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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 379 records · Page 21Linked to original sources
PubMed1990

Fate of antacid gel in the stomach. Site of action and interaction with food.

The site of action of a high-power Al-Mg antacid gel (buffering capacity 70 meq/10 ml) and its interaction with food was examined in 10 healthy volunteers. Combined pH-metries in antrum and corpus were performed in each volunteer on four occasions. In a randomized study design, antacid or placebo were given 1 hr after either a protein or a carbohydrate pancake, of which only the former had any acid-buffering capacity. Before the meal, pH was higher in the antrum than in the corpus (median antrum: 3.2, corpus 1.5). In the corpus, a protein pancake but not a carbohydrate pancake raised the pH (median pH after protein pancake: 3.5; after carbohydrate pancake: 1.4). In the antrum, the protein pancake had no effect, but the carbohydrate pancake decreased the pH (median pH after protein pancake: 3.1; after carbohydrate pancake: 2.0). The antacid had no effect in the corpus after either pancake. It raised intraluminal pH markedly in the antrum after a carbohydrate pancake (median antral pH before antacid: 2.0; after antacid: 3.3), whereas its effect in the antrum was weak after a protein pancake. In vitro experiments were conducted to explain the in vivo results: in contrast to a carbohydrate pancake, a protein pancake reduced the buffering capacity of the antacid by direct interaction. In conclusion, the effect of an antacid gel on intragastric pH is predominantly localized in the antrum and is attenuated in the presence of proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

In vitro activity of the new semi-synthetic polypeptide cilofungin (LY121019) against Aspergillus and Candida species.

The in vitro activity of cilofungin (LY121019), a new semi-synthetic antifungal agent was evaluated. Potent activity was seen against Candida albicans and Candida tropicalis, with almost identical MIC and MFC results, whereas no activity was seen against any isolates of Candida parapsilosis or three Aspergillus spp. However, MICs were dependent on medium and test conditions chosen. It is concluded that cilofungin has good activity against some medically important yeasts in vitro, and that its in vitro activity depends on the method used.

Aspergillus↗
PubMed1990

Inactivity of terbinafine in a rat model of pulmonary aspergillosis.

In a model of bronchopulmonary aspergillosis terbinafine did not improve survival of experimental animals in doses up to 80 mg/kg/day despite adequate lung concentrations. Pretreatment and aerosolization of the compound were also ineffective. Terbinafine was markedly less active in vitro when serum was used instead of Yeast-Nitrogen-Glucose-broth. It is concluded that a lack of bioavailability in the presence of serum may explain the lack of activity of terbinafine in experimental aspergillosis.

Aerosols↗
PubMed1990

Changes in the spectrum of organisms causing bacteremia and fungemia in immunocompromised patients due to venous access devices.

A significant increase in the use of vascular access devices has changed the spectrum of organisms causing bacteremia and fungemia at Memorial Sloan-Kettering Cancer Center. This paper documents the 1988 laboratory experience with bacteremia and fungemia and contrasts some of that data with information obtained in 1984. In 1988, 439 tunnelled-catheters and 355 ports were inserted in patients; 2,778 organisms were subsequently recovered from 933 episodes of bacteremia and fungemia. Fifty-percent of the episodes of bacteremia and fungemia were vascular access device-related. Compared to 1984, the relative incidence of bacteremia due to gram-positive organisms increased from 33 to 43%, polymicrobic cultures increased from 24 to 27%, and the number of organisms with colony counts greater than 100 cfu/ml increased from 24 to 44%. In 1988, device-related sepsis was often caused by Acinetobacter spp., Bacillus spp., Corynebacterium spp., pseudomonads other than Pseudomonas aeruginosa, and coagulase-negative staphylococci. Infection was also caused by species of flavobacteria, Micrococcus, and Rhodotorula. Efforts required for identification of many of the newer pathogens have escalated material and personnel costs.

Adult↗
PubMed1990

An unusual case of craniofacial fibrous dysplasia presenting in early infancy.

