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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 397 records · Page 22Linked to original sources
PubMed1990

Use of immunoblotting to detect Aspergillus fumigatus antigen in sera and urines of rats with experimental invasive aspergillosis.

Immunoblotting was used to detect Aspergillus fumigatus antigen in sera and urines of immunosuppressed rats experimentally infected with A. fumigatus. Organisms were administered by both intravenous and intratracheal injections. Intravenously infected rats developed disseminated aspergillosis, but intratracheally infected rats developed pulmonary disease only. Fungal cultures of blood and urine samples from infected rats were negative. In the urines of intravenously infected rats, antigen was detected 24 to 48 h after infection; in the urines of intratracheally infected animals, antigen was detected on days 4 to 5 after infection. Antigen in serum was detected later than antigen in urine was. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of serum and urine samples, the most strongly reacting antigenic materials were found in the 88-, 40-, 27-, and 20-kilodalton regions. These dominant antigens appeared to be the same as those of control antigens prepared from A. fumigatus grown in vitro. Rabbit antiserum to Aspergillus filtrate antigen was found to be more immunoreactive than antiserum to mycelial or conidial antigen. No mycelium-specific antigens were detected.

Animals↗
PubMed1990

Do-Do abuse.

Three cases of prolonged abuse of Do-Do tablets, an over-the-counter remedy for "coughs, wheezing and breathlessness", are reported. They have an amphetamine-like action and were used as easily obtained amphetamine substitutes, in one case to relieve social anxiety. Withdrawal symptoms similar to those following cessation of amphetamines occurred in two cases. Do-Do tablets are CNS stimulants and their abuse may be accounted for by the fact that they perhaps affect amine neurotransmitters.

Adult↗
PubMed1990

Reproducibility of ambulatory gastric pH recordings in the corpus and antrum. Effect of food, time, and electrode position.

The reproducibility of simultaneous, long-term, ambulatory gastric pH recordings in the antrum and corpus was investigated in nine healthy subjects who underwent three separate, 27-h gastric double pH-metries. Intraindividual reproducibility for the entire 27-h recording period was good in the corpus (Kendall's concordance coefficient, W' = 0.6393, p less than 0.025) but not in the antrum (W' = 0.4806, NS). Analysis of predefined time periods showed that non-meal daytime pH was reproducible in the corpus (W' = 0.6531, p less than 0.025) but not in the antrum (W' = 0.3395, NS), whereas mealtime pH was reproducible in the antrum (W' = 0.7159, p less than 0.005) but not in the corpus (W' = 0.4954, NS); nocturnal pH was not reproducible in either the antrum or the corpus. These results reflect the functional separation of corpus and antrum and their differing responses to food. Thus, studies of gastric acidity over long periods should be conducted in the corpus, whereas studies of gastric acidity over shorter, meal-related periods should be conducted with a second electrode in the antrum.

Adult↗
PubMed1990

Doctor-initiated consultations: a study of communication between general practitioners and patients about the need for reattendance.

It has been suggested that general practitioners have the potential to regulate a large percentage of their workload through their control of 'doctor-initiated' consultations. A survey was made of 300 consecutive consultations in a group practice. After their consultation patients completed a questionnaire asking what advice the doctor had given them on the need to reattend. At the same time the general practitioner completed a similar questionnaire about the need for reattendance and the advice given. The general practitioners judged that 74% of patients definitely or possibly needed to reattend, and only 26% definitely did not need to reattend. The coefficient of agreement between patients' and doctors' views on whether reattendance had been recommended was only 0.41. Thus the room for control of doctor-initiated consultations is limited by both clinical considerations and the apparent difficulty of accurately communicating the doctor's advice on reattendance to the patient.

Communication↗
PubMed1990

Thiobarbituric acid test as a measure of lipid peroxidation in Arab patients with NIDDM.

Increased levels of lipid peroxides have been implicated in the pathogenesis of diabetic complications. A convenient and sensitive method for estimation of lipid peroxide concentration is the quantitative estimation of their metabolic end-product malonyldialdehyde (MDA) expressed in mumol/L using the thiobarbituric acid test. The mean fasting MDA value in the plasma of 26 Arab subjects with NIDDM was significantly higher than in healthy controls (14.3 +/- 8.3 vs 2.3 +/- 3.4, p less than 0.001). Within a group of nine diabetic patients with markedly elevated MDA values (greater than 20 mumol/L), eight subjects had retinal changes, four had evidence of coronary artery disease and three had manifest cerebrovascular disease. Macroproteinuria was documented in only three patients in this same group. The mean body mass index was 28.7 +/- 5.4 and the glycaemic control was unsatisfactory with a mean glycosylated hemoglobin of 10.1 +/- 1.5%. The MDA results in an Arabic population were similar to reports in Japanese and British patients and should prove useful as a laboratory test in assessing the severity of the diabetic state, as well as a complementary test in diagnosis and management.

