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Biomedical subjects

D Graham

Publications and source records attributed to D Graham.

At least 73 records · Page 4Linked to original sources
PubMed1988

The management of localized abdominal aortic dissections.

Aortic dissections limited to the abdominal aorta occur infrequently. We have identified four cases of abdominal aortic dissection and have reviewed these in combination with 43 previously reported cases to identify factors that influence the prognosis and management of this disease. Abdominal aortic dissections are similar to thoracic dissections in their presentation, with acute shearing pain and systolic hypertension occurring commonly. Although the diagnosis may be made by ultrasonography or CT scanning, angiography is the definitive diagnostic study. Factors found to be associated with high mortality include presentation with acute pain (p less than 0.0003), involvement of visceral vessels (p less than 0.02), and rupture (p less than 0.000002). Chronicity appears to be protective (p less than 0.04), although chronic dissections may present acutely. Although prosthetic replacement of the involved aorta is the treatment of choice in most cases, nonoperative management with regular follow-up can be considered in asymptomatic chronic dissections.

Aged↗
PubMed1988

Health concerns of high school students and teachers' beliefs about student health concerns.

Information about health concerns of adolescents can assist in assessment and treatment of their particular medical problems. Because teachers are important figures in the lives of young people, their beliefs about student health concerns are often solicited. A survey to assess adolescent health concerns and teachers' beliefs about student health concerns was conducted in two urban high schools on a sample of 831 students and 146 teachers. An assessment of 22 health concerns among the students revealed that a moderate level of concern existed on virtually every issue (the mean percentage "very concerned" was 55%), with black students and girls reporting more concern about many topics. In contrast, teachers significantly underestimated the level of concern of the students by an average of 13%, consistently having inaccurate beliefs about the types and level of student concerns. Students are concerned about health issues and are in need of health education and counseling in these areas. Teachers are not always aware of the level and types of student health concerns and may not be good sources of information about adolescent health.

Adolescent↗
PubMed1987

An evaluation of a structured case record in a paediatric department.

Two hundred and thirty-four paediatric medical records from August 1985 and 257 from August 1986, were evaluated and compared by criteria audit in order to assess the effects of the introduction of a structured admission form. The presence or absence of predetermined items of clinical relevance were recorded. A statistically significant improvement in the recording of 12 of 23 key items occurred following the introduction of a structured format. However, two of these items were recorded less frequently in the new notes. Changing working hours for house officers and an increase in overseas graduates had no significant influence on the results. Structured case records can improve information gathering, but careful design and reevaluation are important.

Child↗
PubMed1987

cDNA sequences of two apolipoproteins from lamprey.

The messages for two small but abundant apolipoproteins found in lamprey blood plasma were cloned with the aid of oligonucleotide probes based on amino-terminal sequences. In both cases, numerous clones were identified in a lamprey liver cDNA library, consistent with the great abundance of these proteins in lamprey blood. One of the cDNAs (LAL1) has a coding region of 105 amino acids that corresponds to a 21-residue signal peptide, a putative 8-residue propeptide, and the 76-residue mature protein found in blood. The other cDNA (LAL2) codes for a total of 191 residues, the first 23 of which constitute a signal peptide. The two proteins, which occur in the "high-density lipoprotein fraction" of ultracentrifuged plasma, have amino acid compositions similar to those of apolipoproteins found in mammalian blood; computer analysis indicates that the sequences are largely helix-permissive. When the sequences were searched against an amino acid sequence data base, rat apolipoprotein IV was the best matching candidate in both cases. Although a reasonable alignment can be made with that sequence and LAL1, definitive assignment of the two lamprey proteins to typical mammalian classes cannot be made at this point.

Amino Acid Sequence↗
PubMed1987

Effect of chronic treatment with selective monoamine oxidase inhibitors and specific 5-hydroxytryptamine uptake inhibitors on [3H]paroxetine binding to cerebral cortical membranes of the rat.

[3H]Paroxetine is a highly selective ligand for the 5-hydroxytryptamine transporter complex and the specific binding of this ligand to membrane fractions from cerebral cortex or hippocampus was studied in rats treated with specific inhibitors of the uptake of 5-hydroxytryptamine and monoamine oxidase inhibitors. The Kd and Bmax of the binding of [3H]paroxetine to cerebral cortical membranes of the rat was unaffected, compared to sham controls, by either acute or chronic administration with citalopram or chlorimipramine. Also, chronic treatment with chlorimipramine did not alter the parameters of the binding of [3H]paroxetine to hippocampal membranes from the rat compared to sham controls. Furthermore, chronic and acute treatments with clorgyline or deprenyl did not produce any significant changes in the Kd and Bmax of the binding of [3H]paroxetine to cerebral cortical membranes in the rat. These findings on the binding of [3H]paroxetine are discussed in light of previous equivocal results on the plasticity of neuronal binding sites for [3H]imipramine after various pharmacological treatments.