Fibrous dysplasia (FD) of bone is one of the most frequently encountered anomalies of skeletal development. It may involve one or more bones and, particularly when polyostotic, is sometimes associated with abnormal skin pigmentation and endocrine abnormalities. FD occurs mainly in large limb bones, ribs, and craniofacial bones in older children and young adults. Usually craniofacial involvement is detected because of local swelling or asymmetry of the face or head. Neurological symptoms, primarily due to involvement of the foramina, have been reported but are not common. Infantile fibrous dysplasia of the craniofacial region has rarely been reported.

Angiography↗
PubMed1990

An ELISA-inhibition assay for antibody to human immunodeficiency virus core antigen (p24).

An ELISA-inhibition assay based on commercially available HIV-1 p24 antigen tests was developed for detecting p24 antibodies. The test is specific and simple. p24 antibody was detectable in all p24 antigen negative Western blot positive sera, but was detectable infrequently in antigen positive sera. Sera from patients with indeterminate HIV-1 reactions (individuals without evidence of HIV-1 infection who nevertheless had p24 antibody) were p24 antigen negative and p24 antibody negative in the ELISA-inhibition reaction.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Use of the genealogical method in the exploration of chronic illness: a research note.

This paper briefly describes how the genealogical method, as derived from Foucault's work, might be used to explore the problem of chronic illness. The genealogical method is differentiated from other qualitative methods, from epidemiology, and from the history of ideas. Finally, the particular relationship, within the genealogical method, of method itself and its object of study is outlined.

Chronic Disease↗
PubMed1990

Posterior fossa medulloblastoma in childhood: treatment results and a proposal for a new staging system.

Seventy-two children with posterior fossa medulloblastoma were diagnosed at the Hospital for Sick Children, Toronto, from 1977 to 1987 and treated by standard methods. The 5- and 10-year survival and disease-free survival rates were 71% and 63%, and 64% and 63%, respectively. Total tumor resection, as determined by the surgeon was the most significant favorable prognostic factor. Post-operative meningitis, a residual enhancing mass lesion on the post-operative, pre irradiation CT scan and dissemination to the brain or cord at diagnosis were unfavorable factors. These four easily definable factors were used to define a staging system with prognostic significance. Five-year disease-free survival rates were for Stage I (total resection, no adverse factor) 100%, Stage II (total resection with one or more adverse factor or less than total resection with no other adverse factor) 78%, and Stage III (less than total resection with one or more adverse factor) 18%. Evaluation of treatment results in medulloblastoma requires that these prognostic factors be known.

Adolescent↗
PubMed1990

Training trainers: a new approach for community medicine.

During 1985, two separate one-day seminars for trainees and trainers in South East Thames Regional Health Authority highlighted the need for a 'training the trainers' course to be run for trainers throughout the Region. This was held during 1987 and this paper gives a descriptive account of the course, highlights the lessons learnt, and summarises the evaluation obtained from participants. Thirteen trainers started the course, one changed jobs and left the Region, leaving twelve completing the course. Spread over nine months, the course included an initial weekend but was mainly run on a day release basis. The facilitators for the course, a psychologist and sociologist, had teaching experience in running similar courses for GP trainers. The course emphasised an adult learning model in which the trainer enabled the trainee to identify and meet their learning needs through appropriate support and facilitation. Although the career change from clinical work to public health medicine is likely to be more traumatic than other transitions within clinical medicine, the approach is applicable on a much wider basis.

Adult↗
PubMed1990

Intraorbital wood. Detection by magnetic resonance imaging.

The authors present two cases in which intraorbital wooden foreign bodies remained undetected after initial ophthalmologic examination and radiologic investigation which included plain orbital x-rays, orbital computed tomography (CT) scans, and, in one case, orbital ultrasound. In each case, subsequent magnetic resonance imaging (MRI) showed a well-delineated low-intensity lesion suggestive of a retained foreign body. Investigation of a case of suspected wooden foreign body in the orbit should include an MRI scan if there is no contraindication, and no foreign body has been defined on CT scan, ultrasound, or plain orbital films.

