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Biomedical subjects

J Robertson

Publications and source records attributed to J Robertson.

At least 163 records · Page 9Linked to original sources
PubMed1991

Visual acuity in infants after vitrectomy for severe retinopathy of prematurity.

During the course of the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP), 98 infants (129 eyes) from the randomized segment of the trial developed total retinal detachment from retinopathy of prematurity (ROP) before the 1-year examination. The authors report as a case series the results of acuity card assessment of monocular grating acuity at 1 year in 53 infants (71 eyes) postvitrectomy and in 45 infants (58 eyes) who had retinal detachments but who did not undergo retinal reattachment surgery. The decision to undertake and the surgical technique used for a retinal reattachment procedure was not part of the randomized CRYO-ROP trial. Two eyes of one infant had pattern vision at the lowest measurable threshold after vitrectomy. None of the remaining eyes that had undergone vitrectomy and none of the eyes that did not undergo vitrectomy showed evidence of pattern vision. The relatively poor visual outcomes in this case series suggest that efforts are well-spent in attempting to prevent retinal detachment in ROP.

Cryosurgery↗
PubMed1991

The use of duplex sonography in the detection of colorectal hepatic metastases.

Conventional imaging techniques are of limited value in identifying small liver metastases. Indirect methods of measuring blood-flow have shown that metastases may be associated with subtle changes in liver blood-flow. Doppler ultrasonography has the ability to measure liver blood-flow directly. In this study, the role of duplex sonography in the detection of hepatic metastases was evaluated. Hepatic arterial and portal venous blood-flows were measured in 30 patients awaiting surgery for colorectal cancer and 16 controls. The ratio of hepatic arterial: portal venous blood-flow (Doppler flow ratio; DFR) and the ratio of hepatic arterial:hepatic arterial and portal venous blood-flow (Doppler perfusion index; DPI) were calculated. Clear separation of the DPI and DFR values of controls and patients with histologically confirmed liver metastases was observed (P less than 0.001). The data suggest that the measurement of liver blood-flow by duplex sonography may be of value in the diagnosis of colorectal liver metastases.

Adult↗
PubMed1991

Detection of hepatic metastases using duplex/color Doppler sonography.

Current imaging modalities are unable to detect small liver metastases because of limited resolution and contrast differentiation. The association between liver metastases and altered liver blood flow has been demonstrated by dynamic scintigraphy, but the clinical feasibility of this test has been questioned. In this study a novel approach to detecting liver metastases was assessed by measurement of liver blood flow using a duplex/color Doppler System. Hepatic arterial and portal venous blood flows were measured in 16 controls, 50 patients with gastrointestinal cancer, and 6 patients with breast cancer. The ratio of hepatic arterial to total liver blood flow (Doppler perfusion index, DPI) and the ratio of hepatic arterial: portal venous blood flow (Doppler flow ratio, DFR) were calculated. The DPI and DFR values of controls and patients with overt liver metastases were clearly separated (p less than 0.0001). The results suggest that duplex/color Doppler ultrasound measurement of hepatic perfusion changes may be of value in the detection of liver metastases.

Adult↗
PubMed1991

Direct isolation in eggs of influenza A (H1N1) and B viruses with haemagglutinins of different antigenic and amino acid composition.

Influenza A (H1N1) and influenza B viruses from clinical samples were isolated in the amniotic cavity of embryonated hens' eggs by classical techniques and propagated in the allantoic cavity. Virus progeny from different eggs which had been inoculated with virus material from the same clinical sample possessed antigenically distinguishable haemagglutinins (HAs). Virus progeny of some eggs possessed HAs which were serologically identical to those of virus isolated in parallel in mammalian (MDCK) cells. These egg-grown viruses possessing HAs with the antigenic phenotype of mammalian cell-grown viruses appeared to be antigenically related to epidemic influenza virus because post-infection human sera reacted to high titre with the virus HA. Specific nucleotide changes were detected in the HAs of the viruses isolated directly in eggs at positions 163 and 189 for influenza A (H1N1) viruses or positions 141 and 196 to 198 for influenza B viruses. Egg-isolated viruses which possessed the antigenic phenotype of mammalian cell-grown viruses retained glycosylation sites at positions 163 and 196. The viruses isolated directly in embryonated hens' eggs which possessed the HA antigenic phenotype and glycosylation sites of MDCK cell-grown virus can, unlike the latter viruses themselves, be used as candidate influenza vaccine viruses.

