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Biomedical subjects

A Morris

Publications and source records attributed to A Morris.

At least 19 recordsLinked to original sources
PubMed1992

Maintenance of lower proportions of (n - 6) eicosanoid precursors in phospholipids of human plasma in response to added dietary (n - 3) fatty acids.

Competition between the (n - 3) and (n - 6) types of highly unsaturated fatty acids can diminish the abundance of (n - 6) eicosanoid precursors in a tissue, which in turn can diminish the intensity of tissue responses that are mediated by (n - 6) eicosanoids. The mixture of 20- and 22-carbon highly unsaturated fatty acids maintained in the phospholipids of human plasma is related to the dietary intake of 18:2 (n - 6) and 18:3 (n - 3) by empirical hyperbolic equations in a manner very similar to the relationship reported for laboratory rats (Lands, W.E.M., Morris, A. and Libelt, B. (1990) Lipids 25, 505-516). Analytical results from volunteers ingesting self-selected diets showed an inter-individual variance for the proportion of (n - 6) eicosanoid precursors in the fatty acids of plasma phospholipids of about 5%, but the variance among multiple samples taken from the same individual throughout the day was less (about 3%), closer to the experimental variance of the analytical procedure (about 1%). The reproducibility of the results makes it likely that analysis of fatty-acid composition of plasma lipids from individuals will prove useful in estimating the diet-related tendency for severe thrombotic, arthritic or other disorders that are mediated by (n - 6) eicosanoids. Additional constants and terms were included in the equations to account for the effects of 20- and 22-carbon highly unsaturated (n - 3) fatty acids in the diet. A lower constant for the 20- and 22-carbon (n - 3) fatty acids compared to that for the 18-carbon (n - 3) fatty acid in decreasing the ability of dietary 18:2 (n - 6) to maintain 20:4 (n - 6) in tissue lipids confirmed the greater competitive effectiveness of the more highly unsaturated n - 3 fatty acids in the elongation/desaturation process. Also, a lower constant for direct incorporation of 20-carbon fatty acids of the n - 6 vs. the n - 3 type indicated a greater competitive effectiveness of 20:4 (n - 6) relative to 20:5 (n - 3) in reesterification after release from tissue lipids. The equations may be used in reverse to estimate the dietary intakes of the (n - 3) and (n - 6) fatty acids by using the composition of the fatty acids that had been maintained in plasma lipids.

Aged↗
PubMed1992

Antimicrobial susceptibility of anaerobic bacteria in Auckland 1987-90.

The antimicrobial susceptibility of 292 clinical isolates of anaerobic bacteria was determined by a standard agar dilution method. Metronidazole was the most active agent with only one Bacteroides fragilis, two anaerobic cocci, and Propionibacterium acnes being resistant. For B fragilis itself and other members of the B fragilis group: 35/35 (100%) and 43/44 (98%) respectively, were susceptible to amoxycillin-clavulanic acid; 47/47 (100%) and 55/56 (98%) respectively, were susceptible to cefoxitin; and 20/28 (71%) and 7/25 (28%) respectively, were susceptible to ceftriaxone. All four agents and penicillin were almost always active against anaerobic cocci and Fusobacterium species. All agents were active against clostridium isolates except for cefoxitin where only 47/57 (82%) were susceptible. These results allow comparison with isolates from other locations and may be considered when choosing an antimicrobial agent for prophylaxis or therapy of anaerobic infections.

Amoxicillin↗
PubMed1992

Peripheral mechanical loading and the mechanism of the tremor of chronic alcoholism.

The tremor of chronic alcoholism, although clinically similar to essential tremor, has been considered a distinct syndrome. Its underlying mechanism was analyzed in five patients (none in the acute stages of alcohol withdrawal) hospitalized in an alcohol detoxification program. All five patients performed tracking tasks in which they pursued a linearly moving "target" light with a response light that they controlled by flexion-extension activity of the wrist. Stationary and dynamic targets were used with both isometric and unconstrained wrist mechanical interfaces. Frequency, torque, and displacement tremor characteristics were examined under varying inertial loading or isometric voluntary torque conditions. Two simultaneous tremor components were present in all patients: a prominent 4- to 7-Hz low-frequency peak and a smaller-amplitude 9.4- to 9.6-Hz high-frequency peak. As the inertia of the hand was augmented during unconstrained tasks, the low-frequency peak decreased, while the high-frequency peak was unaffected. As required voluntary effort was increased during isometric testing, the amplitude of the low-frequency peak increased. These findings suggest that the low-frequency peak represents the significant pathologic component of the tremor of chronic alcoholism and that it has a biomechanical reflex mechanism similar to that of the lower-amplitude normal physiologic tremor.