Diabetes Mellitus, Type 2↗
PubMed1990

Plasma beta-endorphin concentration: response to intensity and duration of exercise.

Twelve college-age men exercised on a bicycle ergometer to VO2max and at 60, 70, and 80% VO2max for 30 min to determine the effects of exercise intensity on plasma beta-endorphin (B-EP). The time course for alterations in B-EP and the relationship to lactate were also examined. Following the VO2max test, the three submaximal intensities were completed on separate days using a counter-balanced design. Blood was sampled from an indwelling venous catheter at rest during exercise and recovery to assess the time course response. B-EP content was determined by radioimmunoassay (Immunonuclear) with less than 5% cross-reactivity to B-LPH. At rest, B-EP content was similar across visits, 4.34 +/- 0.36 pmol.l-1. The 60% intensity did not elevate B-EP at any time measured. B-EP content increased by 15 min at 70% VO2max with a further increase at 30 min. B-EP remained elevated during the 20 min recovery. At 80% VO2max B-EP content increased by 5 min. B-EP continued to increase during the exercise and peaked at 21.91 +/- 2.03 pmol.l-1 5 min into the recovery. Lactate showed a mild correlation with B-EP (r = 0.43) at 80% VO2max. A significant correlation (r = 0.78) between lactate and B-EP did occur with the VO2max test. It is concluded that an exercise intensity of at least 70% VO2max for 15 min is needed to increase plasma B-EP. Furthermore, the higher the exercise intensity the more rapid the onset for increases in plasma B-EP.

Adult↗
PubMed1990

Studies of experimentally induced retinal degeneration: 2. Early morphological changes produced by lipid peroxides in the albino rabbit.

When pure, synthetic lipid hydroperoxides (LHP) were injected into the vitreous body of albino rabbits, electrical activity was decreased in all components of the electroretinogram (ERG) in a progressive and time-related manner. In the early phase morphological changes occurred at the interface between the photoreceptor outer segments and the retinal pigment epithelium (RPE) in response to LHP. These findings commenced within a few hours after injection and continued during the following 2-3 weeks, when the ERG was completely extinguished. Two days after injection, the rod outer segments (ROS) were swollen and damage of the RPE apical villi was observed. This initial event was followed by additional changes in the RPE which embraced swelling, accumulation of residual bodies, complete loss of ROS and enlargement and disruption of Bruch's membrane. The precursors of residual bodies appeared to result from focal, peroxidative damage to ROS discs which apparently rendered these materials undegradable by the RPE. As ROS degeneration continued, the RPE showed hypertrophy and modification. These studies provided evidence for a sequential destruction of the neural retina and RPE during oxidative damage involving lipid peroxidation. The mechanism appeared to differ from that produced by other toxic compounds or those which resulted from vitamin E or A deficiency. This new model system is thought to be useful in 1) explaining differences in susceptibility of inner ROS disks versus other membranes, 2) determining how the RPE metabolizes abnormal ROS, 3) studying RPE reactivity following trauma and/or retinal detachment, and 4) determining factors which produce degeneration of Bruch's membrane.

Animals↗
PubMed1990

Nasal reconstruction with full-thickness cranial bone grafts and rigid internal skeleton fixation through a coronal incision.

The use of iliac and rib bone as onlay grafts to the nasal dorsum often fails because endochondral grafts resorb unpredictably. Membranous cranial bone grafts are less likely to resorb, especially when used with rigid internal fixation techniques. However, when split, they are often too thin and can be difficult to contour. Full-thickness cranial bone grafts were used to achieve nasal augmentation in 26 patients with end-stage nasal skeleton deficiency. All procedures were carried out using only a coronal incision. Grafts were harvested through a craniotomy, carved meticulously, and secured rigidly with miniplates or bicortical screws. Donor sites were reconstructed with split cranial grafts, leaving an intact cranial vault. No graft was lost to infection, and there was no significant donor-site morbidity. In carefully selected patients this method of full-thickness cranial bone graft reconstruction yields good results.

