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Biomedical subjects

A Dick

Publications and source records attributed to A Dick.

At least 55 records · Page 3Linked to original sources
PubMed1995

Molecular cloning and DNA sequence analysis of pepL, a leucyl aminopeptidase gene from Lactobacillus delbrueckii subsp. lactis DSM7290.

A genomic library of Lactobacillus delbrueckii subsp. lactis DSM7290 DNA fragments from a Sau3A partial digestion in the low-copy-number vector pLG339, was used to screen Escherichia coli for the presence of peptidases. Using the chromogenic substrate leucine-beta-naphthylamide (Leu-NH-Nap) and E. coli strain CM89 lacking the corresponding enzyme activity in an enzymic plate assay, allowed the isolation of two peptidase genes; the newly described pepL and the recently cloned and sequenced pepN. Clones could be distinguished not only by the restriction pattern of isolated plasmids but also by the rate and intensity of their colour reaction with Leu-NH-Nap. Three out of five clones were identified to express the Lactobacillus pepN gene; the others were shown to express a second aminopeptidase gene, designated pepL. This gene, together with 200 bp upstream of the proposed AUG initiation codon, was further subcloned and sequenced. The corresponding open reading frame of 897 nucleotides is predicted to encode a protein of 299 amino acids (34,541 Da). Searching the EMBL database revealed similarity to the prolinase of Lactobacillus helveticus (45.8% identity), to the iminopeptidases of Lb. delbrueckii subsp. lactis and Lb. delbrueckii subsp. bulgaricus (25.5%), and to the Bacillus coagulans prolinase (21.5%). Minor similarities were detected for hydrolytic enzymes with serine active sites. The product encoded by the pepL gene was functional but could not be visualized on Coomassie-blue-stained polyacrylamide gels. High level expression of peptidase L in E. coli was achieved by placing the gene under the control of the T7 promoter.

Amino Acid Sequence↗
PubMed1995

Effects of adrenaline and hyaluronidase on plasma concentrations of lignocaine and bupivacaine after peribulbar anaesthesia.

We have measured peak plasma concentrations of lignocaine and bupivacaine after dual injection peribulbar block and investigated the influence of adrenaline and hyaluronidase. Twenty-four patients were allocated randomly to one of four groups: (I) local anaesthetic alone (lignocaine 10 mg ml-1-bupivacaine 3.75 mg ml-1); (II) local anaesthetic with adrenaline (5 micrograms ml-1); (III) local anaesthetic with hyaluronidase (75 iu ml-1); or (IV) local anaesthetic with adrenaline and hyaluronidase. Venous plasma concentrations of lignocaine and bupivacaine were measured in 24 patients using gas liquid chromatography before and at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 180, 300 and 540 min after completion of the peribulbar injections. Main outcome measures were analysed using two-way analysis of variance. All patients, with one exception, received 10 ml of the local anaesthetic mixture. Overall peak plasma concentrations varied from 230 to 1910 micrograms ml-1 for lignocaine and from 160 to 1090 micrograms ml-1 for bupivacaine. Adrenaline significantly reduced peak plasma concentrations of lignocaine to 57% (P = 0.001) and bupivacaine to 61% (P = 0.004) compared with the nonadrenaline groups. Hyaluronidase had no significant effect on peak plasma concentrations of lignocaine and bupivacaine, which were 90% (P = 0.34) and 100% (P = 0.84) of the non-hyaluronidase groups. The area under the plasma concentration-time curves to 300 min (AUC300) behaved similarly. There was a reduction in AUC300 for lignocaine (P = 0.005) and bupivacaine (P = 0.011) in the adrenaline groups compared with the non-adrenaline groups, in contrast with no significant effects of hyaluronidase on AUC300 for lignocaine (P = 0.14) or bupivacaine (P = 0.53) compared with the non-hyaluronidase groups.

Adjuvants, Pharmaceutic↗
PubMed1993

Retinal antigen specific lymphocytes, TCR-gamma delta T cells and CD5+ B cells cultured from the vitreous in acute sympathetic ophthalmitis.

CD5+ B lymphocytes and TCR gamma-delta T lymphocytes, phenotypes implicated in the pathogenesis of autoimmune disease, were isolated from the vitreous in a case of acute sympathetic ophthalmitis. These cells were obtained using a method which allows the selective maintainance in vitro of in vivo activated T lymphocytes. Dual colour flow cytometry showed that after 3 days culture in IL-2 containing medium 61% of cells were CD5/CD19 + ve and 41% CD3/TCR gamma delta + ve. Of the total CD3 + ve population, 15% were gamma/delta negative. These cells formed a population which also responded in a proliferation assay to retinal antigens. Histologically the eye showed a marked mononuclear cell infiltration of the retina, ciliary body and choroid. Granulomatous lesions within the choroid contained lymphocytes, plasma cells and multinucleate giant cells. Immunocytochemistry showed lymphocyte populations to be predominantly CD2 + ve CD3 + ve T lymphocytes of the CD4 sub-set. Distribution of monocytes/macrophages throughout the lesions and restriction of B-lymphocytes to granulomata were all consistent with a DTH type reaction. Despite immunosuppressive therapy, the expression of activation antigens HLA-DR and ICAM-1 on infiltrating and resident ocular tissue cells was high, although IL-2 receptor (CD25) expression was virtually absent. Flow cytometric analysis of peripheral blood cells prior to treatment with Cyclosporin-A showed systemic activation of lymphocytes, with high levels of HLA-DR and CD25 expression and a raised CD4/CD8 ratio.

