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J Martin

Publications and source records attributed to J Martin.

At least 631 records · Page 35Linked to original sources
PubMed1991

Conservation of epitopes recognized by monoclonal antibodies against the separated subunits of influenza hemagglutinin among type A viruses of the same and different subtypes.

Monoclonal antibodies raised against the separated hemagglutinin subunits (HA1 and HA2) of influenza A/Vic/3/75 (H3N2) virus were tested against a large panel of human and avian strains. The epitopes recognized by most antibodies were conserved among subtype H3 viruses, but reactivity of some antibodies with members of other subtypes was also observed. Particularly, the H4 virus reacted with most antibodies directed against the HA2 subunit. These results are discussed in terms of sequence similarities between subtypes and application of these antibodies as subtyping reagents.

Animals↗
PubMed1991

Secondary aortoduodenal fistulas: value of initial axillofemoral bypass.

Between January 1970 and April 1989, 20 patients underwent operation for secondary aortoduodenal fistulas. When the preoperative diagnosis was certain and emergency control of bleeding not required, initial axillofemoral bypass was performed before ablation of the infected aortic prosthetic graft during the same operation. When diagnosis was uncertain or severity of bleeding required emergency laparotomy, the therapeutic plan varied over time. Until 1980, we performed either a direct repair (three cases) or the ablation of the aortic graft followed by secondary axillofemoral bypass (four cases). After 1980, the order of procedures was 1) control of bleeding whenever necessary, 2) axillofemoral bypass, and 3) ablation of the aortic graft. Postoperative mortality was two of 13 in patients undergoing initial axillofemoral bypass, compared with six of seven patients undergoing direct surgery or initial ablation of the aortic graft. Of the 12 patients surviving the postoperative period, three died of aortic stump hemorrhage, four, 12, and 14 months after operation. Two patients had a new aortic graft inserted. Repeat replacement of the abdominal aorta graft was performed in one case and ascending thoracic aortobifemoral bypass in the other because of secondary thrombosis of the axillofemoral bypass. We conclude that initial axillofemoral bypass before dealing with the aortic graft improves the immediate prognosis in operations for secondary aortoduodenal fistulas. This procedure does not, however, preclude the possibility of aortic stump infection which can lead to recurrent aortoduodenal fistula. The risk of infection or secondary occlusion of axillofemoral bypass is minimal. Secondary prosthetic replacement is not systematically necessary.

Aged↗
PubMed1991

The effects of sodium fluoride and stannous fluoride on the surface roughness of intraoral magnet systems.

Four types of intraoral magnets used for retention of overdentures and maxillofacial prostheses were exposed in vitro to SnF2 and NaF to determine the effects of fluoride rinses on surface roughness. The surface roughness (Ra) was measured, after simulated 1, 2, and 5 years' clinical exposure to fluoride (31, 62, and 155 hours). The mean change in Ra was calculated for each period of simulated exposure to fluoride for each magnet type. Two-way ANOVA was used to compare mean change in Ra between magnets within fluorides, and between fluorides within magnets. Paired t tests were used to compare mean change in Ra within fluorides within magnets. The mean change in Ra increased for all magnets after simulated 1, 2, and 5 years of exposure to SnF2 and NaF (p less than 0.03). Using the change in Ra as an indicator for corrosion, PdCo encapsulated SmCo5 magnets and their keepers demonstrated the least corrosion with either fluoride.

Analysis of Variance↗
PubMed1991

Retinal pigment epithelium response and the use of the EOG and Arden Ratio in depression.

Supersensitivity to light in depression has been observed with both neuroendocrine and ophthalmological assessment methods. The biological defect underlying this abnormality may be localized in either the photoreceptors, the retinal pigmented epithelium, or some interaction of the two. The present study assessed responses of the retinal pigmented epithelium (RPE). All subjects underwent thorough ophthalmological and mood assessments. The electrooculogram (EOG) was used to measure standing potentials of the RPE in response to light and dark in 20 normal controls and 20 unmedicated depressed patients. Both groups were matched for age, sex, time of day for the procedure, and prior lighting history. Reproducibility of the EOG measure on two independent occasions for 13 control subjects had an intrasubject reliability coefficient of 0.70. The mean +/- SD Arden Ratio (light peak/dark trough) of the control group (2.13 +/- 0.42) compared to the depressed group (2.28 +/- 0.72) showed no statistical difference. There was, however, a significant difference between groups in response to darkness; depressed patients had a lower standing potential in the dark compared to controls, suggesting supersensitivity to light. No difference between groups was detected in standing potentials at baseline or in response to light. Supersensitivity to light in depression may be related to abnormal function of the RPE, but the inherent reliability of the EOG precludes the use of this instrument in pursuing this hypothesis.

