9.3 [F((1,84)) = 17.8, P < 0.05]. Psychological quality of life also improved more in the intervention group, from 49.6 to 61.2 vs. 50.1 to 51.5 in the control group [F((1,84)) = 10.9, P < 0.05]. CONCLUSIONS: Laser treatment appeared to reduce the severity of facial hair and time spent on hair removal as well as alleviating depression and anxiety in women with PCOS. These findings suggest that ways of making this method of hair removal more widely available to women with facial hirsutism should be considered.

Adult↗
PubMed2001

Challenges to meet: food and nutrition security in the new millennium.

Before about 1750 there was no substantial secular fall in protein-energy malnutrition (PEM) over large areas, nor reason to expect it. We have since learned that sufficient economic advance (poverty reduction) plus scientific advance (in medicine and food production) are achievable to eliminate mass PEM. The two advances are linked via increased demand for labour, and hence wages and employment, for those formerly too poor to afford adequate food. The extra employment income arises first from smallholder and employee food production, and later, as labour is released, from a wide range of specialised, increasingly non-farm, production, with employment income traded for food. This process eliminated mass hunger in Europe in 1750-1960. Only by 1975 had PEM in the developing world retreated to (very high) 1936-8 levels, but it fell sharply in Asia and Latin America in 1975-1990, due to unprecedented growth in staples yields, smallholder and farm employment income, and hence the poor's purchasing power over food. However, since 1990, poverty reduction has slowed (before reaching most of Africa), alongside much slower-staples yield growth, increasing water shortages, and big shifts of grain and land from man to farm animals. These trends prefigure declining progress against PEM in coming decades, unless there is renewed, employment-intensive food-staples-yield growth. That process requires reorienting crop biotechnology and water science towards the needs of small tropical farmers and their staple food crops, and shifting land towards them. Mass PEM is indeed largely due to inadequate 'food entitlements' by the hungry, but will not be remedied without growth in their employment, based on further advances in food-staples yields per unit land and water. Recent evidence suggests that early PEM may increase lifelong risks of infection and/or degenerative disease. This factor would increase the 'squeeze' on health resources in low-income countries, between the diseases of poverty and those of old age. That situation increases the need to readdress PEM by renewed progress in food production and land distribution.

Biotechnology↗
PubMed1998

Sinus histiocytosis with massive lymphadenopathy involving the orbit: reversal of compressive optic neuropathy after chemotherapy.

A 38-year-old woman from Antigua had compressive optic neuropathy of the right eye caused by orbital involvement with sinus histiocytosis. There was also nasal sinus involvement and massive cervical lymphadenopathy resulting in radiographic compression of the airway and carotid sheath. Because of the compressive optic neuropathy and threat to the airway and carotid perfusion, the patient underwent a 6-month chemotherapeutic regimen of cyclophosphamide, vincristine, and prednisone. After chemotherapy, the visual dysfunction resolved in correlation with diminution of the orbital mass, and marked regression of the cervical lymphadenopathy. This case demonstrates the potential efficacy of chemotherapy in the treatment of compressive optic neuropathy in cases of orbital sinus histiocytosis with massive lymphadenopathy.

Adult↗
PubMed1994

The rational design of highly stable, amphiphilic helical peptides.

A computer algorithm was devised for the evaluation of helical stability of potentially amphiphilic peptide sequences of specified length containing a set number of leucines in the hydrophobic region. All possible combinations of Glu, Lys and Gln in the hydrophilic region are rated using a set of empirical rules for salt bridge formation in alpha-helices, and the sequences which rate the highest are displayed. The rules for salt bridge formation were largely derived from published studies on the effects of salt bridges on helical stability. The algorithm was tested by redesigning a known amphiphilic alpha-helical peptide, alpha 1B or 1, which has been shown to aggregate into four-helix bundles. Comparison of the circular dichroism spectra of two peptides, 2 and 3, to 1 demonstrated that the redesigned peptide with the highest priority score from the algorithm, 2, was more helical when aggregated and slightly more helical as a monomer, whereas the peptide with the low priority score, 3, was somewhat less helical when aggregated and much less helical when monomeric. These results support the design of the algorithm, although conclusions based on aggregation data are complicated by the importance of interhelix contacts in the bundle. Further studies are underway to examine the reliability of the algorithm's predictions regarding the design of other helical peptides.

Algorithms↗
PubMed1993

Ultrasonic backscatter system for automated on-line endocardial boundary detection: evaluation by ultrafast computed tomography.

OBJECTIVES: The purpose of this study was to evaluate the accuracy of the recently developed echocardiographic on-line endocardial border detection system using ultrafast computed tomography, an independent and proved tomographic imaging modality. BACKGROUND: The automated system for on-line endocardial border detection identifies the blood-tissue interface by acoustic quantification of the ultrasonic backscatter signal. METHODS: Eighteen subjects were screened by conventional echocardiography and acoustic quantification. Ten of these, with high quality echocardiographic images, were also examined by ultrafast computed tomography. Comparable image planes at the midpapillary level were analyzed. Measurements of left ventricular cavity area were compared at end-diastole and end-systole and time course analyses of cavity area during the cardiac cycle were performed. RESULTS: There was good correlation between values for left ventricular end-diastolic area (r = 0.99), end-systolic area (r = 0.93) and fractional area change (r = 0.91) using the two methods. The on-line backscatter system underestimated end-diastolic area (p < 0.001), but the negative bias was small (-1.6 cm2) and the 95% confidence intervals were narrow (-3.6 cm2 to +0.4 cm2). In contrast, the backscatter system overestimated end-systolic area (p < 0.02); the positive bias for this variable was also small (+2.6 cm2) but the confidence intervals were relatively wide (+7.9 to -2.8 cm2). The negative bias of backscatter values for cavity area was fairly constant during diastole and early systole (range -5% to -10%), but during the second half of systole, backscatter values increased progressively relative to computed tomographic values. Real time values for fractional area change measured by the backscatter system were 13% smaller than those determined by ultrafast computed tomography (p < 0.001), with wide confidence intervals (+3% to -30%). Absolute peak rates of area change during systole and diastole were lower by 39% (p < 0.001) and 41% (p < 0.01), respectively, using the on-line ultrasonic backscatter system. Time course analyses revealed the errors to be consistent with cardiac cycle-dependent alterations in gain sensitivity of the ultrasonic backscatter system. CONCLUSIONS: The ultrasonic backscatter system is associated with cyclic cavity area measurement errors that need to be addressed if its early promise for on-line assessment of ventricular function is to be fulfilled. Incorporation of an electrocardiographically triggered time-varying gain control may improve accuracy for on-line analysis of ventricular performance.