Antigens↗
PubMed1992

Experimental autoimmune uveoretinitis: a model system for immunointervention: a review.

Experimental autoimmune uveoretinitis (EAU) is a useful model of human posterior uveitis and as such, permits the analysis of strategies for immuno-intervention. Modulation of the autoimmune response may be attempted at the stages of induction of EAU, during homing of autoreactive lymphocytes to the target organ, the retina, or during the effector stage of the disease. This paper presents a brief overview of current immuno-therapeutic modalities and assesses the usefulness for extrapolation to human disease.

Animals↗
PubMed1991

Topographical and topological organization of the thalamocortical projection to the striate and prestriate cortex in the marmoset (Callithrix jacchus).

In eleven hemispheres of nine marmoset monkeys (Callithrix jacchus), we have investigated the thalamo-cortical organization of the projections from the pulvinar to the striate and prestriate cortex. In each experiment, single or multiple injections of various retrograde fluorescent tracers were injected into adjacent regions or areas. In two experiments, horseradish peroxidase (HRP) was injected into the lateral geniculate nucleus (LGN) and the lateral pulvinar, respectively. The results show that the thalamo-cortical projection from LGN to striate cortex and from pulvinar to the prestriate cortex are similarly organized, but the geniculo-striate projection is more precise than the pulvinar-prestriate projection. The pulvinar-prestriate projection is topographically organized and preserves topological neighbourhood relations. Projection zones to the various visual areas are concentrically wrapped around each other. The projection zone to area 18 constitutes a central core region. It begins ventro-laterally in PuL where the pulvinar is in contact with the LGN. This contact zone we called the hilus region of the pulvinar. The area 18-projection zone stretches as a central cone into the posterior pulvinar through PuL and into PuM. It is surrounded by the projection zone to the posterior belt of area 19 and this in turn is surrounded by the projection zone to the anterior belt of area 19. The projection zones to area 19 are then surrounded medially and dorsally by zones projection to the temporal and parietal association cortex, respectively. The projection zone to area MT is located medio-ventrally in the posterior pulvinar (PuIP and surrounding nuclei) and coincides with a densely myelinated region. Area 17 also receives input from the pulvinar but probably predominantly in the region of the central visual field. The pulvinar zone projecting to area 17 is located ventrolaterally from the central core region projecting to area 18 and is contiguous laterally with the LGN. If the positions of the vertical and the horizontal meridian in the pulvinar correspond to those in the respective cortical projection zones, a second order visual field representation such as found in area 18, with the horizontal meridian split at an eccentricity of about 7-10 degrees, can also be recognized in the pulvinar.

Acetylcholinesterase↗
PubMed1991

The local domain for divergence of subcortical afferents to the striate and extrastriate visual cortex in the common marmoset (Callithrix jacchus): a multiple labelling study.

In the common marmoset (Callithrix jacchus), the cortical projection from the pulvinar and other diencephalic structures into the striate and prestriate cortex was investigated with various fluorescent retrograde tracers. Single cortical injections as well as multiple injections at distances of 1-2 mm with one tracer into an extended but coherent cortical region were applied. Fields with multiple injections were placed so that they touched each other (minimal distances 2 to 3 mm). Retrogradely labelled cells in the LGN and/or the pulvinar were arranged in coherent columns, volumes or slabs, but cell volumes resulting from neighbouring cortical injections overlapped at their border (for details of the thalamo-cortical topography see the companion paper Dick et al. (1991]. Double labelled cells (dl) were only found in the zones of overlap of the cell volumes labelled by the respective tracers. The relative number of dl-cells in these overlap zones was 6.2 +/- 3.1%. The dl-frequency was the same in the various nuclei of the pulvinar and the LGN. In the main layers of LGN, dl-cells were found only in the overlap zone of two injection fields into area 17, but a few dl-cells were found in interlaminar cells after injections into area 17 and 18. Maximal cortical distances between injection fields which produced dl in the pulvinar, were 3 to exceptionally 4 mm but dl was highest at injection distances less than or equal to 2.5 mm and decreased sharply at wider distances. Such overlap zones were concerned with identical or overlapping regions of visual field representation in the cortex and probably also in the pulvinar. Although in individual experiments up to four different tracers were injected into different striate/prestriate regions, often embracing the same visual field representation, individual cells in the pulvinar showed dl from maximally only two tracers injected into neighbouring cortical regions. We conclude that dl in the posterior thalamic projection nuclei is determined essentially by cortical distance and thus reflects the local domain of branching of thalamo-cortical afferents. Pruning of such branches during development may further restrict bifurcating axons to identical visual field representations, but representation of identical visual field regions in different visual areas is not, per se, a sufficient condition for dl. It is not found if such regions are further apart from each other than the typical local domain of 2-3 mm, exceptionally up to 4 mm in one experiment after injections into area 17 and MT.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1989

Abnormal left ventricular-left atrial posterior wall contour: a new two-dimensional echocardiographic sign in constrictive pericarditis.