Adolescent↗
PubMed1990

Peripheral nerve involvement in the Rett syndrome.

Clinical and neurophysiological studies were performed on 4 girls aged 9 to 19 years with the Rett syndrome (RS) (stages II and III). In addition to constant foot deformity (pes planus) and brisk tendon reflexes in the lower limbs, they showed muscular atrophy of the calves and mild atrophy of the extensor digitorum brevis muscle. Motor NCVs were within normal values for age, but distal latencies in two girls and compound action potential in one were abnormal, suggesting mild distal, predominantly motor neuropathy. The upper limbs showed nothing abnormal except for mild hand deformities. Neuropathology in 2 autopsy cases (aged 11 and 17 years, stage IV) and sural nerve biopsies in three girls aged 2, 3 and 17 years, all clinical stage II-III without inanition, revealed mild distal axonopathy without demyelination. Selected axons in sural nerve of a girl aged 17 and in the dental pulp of a girl aged 9, both at clinical stage II, showed increased numbers of neurofilaments. Skeletal muscle in two girls aged 11 and 17 years (both stage IV) exhibited mild alterations in the sarcoplasmic reticulum with occasional disordered myofibrils and tubular structures in the Z-filaments, but no neurogenic atrophy or abnormal mitochondria. The reported data do not support spinal denervation (motor neuron degeneration) in RS, but suggest late onset denervation due to mild distal axonopathy of hitherto unknown origin.

Adolescent↗
PubMed1990

Acute transverse myelopathy in children.

Twenty-three children with acute transverse myelopathy (ATM) are reviewed. Antecedent minor trauma or exercise was reported in 10 patients. Despite a positive history in 7 patients no preceding infection was documented. Two patients had a history of less severe ATM followed by recovery prior to a second more severe episode. The most common initial symptom was back pain and the most prominent clinical signs were weakness, sensory level and sphincter disturbances. Myelography and CT myelography at presentation was performed to exclude a compressive lesion. Spinal cord enlargement was demonstrated in 6 of 21 cases. Magnetic resonance imaging (MRI) of the spinal cord, performed in one patient, showed enlargement of the cord. Poor prognostic features were severity of weakness at the time of maximum deficit and a delayed onset of recovery. Maximum motor recovery occurred at a mean of 6 1/2 months but did not occur in one patient until 1 1/2 years. Normal or good outcome was obtained in 64%.

Acute Disease↗
PubMed1990

Serologic responses to Pneumocystis carinii antigens in health and disease.

Serum antibodies to human Pneumocystis carinii antigens were measured in greater than 400 specimens from different population groups by the immunoblotting technique. Serologic responses varied during the first 2 years of life, but in children greater than or equal to 2 1/2 years and in adults antibodies to a 40-kDa band were found in greater than 85% of the specimens; antigens to bands of 66, 92, and 116 kDa were also detected frequently. The prevalence of serum antibodies in immunosuppressed patients varied at different institutions and was usually lower than that of healthy controls. Seven (41%) of 17 patients with single episodes of pneumocystosis and 13 (93%) of 14 patients with recurrent episodes followed sequentially developed active serum IgM and/or IgG antibody responses to the 40-kDa antigen. Serologic responses to P. carinii were also detected, though less frequently, by immunofluorescence. These data suggest that the 40-kDa antigen is a major marker of P. carinii infection and that immunoblotting is useful in measuring serum antibody responses to the organism in both normal and immunocompromised hosts.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Delayed and progressive multiple suture craniosynostosis.