Animals↗
PubMed1987

[3H]tryptamine binding sites of rat cerebral cortex: pharmacological profile and plasticity.

Equilibrium saturation analysis of the binding of [3H]tryptamine to membranes from the cerebral cortex of the rat at 0 degrees C indicated that [3H]tryptamine bound to a single class of high affinity binding sites (Kd = 1.29 +/- 0.13 nM). The binding of [3H]tryptamine was potently inhibited by tryptamine itself, beta-carboline, tetrahydro-beta-carboline and several beta-phenylethylamine derivatives. Structure-activity relationships of the beta-phenylethylamines tested showed that substitutions in para-position were the most potent with the following rank order of potency H less than OH less than Cl less than OCH3. Although chronic treatment with parachlorophenylalanine did not affect the parameters of the binding of [3H]tryptamine to cerebral cortical membranes of the rat, chronic treatment with clorgyline and deprenyl resulted in a 49% decrease in the density of binding sites for [3H]tryptamine, with no change in Kd. This modulation of the binding of [3H]tryptamine lends support to the proposal that binding sites for [3H]tryptamine could represent a specific class of receptors in the CNS. As such, the structure-activity relationships revealed within and between the various families of compounds tested provides useful information for the development of new chemical tools as potential agonists and/or antagonists at these sites.

Animals↗
PubMed1987

Biparietal diameter growth in uncomplicated twin gestation.

Ninety-six fetuses of uncomplicated concordant twin pregnancies were monitored by ultrasonic cephalometry from 13 to 38 weeks gestation. The biparietal diameter (BPD) growth of 96 twin fetuses was then compared to a sample of 299 uncomplicated, appropriate-for-gestational-age singleton pregnancies. Regression analysis applied to these measurements of BPD on twin and singleton pregnancies showed no significant difference in biparietal diameter between uncomplicated singleton and twin pregnancies. It is concluded that charts derived from singleton pregnancies may be reliably used for estimation of gestational age of twins.

Cephalometry↗
PubMed1987

Significance of ultrasound measurements of the head of the breech fetus.

Ultrasound measurements of head shape and size in 451 fetuses presenting as a breech were compared to those obtained in 1,880 fetuses presenting as a cephalic between 15 and 40 weeks' gestation. No statistically significant differences were found for the biparietal diameter (BPD), head circumference (HC), or cephalic index (CI) measurements between the two groups in uncomplicated pregnancies. The mean values for the CI were found to be lower for breech presenting fetuses in complicated pregnancies, indicating a trend for these fetuses to have a more dolichocephalic head shape.

Breech Presentation↗
PubMed1987

C-reactive protein is involved in natural killer cell-mediated lysis but does not mediate effector-target cell recognition.

Anti-CRP and complement treatment of human peripheral blood lymphocytes significantly reduces natural killer (NK) cell-mediated cytotoxicity to K562 target cells as well as to MOLT-4 target cells. Although not all activity is eliminated by treatment of effector cells with antibody and complement, the reduction of NK function indicates that C-reactive protein (CRP) is present on a significant proportion of NK cells. Higher concentrations of anti-CRP or anti-CRP F(ab')2 fragments also reduce NK function; this suggests that CRP is not only present on these effector cells but may also play a role in NK-mediated killing. We initially suspected that CRP-ligand interactions might be involved in effector-target cell recognition. Several lines of evidence suggest that this is not the case. While F(ab')2 anti-CRP will block NK function, Fab anti-CRP will not, suggesting that the NK response is not impaired when surface CRP (S-CRP) is blocked but is only inhibited when the S-CRP is cross-linked and modulated. Neither CRP-C polysaccharide complexes (CRP-CPS) nor concentrations of CPS ranging from 0.1 microgram/ml to 200 micrograms/ml have any effect on NK cell-mediated killing. Treatment of target cells with a ligand for CRP or CRP prior to co-culture with NK effectors does not augment NK function. Single cell assays clearly demonstrate that high concentrations of anti-CRP have no effect on the formation of effector-target cell conjugates. Although these concentrations of anti-CRP do not block effector-target cell conjugation in the single cell assay, they do block the killing of conjugated target cells. In total, this evidence strongly suggests that although CRP appears to be involved in NK-mediated killing, it is not involved in effector-target cell-mediated recognition.

Antibodies↗
PubMed1987

Recombinant tumor necrosis factor causes activation of human granulocytes.

