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Biomedical subjects

R G Wright

Publications and source records attributed to R G Wright.

At least 55 records · Page 3Linked to original sources
PubMed1987

Morphometric analysis of thyroid cell aspirates.

One hundred and nineteen patients with thyroid nodules underwent fine needle aspiration cytology. Fifty eight were subsequently shown to have multinodular goitre: 36 had a follicular adenoma; 12 follicular carcinoma; and 13 papillary carcinoma on paraffin section. Morphometry performed on the aspirated cells stained by Papanicolaou and Giemsa methods showed significant differences in mean nuclear area and nuclear perimeter between groups of patients with benign thyroid nodules and those with malignant nodules. The wide variation in the mean nuclear areas and perimeters, however, severely limits the diagnostic use of morphometry in individual aspirates.

Adenocarcinoma↗
PubMed1987

Association between type of medication instruction and patients' knowledge, side effects, and compliance.

The authors measured knowledge about medication and its side effects, impact of side effects, and compliance in 30 chronic outpatients before and after they participated in two instruction sessions about their medication held one month apart. Instruction consisted of a verbal or a written and verbal presentation and minimum or maximum information about side effects. All patients' medication knowledge increased after both sessions. Those on high doses of neuroleptics given verbal and written information gained significantly more medication knowledge than those given only verbal information. After instruction, more patients knew about specific side effects, including tardive dyskinesia, and both patients given only verbal instruction and those given minimum information about side effects had fewer problems with side effects. Instruction did not affect compliance.

Adult↗
PubMed1985

Invasive carcinoma of the cervix in young women.

The cases of 194 women aged 40 years of age or less who had been diagnosed as having invasive cervical cancer in Queensland during 1972-1981 were reviewed retrospectively. Medical records contained a previous cervical cytological report for 89 women, with 18 of these having had a negative result of a smear test within two years of the diagnosis of invasive cancer. Cytological review of five of the 18 cases revealed neoplastic cells in three cases, and possible sampling inadequacies in the other two. Gynaecological symptoms had been present in seven of the 18 patients at the time of the negative result of cytological examination, and these persisted until the diagnosis was eventually made. A high index of suspicion is required when symptoms persist in spite of negative results of cytological examination and we recommend a review of the smear, a repeat smear examination with adequate sampling and referral for colposcopic examination in these circumstances.

Adult↗
PubMed1983

Eosinophilic gastroenteritis presenting as acute intestinal obstruction.

Eosinophilic gastroenteritis is an uncommon condition which usually affects the antrum of the stomach and may occasionally involve the small or large intestine (1). The main clinical feature is usually that of chronic colicky abdominal pain. We report a case presenting as acute small intestinal obstruction due to isolated involvement of the distal small intestine.

Diagnosis, Differential↗
PubMed1982

The ultrastructure of the eye of the mosquitofish Gambusia affinis.

The ultrastructure of the tissue components of the eye of Gambusia affinis, excluding the sensory cells, is described. The cornea consists of two different sections of collagenous layers of different density. The choroid includes an argentea composed of alpha- and beta-melanophores, lipopterinophores and a choriocapillaris associated with the rete mirabile of the choroid body, Bruch's membrane, underlying the retinal pigment layer, can develop complex associations with fibroblasts delimiting the choriocapillaris. The outer section (stroma) of the iris includes several cell types that are not found in the inner or vitread section. In adult Gambusia the lens capsule is well developed, but in two-week-old Sarotherodon larvae the lens epithelium is covered only by a glycocalyx.

Animals↗
PubMed1982

The use of halothane in a patient with asymmetrical septal hypertrophy: a case report.

An elderly patient with demonstrated asymmetrical intraventricular septal hypertrophy and ventriculo-aortic pressure gradient was anaesthetized with nitrous oxide with oxygen, narcotic, and muscle relaxant for abdominal surgery. In addition to the cardiovascular variables customarily monitored, a systolic time interval (STI) measured from the Q wave of the ECG to the foot of the radial pulse (the QF interval) was calculated in milliseconds beat-to-beat by a computer. With anaesthesia, and particularly following the beginning of operation, the QF interval lengthened as an indication of either decreased cardiac inotropy or increased pressure gradient across the aortic outflow tract. When halothane 0.25 per cent was added to the anaesthetic mixture, the QF interval shortened by about 20 milliseconds without an observed change in direct arterial pressure. Since halothane is a cardiac depressant and normally lengthens the STI, it apparently relaxed the muscular stenosis of the ventricular outflow tract and reduced the pressure gradient and, subsequently, the QF interval. By measuring cardiovascular function with this STI, the beneficial action of cardiac depression from low-dose halothane was observed, which would have escaped detection by common monitoring indices.