Adult↗
PubMed1991

Five new TaqI DRB1 polymorphisms.

Five new restriction fragment length polymorphisms (RFLPs) using TaqI and a DR beta probe have been found in Caucasian individuals. The families of these individuals have been tissue typed by serological and RFLP methods. The new RFLPs are similar to previously established RFLPs except for the size of one fragment in each instance.

Blood Donors↗
PubMed1991

Clinical evaluation of ticarcillin, with clavulanic acid, and gentamicin in the treatment of febrile episodes in neutropenic children.

To assess the clinical efficacy of ticarcillin, with clavulanic acid, and gentamicin, we conducted a prospective one year study of febrile episodes in neutropenic children. Seventy-five episodes were evaluated in 42 children. The response rate was 32% during persistent neutropenia, whilst another third of episodes responded with neutrophil recovery. Positive blood cultures occurred in 21 episodes and 20 of 24 micro-organisms belonged to the 'community' flora, i.e. organisms carried by healthy people (Streptococcus pneumoniae, Staphylococcus aureus, Branhamella catarrhalis and Escherichia coli). The route of pathogenesis was endogenous in 76% of the patients. There was a substantial superinfection-related morbidity (14%) and mortality (7%), related to emergence of resistance during and after parenteral antibiotic administration. The poor clinical response, combined with emergence of resistance, lead to the conclusion that this combination is of limited value as a first line regimen for neutropenic patients.

Child↗
PubMed1991

Expression of two xylanase genes from the rumen cellulolytic bacterium Ruminococcus flavefaciens 17 cloned in pUC13.

Two distinct xylanase genes (designated xynA and xynB) were subcloned in pUC13 from non-homologous restriction fragments of Ruminococcus flavefaciens 17 DNA originally isolated in lambda EMBL3. The products of the two genes showed similar pH optima for hydrolysis of oat spelt xylan (around 5.5) and had little or no activity against carboxymethylcellulose. Trace activities against p-nitrophenyl (pNP) cellobioside and pNP-xyloside were detected in clones containing xynA, but not in one harbouring xynB. The xylanase associated with clones carrying xynA produced mainly xylobiose and xylose from xylan and did not give hydrolysis of xylobiose, while that encoded by xynB produced mainly xylobiose and higher xylo-oligosaccharides from xylan. There was evidence of increased expression, at the RNA level, of these two genes, and of another cloned region encoding multiple activities including xylanase, in R. flavefaciens 17 grown with xylan, as compared with cellobiose, as energy source. Total cell-associated xylanase and beta-xylosidase activities, and supernatant xylanase activity, were shown to be similarly induced in xylan-grown R. flavefaciens, 17.

Animals↗
PubMed1991

Difference in activity properties and subcellular distribution of neutrophil alkaline phosphatase between normal individuals and patients with trisomy 21.

Biochemical, cytochemical characteristics and electron microscopy subcellular distribution of neutrophil alkaline phosphatase (NAP) were analysed in blood and/or smear samples from 39 trisomy 21 patients (Down's syndrome) aged 11.5-18 years (mean 15.5 years) and 55 normal subjects aged 12-20.5 years (mean 17 years). All patients were karyotyped. NAP cytochemical procedures were carried out on all subjects; biochemical NAP determinations were made in 10 patients and 20 controls; ultrastructural electron microscopy of AP was performed in three patients and four normal subjects. Neutrophil alkaline phosphatase from patients with trisomy 21 displayed the following changes: (1) a significant increase of enzyme activity, (2) a high thermal lability of enzyme. Electron microscope morphology exhibited large deposits of NAP reaction product associated with the plasma membrane and intracellular main organelles, like phosphasomes. The NAP biochemical and cytochemical characteristics suggest that trisomy 21 neutrophils contain a non-specific AP isoenzyme, closely related to the early placental form.

