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Biomedical subjects

J White

Publications and source records attributed to J White.

At least 469 records · Page 26Linked to original sources
PubMed1986

A useful technique for computerized tomography directed needle biopsy.

This technique uses a simple, inexpensive device to facilitate a previously proved method of obtaining cytologic specimens with a Chiba needle under CT guidance. The plastic sheath could be scored with metric markings and would further facilitate its use as a depth gauge. This method obviates the need for multiple scans required to place the needle at the appropriate depth, thereby decreasing the length of the procedure and unnecessary radiation to the patient.

Biopsy, Needle↗
PubMed1986

The effectiveness of psychological intervention in primary care: a comparative analysis of outcome ratings.

A series of consecutively referred outpatients were independently rated, on a treatment outcome measure, by psychologists, general practitioners and the patients themselves. Statistical comparisons revealed high inter-rater agreement and indicated that 43% of the patients had reliably achieved either moderate or marked improvement and 75% had shown at least slight improvement. Favourable outcome was particularly associated with the psychological treatment of anxiety and stress disorders. These results are discussed with reference to previous reports.

Adult↗
PubMed1986

Circadian periodicity of grass pollen.

Estimations of atmospheric grass pollen concentrations at an urban site were made at two hourly intervals on 67 days over a 5-year period when the average daily grass pollen concentration was 100/m3 or higher. Daily grass pollen concentrations rose from a morning minimum to reach a maximum in the early evening, falling gradually during the night. These results were compared with similar estimations made during 1 year at a rural site. Grass pollen concentrations at the rural site reached their maxima approximately four hours earlier than those at the urban site and corresponded well with maximum recorded values of sunshine, wind and temperature, and minimum values of relative humidity.

Air↗
PubMed1985

Membrane fusion activity of the influenza virus hemagglutinin. The low pH-induced conformational change.

The hemagglutinin (HA) spike glycoprotein of influenza virus catalyzes a low pH-induced membrane fusion event which releases the viral genome into the host cell cytoplasm. To study the fusion mechanism in more detail, we have prepared the ectodomain of HA in water-soluble form by treating virus particles with bromelain. Under mildly acidic conditions (pH less than or equal to 5.8), the ectodomain undergoes a conformational change which we found to be biochemically and immunologically equivalent to that in native viral HA. It became sensitive to proteinase K, it exposed new antigenic epitopes in its HA1 chain, and it acquired amphiphilic properties, notably the ability to bind to liposomes. The attachment to liposomes exhibited the same pH dependence and rapid kinetics as the conformational change and was mediated by HA2. The nature of the attachment resembled that of an integral membrane protein except that the bound HA was partially removed by base. As observed for virus fusion, attachment is independent of divalent cations and lipid composition. Temperature was found to be a critical parameter only with dimyristoylphosphatidycholine vesicles where attachment was partially blocked below the major phase transition. These and other results obtained indicated that the low pH-induced conformational change in the isolated ectodomain is equivalent to that occurring in intact viral HA, and that its attachment to liposomes can serve as a model for the initial stages in the HA-induced membrane fusion reaction.

Animals↗
PubMed1985

Lines of BPV-transformed murine cells that constitutively express influenza virus hemagglutinin.

We have developed and characterized several murine cell lines that constitutively express either the full-length, membrane-bound form of influenza virus hemagglutinin (HA) or a truncated version of the protein (HAsec) that lacks the carboxyterminal anchoring sequences and is secreted from cells. cDNAs encoding HA or HAsec were linked to the murine metallothionein-I promoter or the SV40 early promoter, and inserted into plasmids containing the transforming DNA fragment of bovine papilloma virus (BPV). The resulting vectors were introduced into three cultured lines of murine cells--C127, NIH3T3 and MME--either alone or in the presence of a plasmid that carries the aminoglycoside transferase gene of Tn5. The resulting lines of MME cells contained 1-5 copies of the vector in an integrated state and expressed low levels of HA (approximately 10(4) molecules/cell). In contrast, lines of C127 and NIH3T3 cells were obtained that express up to 5 X 10(6) molecules of HA per cell or secrete approximately 10(7) molecules of HAsec per cell per 24 h. Some of these cell lines carry multiple (30-200) copies of the vector in an integrated state; in others, the vector is propagated as unit-length episomes or as oligomers. Both the membrane-bound and secreted forms of HA expressed in these cell lines display a more extensive pattern of glycosylation than HA or HAsec synthesized in simian cells and they are transported to the cell surface more slowly. Pulse-chase experiments suggest that the step which limits the rate at which HA and HAsec travel down the secretory pathway occurs in the rough endoplasmic reticulum before the molecules are transferred to the Golgi apparatus. Using indirect immunofluorescence in combination with a cell sorter, we have shown that the level of expression of HA within cloned populations of producing cells can be variable. However, greater than 90% of the cells in certain cell lines display considerable quantities of HA on their surface, as judged by their ability to bind red blood cells in large numbers. We have taken advantage of the membrane fusion activity of HA to effect the fusion of erythrocytes to these cells and to deliver the contents of red cell ghosts into the cells' cytoplasm.