Anesthesia↗
PubMed1981

Enflurane analgesia in obstetrics.

The effects of enflurane analgesia (approximately 0.5%) were studied in 55 patients during the second stage of normal vaginal delivery and were compared with effects of nitrous oxide (approximately 40%) in 50 similar patients. The enflurane and oxygen mixture was rated satisfactory by 89% of the mothers and 80% of the anesthesiologists. These ratings did not differ significantly from those for nitrous oxide. Obstetricians, however, rated the enflurane and oxygen mixture superior. The newborns of mothers receiving both agents wee vigorous and comparable when assessed by Apgar scores and cord blood gas tensions. The estimate of blood loss was similar in both groups. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly increased from preanesthetic levels with either agent. There was no biochemical evidence of renal toxicity. In neonates of mothers given enflurane, the mean umbilical cord concentration of serum inorganic fluoride ions was 2.4 +/- 0.2 micromoles/L, a value well below that associated with nephrotoxicity.

Adult↗
PubMed1981

The effect of maternal administration of ephedrine on fetal heart rate and variability.

Ephedrine is the most popular vasopressor used in obstetrics to prevent or treat spinal or epidural hypotension. Fetal heart rate (FHR) changes during epidural anesthesia were studied in 71 patients; it was found that ephedrine administration (57 patients) was associated with significant increases in FHR and beat-to-beat variability. These changes were dose related and were not associated with fetal asphyxia as judged by measurement of fetal scalp blood pH or Apgar scores.

Anesthesia, Obstetrical↗
PubMed1980

Effects of ring substituents and linker chains on the bifunctional intercalation of diacridines into deoxyribonucleic acid.

Sedimentation experiments with closed circular duplex PM2 deoxyribonucleic acid (DNA) and viscosity measurements with sonicated rodlike DNA fragments have been performed to investigate unwinding and extension of the DNA helix associated with binding of homologous series of diacridines. When the acridine nuclei are linked via 9-amino substituents with chains permitting interchromophore separation in the critical region between 8.8 and 11.3 A, it is found that substituents at positions 2, 3, and 6 restrict bifunctional intercalation to compounds capable of sandwiching at least two base pairs in the intercalated complex. Unsubstituted diacridines, and derivatives bearing an ethyl group at position 4, can bis-intercalate with a significantly shorter linking chain. The presence of amino groups in the linker does not affect the ability to bis-intercalate but increases the helix unwinding angle by 30--40% and decreases the helix extension per bound ligand molecule by 11--18%. Bifunctional reaction is observed with a diacridine linked via the 4--4' positions showing that 9-aminoacridine can intercalate in at least two major orientations with the 9 or 10 position directed toward the helix axis. Both orientations can be accommodated simultaneously within a single diacridine linked via the 9--4' positions with a bridge sufficiently long to encompass two base pairs. An acridone substituted at positions 4 and 5 with positively charged side chains intercalates with a helix unwinding angle indistinguishable from that of ethidium whereas an uncharged bisacridone failed to yield a detectable complex with DNA. Tilorone dihydrochloride, a structurally similar antiviral drug, was found to intercalate with an unwinding angle approximately half that of ethidium. The potentially bifunctional bisquinoline drug dequalinium causes relaxation of the supercoiling of PM2 DNA but probably not by simultaneous intercalation of both its chromophores.

Acridines↗
PubMed1980

Nature of the reversible white matter lesion in multiple sclerosis. Effects of acute inflammation on myelinated tissue studied in the rabbit eye.

Arthus reactions of different intensities were induced in the rabbit eye using measles vaccine as the immunogen. In the presence of a mild Arthus reaction in the vitreous, myelinated nerve fibre bundles on the retinal surface revealed extracellular oedema together with marked swelling and rupture of astrocyte processes, including those bearing a special relationship to nodes of Ranvier. These changes improved or disappeared over the course of six days. No demyelination occurred. The findings implicate an astrocytic lesion as a possible cause of reversible neurological deficit and conduction block associated with acute inflammation in central white matter.