Adolescent↗
PubMed1991

Transformation by the oncogenic latent membrane protein correlates with its rapid turnover, membrane localization, and cytoskeletal association.

The latent membrane protein (LMP) of Epstein-Barr virus (EBV) has a short half-life (V. R. Baichwal and B. Sugden, J. Virol, 61:866-875, 1987; K.P. Mann and D. Thorley-Lawson, J. Virol, 61:2100-2108, 1987), is localized in patches in the membrane (D. Liebowitz, D. Wang, and E, Kieff, J. Virol, 58:233-237, 1986), and associates with the cytoskeleton in EBV-immortalized B lymphocytes (D. Liebowitz, R. Kopan, E. Fuchs, J. Sample, and E. Kieff, Mol. Cell. Biol. 7:2299-2308, 1987; K. P. Mann and D. Thorley-Lawson, J. Virol. 61:2100-2108, 1987). Deletion mutants of LMP that are either positive or negative in the induction both of anchorage-independent growth of BALB/c 3T3 cells (V. R. Baichwal and B. Sugden, Oncogene 4:67-74, 1989) and of cytotoxicity in a variety of cells (W. Hammerschmidt, B. Sugden, and V. R. Baichwal, J. Virol. 63:2469-2475, 1989) have been studied to identify the biochemical properties of this protein that correlate with its effects on cell growth. Mutant LMP proteins that are metabolically stable, do not associate with the cytoskeleton, and exhibit a diffuse plasma membrane localization also do not induce anchorage-independent growth in rodent cells or cytotoxicity in B lymphoblastoid cells. In contrast, a mutant of LMP that is functionally identical to the wild-type protein has a half-life, membrane localization, and cytoskeletal association similar or identical to those of LMP. These results are consistent with the hypothesis that LMP's rapid turnover, association with the cytoskeleton, and patching in the membrane are required for it to affect cell growth.

Animals↗
PubMed1991

Apolipoprotein (apo) E inhibits the capacity of monosodium urate crystals to stimulate neutrophils. Characterization of intraarticular apo E and demonstration of apo E binding to urate crystals in vivo.

Factors that modulate the ability of monosodium urate crystals to stimulate leukocytes could regulate gouty inflammation. Lipoproteins that bear apo B-100 and apo E bind to urate crystals and suppress crystal-neutrophil interaction. In this study, we observed that urate crystals, coated with apo E of monocyte origin, had a diminished ability to stimulate neutrophils. Apo E was also detected on the surface of urate crystals recovered from gout patients. Thus, we analyzed apo E in noninflammatory synovial fluid, and found it to be associated with particles of heterogeneous size and of predominantly alpha and pre-beta electrophoretic mobility. Local articular synthesis of at least a portion of synovial fluid apo E was suggested because (a) the synovial fluid/plasma concentration ratio of apo E was significantly higher than that for both apo B and apo A-I, which are not widely synthesized by extrahepatic tissues, (b) cultured rheumatoid synovial cells in first passage secreted apo E, (c) a portion of synovial fluid apo E was heavily sialylated. We conclude that synovial fluids contain apo E that appears partly of local origin. Apo E binds to urate crystals and could modulate gouty inflammation.

Apolipoproteins E↗
PubMed1991

Antigenic homology among gram-negative organisms isolated from cattle with clinical mastitis.

This study examined the degree of serologic homology among mastitis pathogens. Antibodies were raised against the Rc mutant, Escherichia coli O111:B4 (strain J5) and affinity purified against lipopolysaccharide derived from the Ra mutant, Salmonella typhimurium TV119. These antibodies reacted with a battery of unrelated Gram-negative bacteria in whole cell ELISA. Bacteria with strong cross-reactions included a heterologous, smooth E. coli, Salmonella dublin, S. typhimurium, Salmonella newport, and Pseudomonas aeruginosa. Recognition of Klebsiella pneumoniae and Bordetella bronchisepticum was observed, but reactions were weaker than with the other isolates. The reduced recognition of these isolates probably reflects a masking effect of the bacterial capsule and variations in lipopolysaccharide structure. The polyclonal antibody did not recognize a Gram-positive isolate, Staphylococcus aureus. These immunoglobulins were then tested using whole cell ELISA against a panel of bacteria recovered from the mammary glands of cattle with clinical mastitis. Marked reactivity was noted against a variety of Gram-negative pathogens. Gram-positive isolates had lower recognition by Gram-negative core antigen specific immunoglobulin. The results suggest immunization with rough mutant bacteria may have broad application in the prevention of coliform mastitis.