Adult↗
PubMed1992

Improved diagnosis of chronic hepatitis C virus infection by detection of antibody to multiple epitopes: confirmation by antibody to synthetic oligopeptides.

Serum samples from 226 patients covering a wide spectrum of liver disease were tested for antibodies to hepatitis C virus (HCV) using both first and second generation enzyme linked immunosorbent assays. Selected sera were also tested by peptide immunoassays, by the four-antigen recombinant immunoblot assay (RIBA II), and for viral genome by the polymerase chain reaction. Antibody to c100-3 was detected in 61% of patients with chronic non-A, non-B (NANB) hepatitis and/or 46.5% with presumed NANB-related cirrhosis by the first generation test. These figures increased to 77% and 58% when antibodies to recombinant structural and non-structural HCV antigens were sought by the second generation assay. Supplemental testing against peptide Sp75 and Sp65/sp67 confirmed that reactivity of sera by second generation assays was due to antibodies to the additional structural and non-structural antigens. Samples negative by the first generation assay were not confirmed by the supplemental assay using peptides Sp75 and Sp65/Sp67. HCV RNA was detected in 60% of the anti-HCV positive sera tested, most of which were also RIBA II positive. Our findings confirm that the introduction of the structural and non-structural antigens, especially the putative nucleocapsid protein, improves sensitivity of detection of antibodies to HCV, and facilitates diagnosis in patients with "cryptogenic" chronic hepatitis.

Antigens, Viral↗
PubMed1992

Cytokine augmentation of HIV-1 LTR-driven gene expression in neural cells.

The induction of human immunodeficiency virus type 1 (HIV-1) gene expression by cytokines was investigated in cells of central nervous system origin. These were human neuroblastoma, glioblastoma, and astrocytoma cell lines, a murine oligodendroglioma and primary murine astrocyte cultures. The cytokines used were tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta), IL-6, and interferons alpha and gamma (IFN alpha, gamma). Transient transfection of cells with a chloramphenicol acetyltransferase (CAT) reporter gene under the control of the HIV-1 long terminal repeat (LTR) showed significant augmentation following treatment by particular cytokines. TNF alpha was found to augment HIV LTR-directed CAT activity in all cell types. IL-1 beta also activated the HIV LTR reporter gene in glioblastoma, astrocytoma, and astrocyte cells. IL-6 enhanced HIV gene expression in one example only, the primary astrocyte cultures. The interferons generally suppressed expression from the LTR except IFN gamma which produced a twofold rise in the murine glial cells and IFN alpha augmenting expression in one neuroblastoma cell line. No synergy was observed between pairs of activating cytokines tested. The HIV tat gene product was found to be functional in all cells, cotransfection of a tat expression vector transactivating expression from the LTR, with varying degrees of efficiency. In some cell lines the combination of an activating cytokine and tat resulted in an enhancement above that obtained by cotransfection of tat alone. In others, the level of CAT activity did not significantly change. Analysis of nuclear extracts from cytokine-treated cells further implicated the involvement of NFKB in the induction of HIV-1 gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The use of verbatim and schematic strategies in the recall of written stories by deaf and hearing children.

It is, in general, difficult to study cognitive structures in deaf children: in particular, the enquiry into the nature of their story-knowledge structures (or story schemata) is fraught with thorny methodological problems. While some of the available evidence would suggest that typical deaf children do not read "story schematically", theirs may be a problem of lack of access to (rather than absence of) such cognitive structures. On the other hand, it cannot be assumed a priori that cognitive structures are identical in deaf and hearing children. A study using a picture arrangement method is described, the results of which support the view that the story schemata of deaf children are basically similar to those of hearing children. Deaf children, however, may not utilise the presence of certain story features which, if presented to hearing children, lend strength and salience to the story line.

Attention↗
PubMed1992

Urinary incontinence: correlates among cognitively impaired elderly veterans.