We measured the angle P formed by the junction of the left ventricular and left atrial posterior walls, and also the distances from the ultrasound transducer to the left ventricular posterior wall and left atrial posterior wall (DV and DA), respectively, in the parasternal long-axis two-dimensional echocardiographic view. We studied 23 normal adults and four patient groups with conditions commonly associated with left atrial dilatation: mitral regurgitation (14), mitral stenosis (16), hypertrophic cardiomyopathy (13), and constrictive pericarditis (7). Statistically significant differences were found between the constrictive pericarditis group and each of the other groups. Angle P was less than 150 degrees in 0 of 23 normal individuals, in 0 of 14 with mitral regurgitation, in 1 of 16 with mitral stenosis, in 0 of 13 with hypertrophic cardiomyopathy, and in five of seven with constrictive pericarditis. DA minus DV exceeded 20 mm in 0 of 23 normal individuals, one of four with mitral regurgitation, in 6 of 16 with mitral stenosis, in 0 of 13 with hypertrophic cardiomyopathy, and in five of seven patients with constrictive pericarditis; We conclude that angle P greater than 150 degrees suggests constrictive pericarditis; DA minus DV greater than 20 mm suggests constrictive pericarditis if mitral stenosis can be excluded.

Echocardiography↗
PubMed1989

Large pericardial effusion after cardiac surgery: role of echocardiography in diagnosis and management.

We performed M-mode and two-dimensional (2-D) echocardiograms prospectively in 140 patients an average of eight days after open heart surgery. Large pericardial effusions occurred in 13 patients; three had complete circumcardiac pericardial effusion, four had local anterior adhesions, five had extensive anterior adhesions (posterior loculated effusion), and one had a large loculated pericardial effusion contiguous to the right atrium. In five patients with tamponade, the effusion was drained, with immediate reversal of symptoms and signs of tamponade. In the other eight patients, who had no deterioration in cardiovascular status, the effusion was not drained; instead, these patients were treated medically with indomethacin and observed with serial echocardiograms, and the effusions eventually disappeared. The most consistent echocardiographic differences between the five patients with and the eight patients without tamponade were that patients with tamponade had larger posterior pericardial effusions, more severe left atrial compression, and more indentation of the right atrial wall. Echocardiography plays an essential role in diagnosis and management of large pericardial effusions after open heart surgery. Patients with large pericardial effusions who are clinically stable need only medical management, including serial echocardiograms, but drainage is indicated if the cardiovascular or respiratory status worsens. Certain echocardiographic findings indicate a high probability of tamponade.

Adult↗
PubMed1985

Self-administered intravenous analgesia during labour. A comparison between pentazocine and pethidine.

Pentazocine or pethidine was administered to healthy parturients up to the time of delivery using a self-demand (self-administration on demand) intravenous apparatus, the Cardiff Palliator. Good analgesia was obtained with both drugs. The patients receiving pethidine exhibited side-effects (nausea, vomiting and drowsiness), whereas there were no side-effects among those receiving pentazocine. Apgar and neurobehavioural scores of the babies of mothers in both groups were the same and did not differ from those of a third group of babies, the mothers of whom had received 4-hourly intramuscular pethidine on demand according to the usual hospital routine. The self-administration technique proved a safe and effective means of providing analgesia during labour and delivery, with pentazocine having a decided advantage over pethidine because of its lack of side-effects.

Adult↗
PubMed1980

Complications of transurethral resection of bladder tumors: prevention, recognition and treatment.

Between 1931 and 1971, 373 patients underwent transurethral resection of bladder tumors for cure or for control of the neoplasms. Complications included perforation of the bladder wall (5 per cent), hemorrhage requiring transfusion (13 per cent), infection (24 per cent) and postoperative mortality (1.3 per cent). Patients in whom perforations occurred had approximately twice as many infections and twice as much hemorrhage as the entire group but there were no postoperative deaths of those with perforations. Morbidity and mortality can be reduced in patients with perforation by 1) using isotonic irrigating fluid, 2) avoiding over-distension of the bladder, 3) maintaining postoperative free drainage through the catheter and 4) diagnosing and treating hyponatremia.

Hemorrhage↗
PubMed1977

Changes in grade and stage of recurrent bladder tumors.

A retrospective study with adequate followup of 5 years of longer of 114 patients who had transurethral resection for cure or control of bladder tumors and in whom there were 1 or more recurrences is reported. There was recurrence of the tumor in a higher grade in 19 per cent of the cases and in a higher stage in 22 per cent. The interval between the treatment of the original tumor and a recurrence in a higher grade or state varied from 0.25 (3 months) to 27 years. When a low grade or low stage tumor recurs in a higher category in less than 3 years more aggressive treatment should be considered.

Follow-Up Studies↗