Animals↗
PubMed1985

An epidemic of influenza in the population of Niue.

An epidemic of influenza A occurred in the Niue population during May-June 1983. The infection was introduced by two index cases returning from New Zealand to the village of Makefu. The epidemic started in this village and then spread rapidly around the island. The incidence of infection was calculated to be 41 per 100 population based on 1981 census figures. There was no predilection for the infection to affect any particular age bracket, although the elderly were over-represented amongst the hospital admissions because of greater severity of illness in this age group. Two deaths occurred, and 3.4% of cases received treatment in hospital. Apart from generalised symptoms (fever, body pain, and headache), respiratory symptoms, particularly cough, were prominent. Gastrointestinal symptoms were reported in a minority. The average duration of illness was 6 days. Virology results indicated that the epidemic was due to influenza A/Bangkok/1/79(H3N3). Paired serological studies also revealed five cases of dengue fever. Previous records reveal that epidemics of influenza are a frequent occurrence in Niue, although not a major cause of mortality since the 1950s. It is suggested that early treatment of complications is the most important measure to decrease the impact of influenza and that measures such as isolation of cases, restriction of population movement and quarantine of incoming cases may be useful to prevent the propagation of epidemics in a small and isolated population.

Adolescent↗
PubMed1985

The T cell receptor: the alpha and beta chains define idiotype, and antigen and MHC specificity.

Three independent T cell hybridomas were isolated that have identical specificities for antigen and products of the major histocompatibility complex (MHC). All three react with the same clone-specific antireceptor antibody, and Southern blots show all three contain the same rearranged alpha and beta genes. Variants of one of these hybridomas, DO-11.10, were isolated that had lost the ability to respond to antigen plus MHC. These proved to have lost the DO-11.10-specific alpha or beta genes or both. Fusion of alpha-loss variants to beta-loss variants restored reactivity. These results indicate that the specific recognition of antigen plus MHC is determined solely by the alpha/beta-containing T cell receptor.

Animals↗
PubMed1985

An efficient method for introducing macromolecules into living cells.

The hemagglutinin (HA) of influenza virus was used to obtain efficient and rapid bulk delivery of antibodies and horseradish peroxidase (HRP) into the cytoplasm of living tissue culture cells. By exploiting HA's efficient cell surface expression, its high affinity for erythrocytes, and its acid-dependent membrane fusion activity, a novel delivery method was developed. The approach is unique in that the mediator of both binding and fusion (the HA) is present on the surfaces of the target cells. A recently developed 3T3 cell line which permanently expresses HA, Madin-Darby canine kidney cells infected with influenza virus, and CV-1 cells infected with a simian virus 40 vector carrying the HA gene were used as recipient cells. Protein-loaded erythrocytes were bound to the HA on the cell surface and a brief drop in pH to 5.0 was used to trigger HA's fusion activity and hence delivery. About 3 to 8 erythrocytes fused per 3T3 and CV-1 cell, respectively, and 75-95% of the cells received IgG or HRP. Quantitative analysis showed that 1.8 X 10(8) molecules of HRP and 1.4 X 10(7) IgG molecules were delivered per CV-1 cell and 6.2 X 10(7) HRP molecules per 3T3 cell. Cell viability, as judged by methionine incorporation into protein and cell growth and division, was not impaired. Electron and fluorescence microscopy showed that the fused erythrocyte membranes remained as discrete domains in the cell's plasma membrane. The method is simple, reliable, and nonlytic. The ability to simultaneously and rapidly deliver impermeable substances into large numbers of cells will permit biochemical analysis of the fate and effect of a variety of delivered molecules.

Animals↗
PubMed1985

The use of pNJ5000 as an intermediate vector for the genetic manipulation of Agrobacterium Ti-plasmids.

The use of broad-host-range plasmids derived from RP4 as intermediate vectors for the transfer of narrow-host-range recombinant plasmids from Escherichia coli to Agrobacterium tumefaciens as a preliminary to marker exchange is described. Recombinant plasmids having a ColE1 type origin were linked to the RP4 derivative. Cointegrate formation appeared to take place by RecA-independent, homologous recombination within a short piece of DNA derived from the beta-lactamase gene of Tn1/Tn3 carried by both vector components, so that it never disrupted the recombinant portion of the construction. pNJ5000 provides an unstable intermediate vector for use in marker exchange experiments, while its stable relative pNJ1020 provides a carrier for use in binary vector systems.

Cloning, Molecular↗
PubMed1985

Brain metabolism as measured with positron emission tomography: serial assessment in a patient with familial Alzheimer's disease.