Amino Acid Sequence↗
PubMed1991

Changing central venous catheter lines: evaluation of a modification to clinical practice.

As the costs of providing quality nursing care increase, the conservation of both human and material resources becomes increasingly important. This study arose from a need to evaluate the procedure used to change central venous catheter (CVC) lines following the substitution of a time-consuming and costly traditional procedure with a simpler procedure that used less resources. Using a convenience sample of inpatients in the oncology unit who had either fully or partially implanted infusion devices in situ, rates of infection for CVC exit sites were calculated for the 12-month periods preceding and following the introduction of the revised procedure. No significance differences were found between the infection rates at CVC line exit sites; however, the cost of undertaking the procedure decreased following a change of equipment used in the line-change procedure. Data collection methods are discussed, together with results and implications for clinical practice.

Asepsis↗
PubMed1991

Automated genetic analysis.

Automation of several new, non-traditional techniques for genetic analysis has now become possible. A new system is described that performs gel electrophoretic analysis of DNA including VNTRs, gene segments, and restriction enzyme digests. The instrument detects emitted fluorescence from labeled DNA segments in real-time as they electrophore through a gel matrix past a scanning laser beam. Molecular length determination and band quantification is accomplished by comparison to an in-lane standard. Since DNA segments can be labeled and detected with any of four different dyes, the simultaneous analysis of similar length segments from different reactions within a single lane is possible. PCR products are analyzed for research in the areas of human identification and genetic disease. These examples illustrate how automation will play key role in this new era of genetic analysis.

Automation↗
PubMed1990

Recurrent torsion of the spermatic cord and scrotal testis in a stallion.

A stallion was twice referred for evaluation of scrotal swelling and signs of pain. The first admission followed a 3-year period of recurrent signs of left-sided scrotal pain and swelling. After the removal of the left testis because of testicular torsion, the stallion was returned to service. The conception rate was 82% for the next breeding season. Two years after initial surgery, the stallion again was evaluated because of acute signs of right-sided scrotal pain and swelling. Right-sided testicular torsion was detected and corrected, and the testis was sutured in place. The stallion's conception rate for the following breeding season was greater than 90%.

Animals↗
PubMed1990

A host-cell-selected variant of influenza B virus with a single nucleotide substitution in HA affecting a potential glycosylation site was attenuated in virulence for volunteers.

An influenza B virus was passaged in man (virus A) and then in human embryo trachea (C) and into embryonated eggs (D) or directly into eggs (B). Virus A, B, and C had the same (cell-like) haemagglutinin phenotype on reaction with selected monoclonal antibodies while D had an "egg-like" phenotype. The viruses were administered at a dose of 1,000 TCD50 (for MDCK cells) by intranasal inoculation to groups of 27 or 28 volunteers. Viruses A, B, and C all produced disease in six to eight volunteers, whereas D produced no illness and only four volunteers were infected. The viruses shed by the volunteers were indistinguishable from those with which they were inoculated. The haemagglutinin genes of the viruses were sequenced and changes were detected indicating amino acid substitutions at position 196-198 in the attenuated egg-grown virus D whereby a potential glycosylation site present in the other viruses was lost.

Amino Acid Sequence↗
PubMed1990

Trisomy 21 in transient myeloproliferative disorder.

Transient leukemia in phenotypically normal children is rare. A newborn child in whom fever and tachypnea developed at age 2 days had a white blood cell count of 20.1 x 10(9)/L and many abnormal blast cells. Chromosome analysis of spontaneously dividing cells from the blood showed these to have trisomy 21, and 80% of cells in the marrow were also trisomic. No trisomic cells were present in skin fibroblast cultures. At age 6 months, at which time the blood film appeared normal, trisomic cells were no longer present.