Adolescent↗
PubMed1990

Cervical spine injuries in children.

Cardiorespiratory arrest occurring immediately after multiple injuries is usually assumed to be due to severe cerebral injury, acute hemorrhage, or airway obstruction. We have identified a group of 19 children (mean age, 6.3 years) who presented with absent vital signs (VSA) or severe hypotension, unexplained by blood loss, where these findings were caused by injury to the high cervical spine and cord, demonstrated either by X-ray or postmortem examination. Fourteen had radiologic evidence of injury to the spine between C1 and C3. In two patients the bony injury was at the C6-7 level, while in two patients the cervical spine X-ray was normal. Eighteen of the 19 children were initially resuscitated but died from a combination of hypoxic/ischemic encephalopathy and cerebral injury. Sixteen patients underwent postmortem examination and in 13 there was evidence of cord laceration, up to and including cord transection. These findings demonstrate a distinct pattern of "juvenile" cervical spine injury involving the high spine and cord which results in either apnea and cardiorespiratory arrest, or severe hypotension. This previously unrecognized cause of cardiorespiratory arrest should be considered in all children presenting with VSA after multiple trauma, even when there is no apparent radiologic abnormality of the cervical spine.

Adolescent↗
PubMed1990

Toxoplasma gondii serology in HIV-infected patients: the development of central nervous system toxoplasmosis in AIDS.

Central nervous system (CNS) toxoplasmosis is an important infectious complication of AIDS which requires prolonged treatment. Most cases occur in patients with serologic evidence of prior exposure and therefore appear to result from reactivation of a previously acquired infection. Antibody to Toxoplasma gondii was found in 130 out of 411 patients with AIDS (32%). Of these, CNS toxoplasmosis developed in 31 (24%). By survival analysis, the estimated probability of ever developing CNS infection in antibody-positive individuals was 28%, occurring in 26% of patients within 2 years of the onset of AIDS. All patients with HIV infection should be tested for antibody to T. gondii and monitored for any neurologic change. Methods of prophylaxis for CNS toxoplasmosis in these high-risk patients need to be developed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Comparison of criteria derived by government and patients for evaluating general practitioner services.

A study was carried out to see whether patients' criteria of good health care in general practice were different from those of the government and doctors. A total of 711 patients in a semirural group practice evaluated the importance of 20 criteria describing different facets of care. Half the criteria were derived from Promoting Better Health (health education, easy to change doctors, all children vaccinated, health checks for adults and children under 5, regular screening for cancer, woman doctor available, doctor goes on courses, well decorated premises, convenient surgery times); the other 10 were taken from a preliminary interview study of 24 patients (staff friendly and know me, doctor listens and sorts out problems, same doctor for consultations, nurse on premises, appointments available within 48 hours, waiting time less than 20 minutes, small surgery premises, tests available at surgery). Questionnaires containing 10 pairs of criteria assigned by computer were drawn up and patients asked to give their preference in each pair. The number of times each criterion was preferred was scored and its comparative importance ranked. The three criteria most highly ranked by all patients were having a doctor who listens, having a doctor who sorts out problems, and usually seeing the same doctor (all criteria originated by patients). The three least highly valued were health education, being able to change doctor easily, and well decorated and convenient premises (all criteria originated by the government). The criteria originated by patients as a group scored significantly more highly than those originated by government as a group. In a more competitive general practice environment, in which doctors will be more inclined to satisfy the wishes of patients, officially supported indicators of good quality care might not get the encouragement that the government and doctors think that they deserve.

Adult↗
PubMed1989

Diagnostic criteria for Walker-Warburg syndrome.

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder manifest by characteristic brain and eye malformations. We reviewed data on 21 of our patients and an additional 42 patients from the literature. From this review, we expand the phenotype to include congenital muscular dystrophy (CMD) and cleft lip and/or palate (CLP), and revise the diagnostic criteria. Four abnormalities were present in all patients checked for these anomalies: type II lissencephaly (21/21), cerebellar malformation (20/20), retinal malformation (18/18), and CMD (14/14). We propose that these comprise necessary and sufficient diagnostic criteria for WWS. Two other frequently observed abnormalities, ventricular dilatation with or without hydrocephalus (20/21) and anterior chamber malformation (16/21), are helpful but not necessary diagnostic criteria because they were not constant. All other abnormalities occurred less frequently. Congenital macrocephaly with hydrocephalus (11/19) was more common than congenital microcephaly (3/19). Dandy-Walker malformation (10/19) was sometimes associated with posterior cephalocele (5/21). Additional abnormalities included slit-like ventricles (1/21), microphthalmia (8/21), ocular colobomas (3/15), congenital cataracts (7/20), genital anomalies in males (5/8), and CLP (4/21). Median survival in our series was 9 months. A related autosomal recessive disorder, Fukuyama congenital muscular dystrophy, consists of similar but less severe brain changes and CMD. It differs from WWS because of consistently less frequent and severe cerebellar and retinal abnormalities. We think that WWS is identical to "cerebro-oculo-muscular syndrome" and "muscle, eye, and brain disease."

