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Biomedical subjects

B Jones

Publications and source records attributed to B Jones.

At least 271 records · Page 15Linked to original sources

Serological and nucleic acid analyses for HIV and HTLV infection on archival human plasma samples from Zaire.

In order to better understand the genomic diversity and molecular phylogeny of the human retroviruses, the plasmas from 250 Zairean patients collected in 1969 were tested for antibodies to human T-cell lymphoma and human immunodeficiency viruses (HTLV or HIV) using ELISA and confirmatory Western blots and for viral nucleic acids by reverse transcriptase-directed PCR (RT-PCR). Interestingly, none of the patients was confirmed positive for HIV, even though this region is now endemic for HIV-1. However, 74 (30%) and 3 (1%) of the samples were positive for antibodies to HTLV-I and II, respectively. Forty-four of 74 (59%) Western blot-positive Zairean samples were RT-PCR positive for HTLV-I, while 1 of 3 (33%) of HTLV-II-seropositive samples was RT-PCR positive. On the contrary, none of the Western blot-negative or indeterminate samples were RT-PCR positive for either HTLV-I or HTLV-II. We have cloned and sequenced 140 bp of the pol gene flanked by SK110/SK111 from 8 HTLV-I- and 1 HTLV-II-positive archival samples from Zaire. The HTLV-I isolates from Zaire cluster together as a phylogenetic group, diverging from the prototype Japanese HTLV-I (ATK) by a range of 1.4 to 3.6%. Their close homology to some African STLV-I isolates suggests relatively recent interspecies transmission. The Zairean HTLV-II isolate is closely grouped with the HTLV-II substrain of isolates found in Paleo-Amerindians of the New World, making it unlikely that it represents an endemic African strain.

Antibodies, Viral↗

Mucinous adenocarcinoma at the ileocecal valve mimicking Crohn's disease.

Two patients presented to their clinicians with bowel complaints thought to be suggestive of Crohn's disease. The patients were sent for radiological studies to confirm that diagnosis. The radiologic findings in both patients were thought to be consistent with Crohn's disease, although not classical. No further diagnostic studies were initially undertaken. Each patient suffered small bowel obstruction and at surgery each was found to have a mucinous adenocarcinoma of the ileocecal valve. No evidence of Crohn's disease was found. At pathologic examination some interesting characteristics of the tumors were observed, which perhaps accounted for the misdiagnosis of Crohn's disease. It also was evident that the clinical information supplied to the radiologist may have influenced the radiologic interpretations. These cases stress the importance of obtaining tissue diagnoses in situations where radiographic findings are consistent but atypical with the clinical diagnosis of Crohn's disease.

Adenocarcinoma, Mucinous↗

Subacute ischemia of the colon esophageal interposition.

The most devastating complication of colon interposition is acute ischemia with colon necrosis. Delayed complications of the interposed colon, including long segment stricturing develop in an occasional patient. Some investigators have speculated that these late complications result from delayed colon ischemia. We believe that these patients represent a small subgroup who have nonnecrotic vascular insufficiency (subacute ischemia) of the interposed colon, which is present from the time of the operation. We reviewed the postoperative contrast radiographic studies of 3 patients with subacute colon ischemia. The radiographic findings are characteristic, and are identical to those seen in ischemic colitis of the nonmobilized colon. They include loss of haustral folds, an ill-defined bowel wall border, and mucosal changes such as "thumbprinting," and "urticaria." Fibrosis and stricturing represent the end-stage of the ischemic process.

Acute Disease↗

Prototypical HTLV-I/II infection is rare in LGL leukemia.

The etiology of LGL leukemia is not known; however, we recently detected HTLV-II in a patient with LGL leukemia. In this study, we found that sera from 6 of 28 patients with LGL leukemia were positive for HTLV-I/II using a whole virus ELISA; moreover, the ELISA-negative sera were near the positive cut-off value. Therefore, we performed additional studies on these sera using commercially available assays which can confirm and distinguish HTLV-I from HTLV-II infection. Serum from only one patient was confirmed positive using conventional criteria (HTLV-II+). Sera from 25 patients (89%) had indeterminate reactivity on Western blot assays. Of these, sera from 21 (84%) reacted to gag protein p24; 12 (48%) reacted with recombinant env protein p21e, and 10 (40%) reacted with both. We could not detect HTLV-I/II pol or pX gene sequences in these patients using polymerase chain reaction analyses, with the exception of the HTLV-II-infected patient described previously. These data show that most patients with LGL leukemia are not infected with prototypical HTLV-I or HTLV-II. The frequent reactivity of patient sera to HTLV-I/II gag protein p24 and to env protein p21e, however, suggests that a deleted or variant form of HTLV-I/II may be associated with LGL leukemia.