1. Although a range of factors can contribute to urinary incontinence in long-term care residents, it is more closely associated with a decline in both cognitive and functional status. 2. Although all subjects had to be cognitively impaired to participate in the study, the incontinent group had a significantly lower mean score on the mental status examination than did the continent group. 3. Incontinent subjects were more dependent in activities of daily living and took significantly longer to carry out functional tasks specifically related to toileting. 4. Urinary incontinence was strongly associated with a history of urinary tract infections, positive urine cultures, epididymitis, hematuria, and fecal incontinence. Medical diagnosis, medications, and affective status were not associated with the problem.

Case-Control Studies↗
PubMed1991

Two isoforms of the muscle acetylcholine receptor alpha-subunit are translated in the human cell line TE671.

We have previously reported the existence of 2 forms of mRNA for the human muscle acetylcholine receptor (AChR) alpha-subunit, thought to be generated by alternate splicing of a primary transcript and to encode 2 alpha-subunit protein isoforms. The 2 predicted alpha-subunit isoforms, differing by the insertion of 25 amino acids at position 58/59, have been synthesized from cRNA transcripts using rabbit reticulocyte lysates; these protein isoforms could be differentiated by immunoprecipitation using antibodies raised against synthetic peptides. The antibodies were used to demonstrate translation of both AChR alpha-subunit isoforms in the rhabdomyosarcoma (muscle) cell line TE671, in an approximate 1:1 ratio.

Amino Acid Sequence↗
PubMed1991

Duodenal ulcer relapse after eradication of Helicobacter pylori.

Thirty-six patients with healed duodenal ulcers, 27 infected with Helicobacter pylori and nine uninfected, were followed for up to 12 months to determine the rate of ulcer relapse. Eight patients withdrew over the follow up period. At one year, 15 of 20 (75%) infected patients and one of eight (13%) uninfected patients had relapsed, p less than 0.05. Eradication of H pylori favourably influences the natural history of duodenal ulcer recurrence. Significant patient morbidity may be prevented by using measures to eradicate H pylori during or after duodenal ulcer healing.

Amoxicillin↗
PubMed1991

Catfish trauma.

Explore the source record for details and available documents.

Adolescent↗
PubMed1991

Measuring environmental health status in Oukasie, 1987.

This article reports on some aspects of the physical environment and on environmental health services at Oukasie. The data were collected over a weekend in August 1987 by an interview and by direct inspection of the environment using a standard schedule. We had a 100% response rate on the interviews. There was a mean of 2.2 +/- 1.6 persons per room in the households, with brick houses being less crowded than non-brick houses. Private yards were generally kept very clean. Bucket latrines were unhygienic and used by an average of 4 families. No latrine was built to accepted standards. Garbage collection and emptying of the bucket latrines by the municipality seemed to be unsatisfactory. Our overall impression was that where responsibility for maintenance of hygiene is either undefined, such as the collection chambers of bucket latrines, or a responsibility of the public authorities, such as garbage collection and water drainage, there is an unsatisfactory state of hygiene. Where maintenance of cleanliness is clearly a private responsibility, such as the maintenance of the cleanliness of private yards, the general status of hygiene is good.

Black or African American↗
PubMed1991

Community health survey of Oukasie, 1987.

A series of surveys were conducted at the request of the community of Oukasie to determine certain public health information in the township, a peri-urban black community. This article describes two of these surveys. The first, a census and partial demographic survey, showed that the total black population was around 6,300 with a mean household occupancy of 4.1. Some of the estimated vital statistics calculated were an infant mortality rate of 36.6/1,000, a crude birth rate of 28.0/1,000, a crude death rate of 6.5/1,000, and a general fertility rate of 99.3/1,000. The second survey into the nutritional and immunisation status of children aged under 5 years showed that 20% of children were underweight and nearly half were incompletely immunised at 1 year of age. These studies, involving local community and student volunteers, were rapidly and inexpensively done and provide basic public health information.

Adolescent↗
PubMed1991

Enalapril versus digoxin in patients with congestive heart failure: a multicenter study. Canadian Enalapril Versus Digoxin Study Group.