Brain↗
PubMed1989

Survival, growth and function of damaged cholinergic neurons.

Recent progress has been made in defining the requirements for survival, growth and function of damaged cholinergic neurons of the central nervous system. In particular, the responsiveness of cholinergic neurons to nerve growth factor (NGF) in the regulation of development, cell survival, axon elongation, and response to injury has led to the formulation of the Neurotrophic Hypothesis, a unifying hypothesis of neuronal responsiveness to growth-promoting substances. NGF-mediated effects on cholinergic neurons in culture as well as in the septum, basal nucleus, striatum, and hippocampus, and the ability of NGF to prevent lesion-induced cell death and to ameliorate the effects of aging, provide the foundation for this work. A potential role for glia and microglia in mediating the effects of NGF is proposed.

Acetylcholine↗
PubMed1989

Peritoneovenous shunts palliate malignant ascites.

Fifty-five peritoneovenous shunts (PVS) were implanted in 45 patients (29 LeVeen and 26 Denver shunts). Seventy-five percent of patients experienced relief of symptoms referable to their ascites. The mean survival time post-shunt placement was 33 weeks; however, considerable variation was noted in survival times for the various tumor types (pancreas 7 weeks, ovary 71 weeks). Significant alterations in coagulation parameters consistent with subclinical disseminated intervascular coagulation (DIC) were present in all patients with functioning shunts. These coagulation changes have proven reliable indicators of shunt patency. Shunt revision was necessary in 18 percent of patients. No significant difference in shunt patency was detected when Denver and LeVeen shunts were compared. This experience indicates that PVS offers effective palliation without undue morbidity for malignant ascites. The best results can be expected in those patients with ovarian and breast primary tumors. Because of the short time from onset of disabling ascites until death, PVS is not indicated in the majority of patients with pancreatic cancer.

Adolescent↗
PubMed1989

Inactivation of human immunodeficiency virus in vitro by gossypol.

Gossypol, a polyphenolic aldehyde extracted from cottonseed, is a male anti-fertility agent which has been reported to have anti-viral activity. In this paper we report that gossypol inactivates human immunodeficiency virus (HIV) in an in vitro system. Following exposure of cell-free incubates of HIV to 100 uM gossypol, ultracentrifugation and inoculation of the washed pellet onto H9 cells, there is no evidence of elevated reverse transcriptase activity over 21 days. Treatment with lower concentrations of gossypol reduces the peak and lengthens the time to maximal reverse transcriptase activity compared with control cultures. These observations suggest that gossypol could be used as a vaginal spermicidal/virucidal agent. The mechanism of the in vitro anti-viral action as well as the effect of orally administered gossypol on the infectivity of semen of HIV-seropositive men warrant further study.

Cell Line↗
PubMed1989

Recovery of induced mutations for X chromosome-linked muscular dystrophy in mice.

We have used elevated levels of plasma creatine phosphokinase activity to identify muscular dystrophy phenotypes in mice and to screen the progeny of chemical mutagen-treated male mice for X chromosome-linked muscular dystrophy mutations. We were not successful in identifying heterozygous carriers of these induced muscular dystrophy mutations in greater than 8000 progeny. However, we were highly successful in identifying three additional alleles of the characterized mdx locus. These alleles of mdx were recovered from various mutagen-treated males and they occur on an X chromosome that carries flanking markers that allow us to follow the mutations in genetic crosses and in the development of corresponding mutant stocks. These alleles have been designated as mdx2Cv, mdx3Cv, and mdx4Cv. Preliminary data show that mice with mdx2Cv and mdx3Cv mutations have muscular dystrophic phenotypes that do not grossly differ from the characterized mdx mutation. These additional mdx mutations expand the value of mouse models of X chromosome-linked muscular dystrophy and potentially define additional sites of mutation that impair dystrophin expression.

Animals↗