Blotting, Western↗

The effect of tumour shrinkage on biologically effective dose, and possible implications for fractionated high dose rate brachytherapy.

A method for incorporating a tumour shrinkage factor into linear-quadratic (LQ) brachytherapy equations is proposed. When there is a significant degree of ongoing shrinkage throughout a course of brachytherapy, and when the sources are centrally situated within the tumour volume, the biologically effective dose (BED) to the tumour will be higher than that which is calculated with standard equations. Although the analytical method initially assumes that shrinkage is exponential with time, it is shown that the modified equations (for both high and low dose rate brachytherapy) are essentially analogous to existing BED equations, but with the addition of a simple linear time-dependent factor. In this article, which concentrates on the implications for fractionated high dose-rate brachytherapy, it is demonstrated that increasing the time interval between fractions will only improve the BED in some cases, the conditions for which may be identified in terms of the ratio K/z, where K is the daily dose required to combat tumour repopulation and z is the daily linear shrinkage rate. In the absence of predictive assay techniques, or where there is doubt as to whether or not the radiobiological conditions favour an increase in the interval between each dose delivery, relatively close spacing (i.e. acceleration) of brachytherapy fractions appears to be the most prudent option.

Brachytherapy↗

Psychosis as precipitating trauma for PTSD: a treatment strategy.

Parallels between the experience of living with a psychotic illness and that of PTSD as a response to combat stress are explored, and similarities with respect to a loss of a sense of self are examined. Therapeutic implications of the possible connection between the two disorders are delineated in terms of a three-stage psychosocial recovery model.

Adaptation, Psychological↗

Ivermectin and onchocercal optic neuritis: short-term effects.

In 1982 the macrocyclic lactone, ivermectin, was first tested in human patients with onchocerciasis. It has since undergone phase I to IV trials and is now being widely distributed in onchocercal areas. The previous microfilaricide, diethylcarbamazine citrate (DEC), is known to precipitate or exacerbate active optic neuritis in some onchocercal patients, as part of a wider inflammatory response (the Mazzotti reaction). Ivermectin may also cause a mild reaction, especially in people with high microfilarial loads. Few data are available concerning the effect of ivermectin on active optic neuritis. A large, randomised, double-masked, phase IV trial is reported. Individuals were screened for evidence of optic nerve disease (OND), and those identified as possible cases of OND underwent detailed ophthalmic examination, including fluorescein angiography, before being dosed with ivermectin or placebo. A total of 6831 persons were screened of whom 856 (13%) underwent angiography prior to dosing. At 7-14 days after dosing an attempt was made to re-examine 50% of adults over the age of 20 years, including all those with OND. Six hundred and eighty-eight repeat or new angiograms were performed. During this period, 5 new cases of active optic neuritis and one case of exacerbation of existing optic neuritis were identified. Five of these individuals had received placebo and one ivermectin. Two individuals with optic neuritis before dosing had improved after 7-14 days. One had received placebo, the other ivermectin. Ivermectin does not appear to precipitate or exacerbate optic neuritis at a period of 7-14 days.

Adolescent↗

Alterations in the PITSLRE protein kinase gene complex on chromosome 1p36 in childhood neuroblastoma.

p58cdc2L1, a protein kinase implicated in apoptotic signaling, is one of eight separate kinases encoded by three tandemly duplicated and linked genes, which we have termed PITSLRE A, B and C. One allele of this complex on chromosome 1 was either deleted or translocated in each of 18 neuroblastoma cell lines with cytogenetically apparent 1p alterations. A protein encoded by this locus, PITSLRE gamma 1, was absent in three of the lines and a smaller, apparently truncated, PITSLRE polypeptide was found in another line. These findings identify a novel gene complex on chromosome 1 that encodes a protein kinase subfamily. We suggest that the PITSLRE locus may harbour one or more tumour suppressor genes affected by chromosome 1p36 modifications in neuroblastoma.