Patients with New York Heart Association functional class II or III heart failure stabilized on furosemide therapy were entered into a randomized controlled trial comparing enalapril (n = 72) and digoxin (n = 73). End points were clinical outcome, treadmill exercise capacity and echocardiographic left ventricular dimensions. Improvement in clinical outcome was defined as a reduction of at least one functional class or withdrawal because of an adverse clinical event. After 4 weeks, 13 patients receiving enalapril showed improvement, 55 had no change and 9 manifested deterioration compared with 7, 49 and 17, respectively, in the digoxin group (p less than 0.01). After 14 weeks, 13 patients receiving enalapril showed improvement, 50 had no change and 9 manifested deterioration, compared with 14, 37 and 22, respectively, in the digoxin group (p less than 0.025). More patients in the digoxin group were withdrawn because of an adverse clinical event (p less than 0.05). Exercise time and percent fractional shortening improved in both groups (p less than 0.001 and less than 0.05, respectively), with no significant difference between groups (p greater than 0.50). Both rate-pressure product and subjectively evaluated exertion during submaximal exercise were reduced only in the enalapril group. Although the majority of patients in both groups did well, those receiving enalapril experienced fewer adverse clinical events and had less fatigue during submaximal exercise.

Adult↗
PubMed1991

High incidence of vancomycin-associated leucopenia and neutropenia in a cardiothoracic surgical unit.

A retrospective case record review was undertaken to determine the incidence of vancomycin-associated leucopenia in a cardiothoracic surgical unit. Forty-nine patients received 50 courses of vancomycin therapy. Nine patients (18%) developed reversible leucopenia (white cell count less than 4000 x 10(6)/l) or neutropenia (polymorphonuclear leucocyte count less than 1500 x 10(6)/l). Four patients (8%) had severe neutropenia (less than 1000 x 10(6)/l). The median total dosage associated with leucopenia and neutropenia was 30 g, range 22-56 g. The median duration of treatment in leucopenic and neutropenic patients was 22 days, range 6-28 days. The median recovery time to a normal white cell count was 4 days, range 1-11 days. Patients who developed leucopenia on vancomycin therapy did not differ from those who did not with respect to age, total vancomycin dose, length of therapy, underlying illness, incidence of cardiac surgery or use of concomitant medications. Vancomycin-associated leucopenia and neutropenia is common in patients with cardiothoracic infections, many of whom are on several other medications. White cell counts should be estimated regularly in such patients.

Adult↗
PubMed1991

Visual contrast sensitivity of U.S. Navy jet pilots.

Good visual contrast sensitivity (CS) is often described as a visual capability important for success as a military aviator and so has been suggested as a physical standard for personnel selection and retention. To evaluate this idea, we measured the CS of 135 U.S. Navy fighter pilots ranging in age from 24 to 44 years (mean = 30.20, S.D. = 4.06) and compared these to the CS of non-aviators. We obtained the non-aviator data from published studies of other investigators who used similar procedures with the same widely used, commercially available apparatus (Nicolet CST 2000). In addition to this comparison, we correlated the pilots' CS with their air-to-air target detection distances measured during air combat maneuver training and to their night carrier landing performance scores. The major findings were: 1) The mean CS of the aviators and the non-aviators were within +/- 1.0 S.D. of each other in most instances, and those few instances where a greater difference was found were parsimoniously explained by methodological and procedural factors; 2) sensitivities to different spatial frequencies were highly correlated among themselves, indicating much redundancy among the measurements; 3) there was no evidence of a relationship between CS and air-to-air target detection distances or night carrier landing performance.

Adult↗
PubMed1991

Visual acuity of the U.S. Navy jet pilot and the use of the helmet sun visor.

Visor wear habits, evaluative comments and vision test data were obtained from interviews of 126 Navy fighter pilots. The interviews revealed that many pilots use their helmet sun visor whenever they fly, some use it only during certain flight operations, and others never use it. Study 1 (conducted at 343 cd/m2) revealed a decrease in low contrast visual acuity attributable to helmet sun visor use in the presence of a glare source. These findings prompted a second study of the visual effects of visor transmittance. Low-contrast spot detection, acuity, and contrast sensitivity were measured at an operationally realistic daytime illumination level (6870 cd/m2) in subjects viewing through filters ranging from 6.3% to 50.1% transmission. (Standard visor transmission is 12 +/- 4%.) Results showed that filter density, and consequently the illuminance reaching the eyes, could be varied over a wide range without critically affecting these visual functions. Prevailing environmental illuminance should be considered when selecting sun visors or sunglasses. These results have implications for optimizing visual performance through visors.

Adult↗