Animals↗
PubMed1991

Moderate hypothermic versus normothermic total cardiopulmonary bypass for coronary artery surgery: a retrospective study.

A retrospective analysis of 200 patients who underwent coronary artery bypass surgery between 1987 and 1990 was performed to ascertain whether there was any difference in morbidity or mortality with normothermic versus moderate hypothermic perfusion. Total cardiopulmonary bypass was used in all patients. 100 patients (Group H) were perfused using moderate (28-32 degrees C) hypothermia and the remaining 100 patients (Group N) were perfused at normothermia (37 degrees C). Both groups were comparable for age, weight, BSA, and perfusion time (Group H-mean 64 years, 82 Kg., 1.92 m2, 94 minutes; Group N-mean 63 years, 82 Kg., 1.90 m2, 90 minutes). Mean perfusate temperature in Group H was 31 degrees C, while the normothermic group was maintained at 37 degrees C. Both groups were perfused to maintain a venous oxygen saturation between 65-70 percent and arterial pressure between 60-70 mmHg. The cardiac index during bypass for Group H was lower (2.32 +/- .19 L/m2/min) than Group N (2.55 +/- .11 L/m2/min) (p less than 0.001). Mean arterial pressure for Group H was 69 +/- 12.4 mmHg and for Group N was 63 +/- 7.8 mmHg (p less than 0.001). Oxygen transfer for Group N (159 +/- 43 cc/min) was higher than Group H (113 + 31cc/min) (p less than .001). Metabolic acidosis was not observed in either group. Group H required vasodilators while Group N required vasoconstriction to maintain pressures on total bypass between 60-70 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The latent membrane protein oncoprotein resembles growth factor receptors in the properties of its turnover.

The latent membrane protein (LMP) of Epstein-Barr virus functions as an oncogene in rodent cell lines (D. Wang, D. Liebowitz, and E. Kieff, Cell, 43: 831-840, 1985; V. R. Baichwal and B. Sugden, Oncogene, 2: 461-467, 1988) and, therefore, is likely to be essential for immortalization of human B-lymphocytes by Epstein-Barr virus. LMP has a short half-life in Epstein-Barr virus-infected B-lymphoblastoid cells (V. R. Baichwal and B. Sugden, J. Virol., 61: 866-875, 1987; K. P. Mann and D. Thorley-Lawson, J. Virol., 61: 2100-2108, 1987) and in LMP-transformed rodent cell lines (V. R. Baichwal and B. Sugden, Oncogene 2: 461-467, 1988). The hypothesis that the turnover of LMP functions to down-regulate LMP activity has been tested by determining whether the turnover of LMP resembles that of several receptors for growth factors and neurotransmitters. The rapid turnover of LMP in transformed BALB/c 3T3 cells is blocked by cycloheximide, which indicates that turnover requires ongoing protein synthesis. Greater than 90% of newly synthesized LMP is present at the cell surface within 20 min of synthesis, and the detectable protein remains at this location for up to 6 h. If cells are grown in the presence of cycloheximide such that turnover of LMP is inhibited, an internalized pool of LMP can be detected; this observation indicates that turnover of LMP is likely to be preceded by internalization and that, once internalized, LMP is rapidly degraded. Also, this result indicates that the degradation of LMP, as opposed to its internalization, requires ongoing protein synthesis. The turnover of LMP and its biological activity (as assayed by cytotoxicity) are not regulated by factor(s) present only in serum, because the half-life of LMP in cells maintained in serum-free medium does not differ from that in the same cells grown in 5% calf serum. The rapid turnover, the requirement of protein synthesis for turnover, and the internalization of LMP are consistent with the functioning of this protein as a (ligand-dependent or independent) cell surface receptor.

Animals↗