This paper presents, for the first time, repeated assessments of cerebral metabolism and neuropsychological competence in early Alzheimer's disease. Regional cerebral metabolic rates for glucose were measured with positron emission tomography and 18F-fluoro-2-deoxy-D-glucose on three occasions at 8-month intervals, in a 57-year-old man with Alzheimer's disease of 2 1/2 years' duration and with a family history of neuropathologically confirmed Alzheimer's disease. Data were compared with mean cerebral metabolic rates from 12 healthy men. No differences in regional cerebral metabolic rates for glucose were found on the initial patient scan, whereas metabolism on the second and third scans was reduced significantly in the parietal lobes and bilaterally in some parietal lobe regions. Memory loss was demonstrable at the first scan, but then and at later scans, other aspects of cognitive performance remained within normal limits (Wechsler Adult Intelligence Scale, Boston Naming Test, Two-dimensional Block Construction). The results show that memory loss can precede a measurable reduction of cerebral metabolism in early Alzheimer's disease, but that later reductions in parietal lobe metabolism may not be accompanied by additional measurable neuropsychological deficits.

Aged↗
PubMed1985

Effect of vasoactive intestinal polypeptide on the canine cardiovascular system.

Our purpose was to determine the effect of vasoactive intestinal polypeptide (VIP) on the cardiovascular system with special emphasis on coronary vascular effects. In section I, VIP was infused into six healthy and six cobalt-cardiomyopathic dogs at two infusion rates (0.02 and 0.05 micrograms/kg/min). Left ventricular end diastolic pressure and mean systemic pressure fell significantly in both groups. Heart rate rose in both, and maximum systolic dP/dt increased in the myopathic group. Cardiac output and regional blood flows were determined by serial left atrial injections of radioactive 15 +/- 3 mum (mean +/- SD) microspheres. In both groups, blood flow increased significantly to the esophagus, pancreas, atria, and ventricles and to the endocardial and epicardial regions of the left ventricular free wall. Blood flow to the brain decreased. In section II, VIP was infused intravenously at 0.1 micrograms/kg/min into six anesthetized dogs with coronary sinus flow, pulmonary artery, and systemic artery catheters inserted. Cardiac index rose from baseline (3.1 +/- 0.5 to 4.8 +/- 1.3 L/min/m2, P less than 0.005), as did coronary blood flow (90 +/- 25 to 159 +/- 54 ml/min, P less than 0.005) during the VIP infusion. Myocardial oxygen consumption rose from 14.1 +/- 3.9 to 19.8 +/- 5.4 ml/min (P less than 0.001), but the aorta-to-coronary sinus O2 difference decreased from 157 +/- 19 ml/L to 132 +/- 42 ml/L (P less than 0.05), and the percent O2 extracted from coronary blood also decreased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

The antigen-specific, major histocompatibility complex-restricted receptor on T cells. VI. An antibody to a receptor allotype.

We have prepared a monoclonal antibody, KJ16-133, from the cells of a rat immunized with the purified receptor for antigen plus I-A of a BALB/c T cell hybridoma, DO-11.10. Unlike most other monoclonal anti-receptor antibodies that have been described before, KJ16-133 is not clone specific. It reacts with approximately 20% of the receptors on T cells of normal BALB/c mice. It also reacts with about the same percentage of antigen-specific, major histocompatibility complex (MHC)-restricted or allogeneic I-region specific T cell hybridomas. Reaction of KJ16-133 with a given T cell hybridoma does not seem to depend on the antigen specificity or MHC-restricting element of the T cell in question. The determinant recognized by KJ16-133 has some unexpected properties. It is absent in several strains of mice including SJL/J and SJA/20, but present on the T cells of most other commonly used strains. The determinant recognized therefore does not map to Igh. Our experiments suggest that a clone-specific "antiidiotypic" antibody and KJ16-133 recognize determinants on different parts of the receptor. For example, the binding of a clone-specific antibody to target T cells is relatively temperature insensitive, whereas KJ16-133 binds well to cells at 37 degrees C but poorly to cells at 4 degrees C. The determinant recognized by a clone-specific antibody is sensitive to reduction and alkylation of the receptor, whereas KJ16-133 reactivity is not. Finally, binding of KJ16-133 at saturating concentrations to target T cells does not block the binding of a clone-specific antibody. Similarly, binding of a clone-specific antibody only marginally inhibits binding of KJ16-133. Taken together, these results suggest that KJ16-133 is directed against an allelic determinant on T cells that may be close to the membrane, and not in the receptor binding site for antigen plus MHC. The antibody may recognize an allele of a constant region isotype, or an allele of a J region.

Animals↗
PubMed1984

Influenza in Melbourne, 1982. Epidemiology and virology.

The major features of the outbreaks of influenza A and B, which occurred in Melbourne during the winter of 1982, are described. Diagnoses of influenza A or influenza B were established in 310 patients by virus isolation, immunofluorescence, and serological tests. Immunofluorescence was found to be a valuable, rapid, but considerably less sensitive, test than virus isolation, and serodiagnosis was the test of choice either when patients did not present or when specimens were not collected until late in the illness. The results of haemagglutination-inhibition tests performed with a panel of monoclonal antibodies suggest that at least two recognizably different strains of influenza A and influenza B were circulating in the community.

Adolescent↗