Alleles↗

Distribution and aetiology of blindness and visual impairment in mesoendemic onchocercal communities, Kaduna State, Nigeria. Kaduna Collaboration for Research on Onchocerciasis.

During a field trial of ivermectin in Kaduna State, 6831 people age 5 years and above, living in 34 mesoendemic onchocercal communities in Kaduna State, northern Nigeria, were examined for ocular disease. Visual function assessments included tests of visual acuity and visual fields. A total of 185 individuals (2.7%) were bilaterally blind by acuity criteria with a further 28 blind by field constriction. The overall prevalence of blindness was 3.1%. A further 118 individuals were visually impaired by WHO criteria. Examination for the cause of blindness revealed that 43% of eyes in bilaterally blind patients were blind due to onchocerciasis. A further 11% were blind from optic atrophy much of which was probably onchocercal in origin. Glaucoma was the next most common cause of blindness in the bilaterally blind (11%). Only 6% of eyes were blind from cataract as the primary cause. In the visually impaired population cataract was the most common primary cause of impaired/blind eyes (31%), followed by onchocerciasis (19%) [corrected].

Adolescent↗

Crouzon syndrome is not linked to craniosynostosis loci at 7p and 5qter.

Evidence for linkage has been sought, in four pedigrees with Crouzon syndrome, between polymorphic markers known to be linked to the Saethre-Chotzen locus on 7p and another form of autosomal dominant craniosynostosis on 5q. The data we present exclude Crouzon syndrome as an allelic variant at either of these known craniosynostosis loci.

Chromosomes, Human, Pair 5↗

Persistent oral contrast agent lining the intestine in severe mucosal disease: elucidation of radiographic appearance.

Plain radiographs and computed tomographic scans obtained in a severely neutropenic patient with acute lymphoblastic leukemia and cytomegalovirus-associated enterocolitis revealed a pattern of prolonged mucosal adherence of oral contrast agent to the small bowel. This pattern was seen as long as 16 weeks after administration of contrast agent and has been seen previously only in patients who have received bone marrow transplants. Two sets of intestinal biopsy specimens contained crystals that coated denuded mucosa at the site of ulceration and later were trapped within the lamina propria. Electron diffraction and energy-dispersive radiographic analysis showed that these crystals were composed of barium sulfate.

Administration, Oral↗

Selenium in malnourished Sudanese children: status and interaction with clinical features.

Plasma selenium (Se), haemoglobin (Hb) and packed cell volume (PCV) were measured in 53 malnourished Sudanese children, age 6-36 months, and 11 children who had tuberculosis. Twelve healthy well-nourished children served as controls. The mean (+/- SD) plasma Se (mg/kg) was 0.05 (0.036), 0.070 (0.040), 0.063 (0.015), 0.73 (0.012), 0.082 (0.014) in children with kwashiorkor/marasmic kwashiorkor (oedematous group), marasmus, tuberculosis and healthy controls. The mean Se level in the various groups showed a significant difference (p < 0.002). Whereas the oedematous group differed significantly from the rest, there was no difference between the means of the marasmic, underweight, tuberculosis patients and controls. The mean plasma albumin (+/- SD) in oedematous group was 19.6 (6.6) g/l and ranged between 22.6 (5.0) and 33.1 (3.0) in the other groups. A significant positive correlation was found between plasma Se level, albumin, Hb and PCV (respectively, r = 0.46, p < 0.0001; r = 0.37, p < 0.001; r = 0.36, p < 0.002).

Child, Preschool↗

The analysis of binary and categorical data from crossover trials.

A review is presented of methods for the analysis of discrete data from crossover trials. The definition and interpretation of the model for the data is used as a central theme. Distinctions are drawn between different types of model, particularly marginal and subject specific. It is seen how much recent methodology for analysing correlated categorical data can be applied successfully to the crossover setting. The current accessibility of each method is considered and the different approaches are illustrated and compared using two examples.

Bias↗