A considerable amount of information is available on various types of craniosynostoses. The patient exhibiting single suture synostosis that progresses to involve multiple sutures is distinctly uncommon, as is the patient exhibiting delayed synostosis involving all of the calvarial sutures. We report a group of 11 such patients with progressive and delayed holocalvarial synostosis. Most patients exhibited features of raised intracranial pressure or developmental delay, and in all patients symptoms were relieved after surgery. The diagnostic and therapeutic implications of this type of presentation in craniosynostosis are discussed.

Child↗
PubMed1990

Impact of asymptomatic congenital cytomegalovirus infection on size at birth and gestational duration.

Cytomegalovirus (CMV) is the most common viral agent causing congenital infection in humans, affecting 0.2 to 2.4% of all live births. Symptomatic congenital CMV infection has previously been shown to cause low birth weight and prematurity. Whether or not asymptomatic congenital CMV infection, which represents the majority of cases (90 to 95%), affects intrauterine growth or gestational duration is unknown. Using a population of 146 infants with asymptomatic congenital CMV infection and 1419 controls from two socioeconomically diverse populations (biracial low income and white mid- to upper income), determinants of body size (birth weight and crown-heel length) were investigated using multiple regression techniques. We found that congenital infection following the transmission of maternal primary and "unknown" CMV infection resulted in a significant mean birth weight deficit of 163 g (P less than 0.04) for the low income term infants (blacks and whites), but not in the mid- to upper income white infants. Newborns with congenital infection following the transmission of maternal reactivated (recurrent) CMV infection were significantly shorter by a mean of 1 cm (P less than 0.03) than controls, a finding that was consistent regardless of socioeconomic status or race.

Birth Weight↗
PubMed1990

Pharmacokinetics of aerosol amphotericin B in rats.

The distributions of amphotericin B (AmB) in tissue were compared after intraperitoneal or aerosol administration. Rats were sacrificed 24 h after receiving single or repeated daily doses; AmB concentrations in tissues were determined by high-performance liquid chromatography. After intraperitoneal doses of 4 mg/kg of body weight per day for 7 days, mean concentrations of AmB were 122.7, 55.2, and 4.31 micrograms/g in the spleen, liver, and lung, respectively. After aerosol doses (aero-AmB) of 1.6 mg/kg per day, the mean concentrations of AmB in the lung were 2.79 micrograms/g after a single dose and 9.88 micrograms/g after four doses, while the drug was undetectable (less than 0.1 micrograms/g) in serum, spleen, liver, kidney, and brain. The half-life of elimination of AmB from the lungs was 4.8 days according to serial sacrifices done after a single dose of 3.2 mg of aero-AmB per kg. Treatment with 60 mg of aero-AmB per kg was well tolerated and produced no histopathologic changes in the lungs. The aerosol route was much more efficient than the systemic route in delivering AmB to the lungs, and it limited the accumulation of AmB in other organs. Because AmB is eliminated slowly, infrequent dosing schedules can be used. These pharmacokinetic characteristics and its proven effectiveness in an animal model make aero-AmB a highly promising new method for the prevention of pulmonary aspergillosis. Aero-AmB should also be considered for use as an adjunct to intravenous AmB for treatment of fungal pneumonias.

Aerosols↗
PubMed1990

Detection of Candida antigenuria in disseminated candidiasis by immunoblotting.

Immunoblotting (Western blotting) was used to detect Candida albicans antigens in urine of 10 patients with disseminated candidiasis who had two or more positive blood cultures. Twelve urine samples were examined; and antigenuria was found in five of six patients with C. albicans infections, in one patient with a mixed Candida infection (including C. albicans), and in one of two patients with C. tropicalis infection. All except one specimen was collected from 2 to 12 days after initiation of amphotericin B therapy. Positive samples showed different numbers of bands in Western blots with an antigen that had an apparent molecular weight of 47,000 in common. This antigen was not found in the urine of patients who had more than 5 days of therapy for candidiasis and who were responding to therapy. The results suggest that Western blotting for C. albicans antigens in urine may be a useful method for the diagnosis of disseminated candidiasis and for evaluating antifungal treatment.

Amphotericin B↗