Cells, Cultured↗
PubMed1990

Justifying nursing practice: the scientific rationale.

The development of theories underlying the scientific basis for the performance of nursing care begin with sufficient curiosity to enable the exploration of the relationships between practice and outcome. For any one problem, a sound scientific rationale reflects not only 'how' (strategy), but 'why' (topic) a particular action has been chosen to resolve a particular problem and, in addition, clearly demonstrates the relationship of these elements in the light of patient assessment and nursing diagnosis.

Curriculum↗
PubMed1990

Induction of chromosomal aberrations and sister chromatid exchanges by alpha particles in density-inhibited cultures of mouse 10T1/2 and 3T3 cells.

We examined the dose-response relationships for the induction of cell killing, chromosomal aberrations and sister chromatid exchanges (SCE) by 220 kV X-rays and 5.3 MeV alpha particles from a 238Pu source. The cells were irradiated in density-inhibited, confluent cultures. The D0 values for the X-ray and alpha particle survival curves were 1.7 Gy and 0.7 Gy, and the extrapolation numbers 2.5 and 1.0, respectively, for mouse 3T3 cells. Chromosomal aberrations increased linearly with dose for alpha-radiation and roughly with the square of dose for X-rays in 3T3 cells. At 37 per cent survival, 1.0 chromosomal aberration per cell was induced by X-rays and 1.7 per cell by alpha-radiation, but the fraction of cells without aberrations was similar. In confluent holding recovery experiments there was a 50 per cent reduction in X-ray-induced aberrations during the first 4 h of confluent holding. No decline in alpha-induced aberrations was observed with holding times up to 24 h. The dose-response relationship for the induction of SCE by X-rays increased linearly with doses up to 100 cGy in both 3T3 and 10T1/2 cells, then declined, reaching nearly background levels after 400 cGy. The induction of SCE increased rapidly in these cell lines with doses of 2.5-5.0 cGy of alpha-radiation, then declined. The relative biological effectiveness (RBE) was 15-25 for the induction of SCE by low doses (2.5-5.0 cGy) of alpha particles.

Alpha Particles↗
PubMed1990

The prevalence of psychotic symptoms in homeless adolescents.

This study was designed to gather data on psychotic symptoms in a sample of homeless adolescents. The sample included adolescents who were located in street sites as well as adolescents who were currently using shelter services. Ninety-six adolescents participated in this study (mean age = 16.1 years). The results indicated that 29% of the sample reported the experience of four or more psychotic symptoms on the Diagnostic Interview Schedule psychotic symptom index. These results suggested that the endorsement of psychotic symptoms is a relatively prominent feature of the self-report of psychopathology among homeless adolescents. These symptoms did not only include reports of paranoid ideation, which may be generally elevated as part of the stress of street life, but also included reports of ideas of reference and auditory hallucinations. Moreover, these symptoms were correlated with reports of affective disturbance, abusive life experience, and a particular type of substance use.

Adolescent↗
PubMed1990

[Evaluation of 196 patients with chronic myeloid leukemia based on a standard prognosis model].

The clinical course of 196 patients with chronic myelocytic leukemia (CML) was studied. Prognostic factors were analyzed using a standard prognostic model. From a univariate analysis of patients with nonblastic Philadelphia chromosome-positive CML, splenomegaly, bone marrow fibrosis, percentage of blasts and promyelocytes in the peripheral blood and LDH activity were shown to be factors with a significant negative influence on survival. However, age and the platelet count did not influence survival. The standard prognostic model, generated with the 4 variables (1) percentage of blasts and promyelocytes, (2) spleen size, (3) platelet count and (4) age did not provide a useful representation of risk status in this heterogenous patient population. However, the addition of further variables (LDH, additional chromosomal aberrations, percentage of basophiles/eosinophiles and percentage of bone marrow blasts) to the standard model allowed a separation into 2 patient groups: one with low and the other with intermediate to high risk. Our data support the general validity of the prognostic model; however, the applicability of the model may be compromised in hematologic centers with a heterogenous CML population due to the selection of high-risk patients. In this situation additional risk factors may have to be added to the prognostic formula.

Biomarkers, Tumor↗