Animals↗
PubMed1979

Uterine blood flow and plasma norepinephrine changes during maternal stress in the pregnant ewe.

Because maternal stress may adversely affect the fetus, the authors tested the effects of brief episodes (15-60 sec) of maternal stress in 18 awake pregnant ewes. Maternal agitation and stuggling occurred either following non-painful stimuli such as loud noises or sudden movements of personnel (ten animals) or following the brief application of the ewe's skin of a uniform electrical stimulus of 30 volts with a frequency of 167 Hz for 30-60 sec (eight animals). Stimulation of either type produced a 45-50 per cent increase in mean maternal arterial blood pressure and a concomitant 32-52 per cent decrease in uterine blood flow (P less than 0.05). The decreases in uterine blood flow were brief, lasting less than 3 min, and were not associated with fetal asphyxia. Maternal plasma norepinephrine levels were measured following electrically induced maternal stress and were increased 25 per cent. The authors conclude that maternal stress may decrease uterine blood flow secondary to release of endogenous norepinephrine.

Acid-Base Equilibrium↗
PubMed1979

Dopamine treatment of spinal hypotension decreases uterine blood flow in the pregnant ewe.

In seven pregnant ewes, 3--5 min of hypotension resulting from spinal anesthesia decreased uterine blood flow 17 per cent. Dopamine, in doses sufficient to maintain blood pressure at control values (20--40 micrgram/kg/min) for 3--5 min, further decreased uterine blood flow to 56 per cent less than control and increased uterine vascular resistance to 50 per cent more than control. Following 30 min of hypotension, 30 min of dopamine administration in doses sufficient to restore blood pressure to control values (5--20 microgram/kg/min) similarly decreased uterine blood flow to 29 per cent less than control and increased uterine vascular resistance to 35 per cent more than control.

Anesthesia, Spinal↗
PubMed1978

Macrophages, lymphocytes, and plasma cells in the perivascular compartment in chronic multiple sclerosis.

Perivascular cells in CNS tissue from six multiple sclerosis (MS) patients and a patient with motor neuron disease were examined by light and electron microscopy. Lymph node tissue from one MS patient was also examined. CNS perivascular macrophages in both MA and motor neuron disease were found to closely resemble free macrophages elsewhere in the body except that they often contained unusually large primary lysosomes. Cytoplasmic inclusions consisting of membrane-bound stacks of curved linear profiles, presumed to be a product of myelin degradation, were constantly observed in microglia in MS plaques but were rarely observed in perivascular macrophages in the same area. Unidentified cylindrical bodies were observed within cysternae of rough endoplasmic reticulum in some lymph node cells. Quantitative studies of the perivascular cell population in one MS case revealed, in histologically normal white matter 260 lymphocytes and 178 plasma cells per cubic millimeter of fresh tissue. Typical chronic plaque tissue without obvious inflammatory cell cuffing contained 1772 plasma cells per cubic millimeter of fresh tissue. No plasma cells were observed in the CNS in motor neuron disease. The results of this study suggest that perivascular macrophages in the CNS represent a specialized population of monocyte-derived free macrophages, that these cells differ functionally from microglial cells, and that the digestion of myelin breakdown products in MS requires the participation of both cell types. The results also suggest that in some chronic MS cases there is a large, permanent population of CNS plasma cells that persists, like the elevated cerebrospinal fluid IgG level in this disease, for the life of the patient, that these cells, rather than inflammatory cells in fresh lesions, are the major source of this raised IgG, and that the existence of such a population of cells may indicate the continuing expression of antigens in chronic MS lesions in the absence of fresh lesion formation.

Adult↗
PubMed1976

The ultrastructure and calcification of the scales of Tilapia mossambica (Peters).

The scales of Tilapia are surrounded by an envelope of scleroblasts responsible for the production of layers of collagen that constitute the bulk of the scale. The scleroblasts adjoining the lateral face of the oldest scale region gradually atrophy. New Collagen layers are deposited against the inner face of the scale, the adjoining scleroblasts showing evidence of high metabolic activity. Calcification occurs by inotropic deposition of crystals alongside the fibres. There is no sharp demarcation between calcified and non-calcified scale regions, a calcification front gradually moving towards newly formed collagen layers. It is felt that fish scales should be considered as calcified derivatives of dermal collagen layers.

Animals↗