We have tested the hypothesis that tumor necrosis factor (TNF), by binding to and activating granulocytes, may contribute to the pathogenesis of gram-negative sepsis and the adult respiratory distress syndrome (ARDS). Buffy coat granulocytes incubated with as little as 0.5 ng/mL of recombinant TNF (rTNF) showed a dose-related increase in nitroblue tetrazolium dye reduction, in granulocyte polarization, in superoxide anion release, and in visually apparent aggregation. Purified lipopolysaccharide (1 microgram/mL) caused polymorphonuclear (PMN) aggregation and activation that was neutralized by polymyxin B. The release of superoxide was augmented by preincubation of the PMNs with gamma-interferon. The effect of TNF was neutralized by TNF-specific murine monoclonal antibodies but not by polymyxin B. Scatchard analysis of 125I-rTNF binding to granulocytes revealed about 1,200 receptors per cell with a Kd of 4.9 X 10(-10) mol/L. These results suggest that the release of TNF by mononuclear phagocytes contributes to granulocyte activation and aggregation during inflammation.

Glycoproteins↗
PubMed1986

Solubilization and characterization of the 5-hydroxytryptamine transporter complex from rat cerebral cortical membranes.

The 5-hydroxytryptamine transporter complex from rat cerebral cortical membranes was solubilized with digitonin. The affinity of the solubilized transporter complex for [3H]paroxetine, a very selective and potent inhibitor of 5-hydroxytryptamine uptake, was not affected and remained unchanged when compared with the parent membrane preparation. The solubilization yield of membrane-bound [3H]paroxetine binding sites was 42%. The pharmacological profile of the solubilized transporter complex was similar to that of the intact transporter in membranes of the cerebral cortex, with the exception of tryptamine, which exhibited a 10-fold loss in potency to inhibit [3H]paroxetine binding to the solubilized transporter when compared to membranes. The Stokes radius determined by gel filtration was 7.6 nm. This successful solubilization of the neuronal 5-hydroxytryptamine transporter complex is the starting point for purification of this macromolecular moiety.

Animals↗
PubMed1986

Cysts in pregnancy discovered by sonography.

The incidence of cysts in pregnancy was established with ultrasound. In 3,330 pregnant patients who underwent sonography, 38 adnexal cystic lesions (1.14%) were found. All but two cysts were discovered before 16 weeks. Follow-up showed that the majority of the cystic lesions resolved spontaneously; these were presumed to represent corpus luteum cysts. Five patients underwent surgery because of persistent cystic lesions; a mucinous cystadenoma, a benign cystic teratoma, a paraovarian cyst, an inclusion cyst, and a tuboovarian abscess were found. Septations and echogenic material were seen within the cystic teratoma and the tuboovarian abscess but the sonographic features of the other operated lesions were identical to those seen in the corpus luteum cysts.

Abscess↗
PubMed1986

Relationship of placental grade to fetal pulmonary maturity and respiratory distress syndrome.

Real-time sonographic placental grading was performed on 215 patients who had amniocentesis for determination of fetal pulmonary maturity between 26 and 42 weeks of gestation. The results of this placental grading were correlated with clinical gestational age and fetal pulmonary maturity, assessed by lecithin-sphingomyelin ratio, phosphatidylglycerol, and the subsequent presence or absence of respiratory distress syndrome. This study showed a statistically significant correlation of placental grade with gestational age, pulmonary maturity, and respiratory distress. Grade 3 placentas were seen in 20% of the cases studied, and in every instance was associated with an absence of subsequent neonatal respiratory distress. Placental grade appeared to be an accurate predictor of fetal pulmonary maturity in the population studied.

Amniocentesis↗
PubMed1986

Treatment of benign chronic gastric ulcer with ranitidine. A randomized, double-blind, and placebo-controlled six week trial.

A randomized, multicenter, double-blind, placebo-controlled study was conducted to determine whether ranitidine 150 mg b.i.d. for 6 weeks would expedite endoscopic healing or relief of symptoms in patients with benign gastric ulcer. Of 203 patients enrolled, 101 received ranitidine and 102 received placebo. Endoscopic evaluations were conducted at baseline and at 2 and 6 weeks. At 6 weeks 68% of the patients treated with ranitidine had healed compared with 53% in the placebo group (p = 0.02). In those patients who had not healed by 6 weeks, ranitidine provided greater relief from pain than placebo. More patients in the placebo group dropped out of the study because of worsening symptoms (13 versus 4, p = 0.04). No differences in laboratory abnormalities or incidence of adverse events were detected between the two study groups. These results indicate that ranitidine 150 mg b.i.d. is superior to placebo in the treatment of benign gastric ulcer.

Adult↗
PubMed1986

Evidence that the 'active centre' of the herpes simplex virus thymidine kinase involves an interaction between three distinct regions of the polypeptide.

The nucleotide sequence of the coding region of the thymidine kinase gene from each of three mutant strains of herpes simplex virus type 1 and from the parental strain, SC16, has been determined. The mutants were known to express thymidine kinase enzymes with distinct substrate binding properties. Consideration of the lesions in the genes responsible for these altered biochemical properties. Consideration of the lesions in the genes responsible for these altered biochemical properties has led us to postulate a preliminary model for the active centre of the enzyme, involving the cooperation of three distinct regions of the polypeptide.

Adenosine Triphosphate↗