Echocardiography↗
PubMed1991

Cytosine arabinoside (ara-C) and cis-dichlorodiammineplatinum II (cisplatin) alone and in combination: effects on acute myeloblastic leukemia blast cells in culture and in vivo.

Cytosine arabinoside (ara-C) and cis-dichlorodiammineplatinum II (cisplatin) are lethal to mammalian cells by very different mechanisms; however, they share interactions with the biology of blast cells in acute myelogeneous leukemia (AML). Both agents are more toxic to AML blasts in suspension than when a clonogenic assay in methyl cellulose is used; both agents are more toxic in suspension in the presence of rG-CSF than with rGM-CSF. Accordingly, preclinical tests were undertaken of cisplatin and ara-C in combination. At the same time, a phase I/II clinical trial of the combination was conducted, using AML patients refractory to treatment or in relapse. In the laboratory, blasts from eight AML patients were tested against each agent singly and in combination. The observed survival values for the mixture were compared with those predicted by assuming either an additive effect or a more general effect that allows synergism or antagonism. Blasts from two patients were tested with this design in the presence of rG-CSF or rGM-CSF. In most instances the toxic effects of ara-C and cisplatin were additive. Evidence of synergism was seen in blasts from three patients.

Adolescent↗
PubMed1988

Sequelae of thrombotic or hemorrhagic complications following L-asparaginase therapy for childhood lymphoblastic leukemia.

Thirty-four cases of childhood lymphoblastic leukemia that were complicated by CNS and peripheral thrombosis or hemorrhage associated with L-asparaginase (L-asp) therapy were reviewed to determine the effect of the events on the subsequent clinical status. There was no predilection for any site in the CNS cases; all but one of the peripheral events occurred in the lower extremities. The median time for 28 CNS and eight peripheral events from the beginning of L-asp therapy was 17 and 16 days, respectively. One patient died as a result of the CNS event. Twenty-six patients were surviving with a median follow-up of 27 months at the close of the study. Of the patients with peripheral thromboses, only the patient with a dorsal pedal artery occlusion had a significant problem (autoamputation of a toe). Although eight patients received L-asp subsequently without recurrence of the complication, two had transient neurological deterioration associated with the repeat administration of L-asp. Twenty-two patients received CNS prophylaxis consisting of intrathecal methotrexate, CNS radiation, or both, following the CNS event without deterioration. In general, clinical status was not compromised after thrombotic or hemorrhagic events. Although most patients had gross recovery of their neurological impairment, detailed neurological and neuropsychological testing is needed to elucidate possible defects.

Adolescent↗
PubMed1984

[Imaging of blood flow-dependent curve parameters in the course of sequential computed tomography of the kidneys following intravenous injection of a contrast bolus].

Since the introduction of fast CT scanners with short scanning times the early density changes observed during the first transit of a contrast bolus can be clearly demonstrated and quantified. A theoretical curve can be fit to the CT data describing the density changes in the kidney according to the indicator dilution principle. A curve parameter can be obtained which characterizes the shape of the curve. Then an image can be calculated which reflects the selected curve parameter rather than tissue densities. Such images have been termed "functional images". Using this type of imaging we were able to demonstrate acute changes in renal perfusion.

Animals↗
PubMed1983

The interaction of cAMP with modeled bull sperm.

Demembranated and membrane disrupted bull sperm models exhibit an increase in motility when exposed to cAMP. Tritium-labeled cAMP was used to locate the initial site of action of cAMP in the modeled sperm preparations. cAMP did not bind selectively to the modeled cells, and the presence or absence of plasma membrane fragments on the models did not significantly alter this result. When suspension medium taken from modeled sperm preparations was subjected to gel filtration on Sephadex G25-150 columns, cAMP bound to a high molecular weight component that eluted with the void volume. The responsible binding factor is a soluble component that is released when the plasma membranes of the sperm are disrupted during the modeling procedure. To test the importance of the cAMP binding factor, modeled sperm were centrifuged, the supernatant solution was decanted, and the cells were resuspended in fresh medium. After this treatment the cells could be restored to motility with Mg-ATP but no longer exhibited a response to cAMP. Furthermore, addition of cAMP binding factor isolated by gel filtration partially restored the response of these sperm to cAMP. Investigation of the properties of the cAMP-binding factor have confirmed that it is specific for cAMP, with a much lower affinity for AMP and cGMP. In the presence of a large excess of unlabeled cAMP the labeled complex has a half-life of approximately 1 hour. Our results indicate that the action of cAMP on the motility of modeled sperm is mediated by its attachment to a high molecular weight, soluble component of the cell cytoplasm.

Animals↗