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P Roberts

Publications and source records attributed to P Roberts.

At least 91 records · Page 5Linked to original sources
PubMed1997

The use of fluorescent in situ hybridization for detection of the t(2;5)(p23;q35) translocation in anaplastic large-cell lymphoma.

BACKGROUND: Anaplastic large-cell lymphoma (ALCL) is a recently recognized, distinctive type of non-Hodgkin's lymphoma characterized by anaplastic large-cell cytology and expression of a member of the TNF-receptor family CD30. A characteristic chromosomal translocation has been identified in ALCL of T-or null-cell lineage which juxtaposes a novel tyrosine kinase (anaplastic lymphoma kinase, ALK) located at 2p23 with the nucleophosmin gene (NPM) at 5q35. A chimeric mRNA transcript is produced, and the translocation results in constitutive expression of a truncated form of the ALK protein, p80. There is controversy concerning whether or not the translocation occurs in Hodgkin's disease. The aim of this study was to develop a methodology for fluorescent in situ hybridization (FISH) to detect the t(2;5)(p23;q35), and to compare the results with conventional cytogenetics, reverse-transcriptase PCR and immunostaining for the p80 protein. PATIENTS AND METHODS: Twenty-five cases of malignant lymphoma (11 ALCL and 14 HD) were studied. Immunohistochemistry was performed to confirm the diagnosis and for analysis of p80 expression. Conventional cytogenetics were analyzed on G-banded metaphase spreads. FISH was performed using whole chromosome paints for chromosomes 2 and 5 on metaphase spreads and YAC probes for interphase nuclei. Reverse-transcriptase PCR using primers for ALK and NPM was used to amplify the translocation breakpoint in extracted mRNA. RESULTS: Among 11 cases of ALCL examined by FISH, the translocation was detected in 4. Two of these cases also had RT-PCR and p80 staining performed, with positive results. Among 7 cases where the t(2;5) was not detected by FISH, 3 cases were examined by RT-PCR with negative results and 4 cases by p80 staining, also negative. The RT-PCR was negative in all 14 cases of Hodgkin's disease, 4 of which were also examined by FISH and found to be negative. CONCLUSION: Fluorescent in situ hybridization is a useful method for detection of the t(2;5)(p23;q35) in anaplastic large-cell lymphoma. The results concur with those of RT-PCR for the chimeric transcript and immunostaining for the p80 protein. The frequency with which the translocation was found was 36% in this small series, and no evidence of the translocation was found in cases of Hodgkin's disease.

Antigens, Neoplasm↗
PubMed1997

Promiscuous translocations of chromosome arm 17q in human neuroblastomas.

Deletions of chromosome arm 1p and amplification of the MYCN oncogene are well-recognized genetic changes in neuroblastoma cells. Technical difficulties in cytogenetic analysis of this tumour have hampered the recognition of other recurring abnormalities, but recent use of molecular cytogenetic techniques has indicated significant involvement of chromosome arm 17q. In primary tumours and in cell lines, a recurrent unbalanced translocation t(1p;17q) has been identified by fluorescence in situ hybridization. We confirm the occurrence of this translocation in primary tumours and, in addition, we describe seven new structural rearrangements all of which result in gain of 17q in tumour cells. These rearrangements involved chromosome arms 9p, 10q, 11p, 14q, and 16q. Triplication of the 17q arm was seen in one case. The 17q breakpoint was most commonly q21. All these 17q changes were found in near-diploid tumours. We have also reviewed the literature for neuroblastoma karyotypes involving 17q abnormalities; taken in conjunction with our findings this indicates a remarkable promiscuity of translocation partners, with more than 20 different chromosome regions involved in 17q translocations.

Bone Marrow Neoplasms↗
PubMed1997

Infection with Plasmodium berghei alters benzodiazepine receptor in rat brain.

The purpose of this study was to assess the effect of malaria infection on benzodiazepine binding in rat brain. Young male Wistar rats were infected with the rodent parasite Plasmodium berghei, while age-matched control rats (n = 5) received normal saline intraperitoneally. Parasitemia was determined in blood of infected animals. Animals were killed after two weeks, and synaptosomal brain membrane homogenate was prepared from cerebral cortex. Membrane homogenate was incubated in duplicate with 3H-flunitrazepam (0.2-10 nM in buffer, pH 7.4) and binding parameters determined. The number of receptors (Bmax) was decreased marginally but significantly (P = 0.047) in malaria-infected (MI) rats (MI rats: 1.12 +/- 0.1 pmol.mg-1 protein; control rats: 1.42 +/- 0.08 pmol.mg-1 protein) while binding affinity (Kd) was not altered (MI rats: 1.18 +/- 0.3 nM; control rats: 1.02 +/- 0.15 nM). These results suggest that malaria may be associated with decreased benzodiazepine activity.

Animals↗
PubMed1996

Successfully treated invasive pulmonary aspergillosis associated with smoking marijuana in a renal transplant recipient.

Invasive pulmonary aspergillosis (IPA) is often a lethal entity in transplant recipients (up to 90%). We report the successful treatment of a case of IPA in a renal transplant recipient whose only risk for exposure was habitual marijuana smoking. Although marijuana smoking has been linked to the development of IPA in patients immunosuppressed for a variety of reasons, this case is the first report involving a solid organ transplant recipient. The patient's clinical course and treatment are described and the literature is reviewed with respect to environmental and patient risk factors. In this case, IPA was associated with the patient's heavy usage of marijuana during the immediate posttransplant period. Treatment was successful and included the experimental amphotericin product amphotericin B colloidal dispersion. Contemporaneous exposure to a large amount of inocula of Aspergillus within 30 days of receiving high doses of steroids appeared to be the most important factor that predisposed this patient to IPA. Transplant recipients should be specifically proscribed from marijuana use during periods of high steroid administration.

Antifungal Agents↗
PubMed1996

Chance for choice.

Explore the source record for details and available documents.

Delivery of Health Care↗
PubMed1996

Pre-operative serum levels of CA 242 and CEA predict outcome in colorectal cancer.

The prognostic value of the preoperative serum levels of CA 242 and CEA in patients with colorectal cancer was investigated. The serum concentrations of CA 242 and CEA were determined from preoperative serum samples of 259 patients with colorectal cancer (39 Dukes' A, 100 Dukes' B, 59 Dukes' C and 61 Dukes' D). Survival data of these patients were obtained to the end of 1993. There was a significantly longer survival in patients with a CA 242 level below 20 U/ml compared with patients with an elevated serum level. A difference was seen in overall survival (P < 0.0001), and in Dukes' B (P = 0.016) and Dukes' D (P = 0.009) stages. In Dukes' A and C colorectal cancer, the difference was not significant (P = 0.67 and P = 0.07, respectively). When 5 ng/ml was used as cut-off value for CEA, there was a significant difference in overall survival (P < 0.0001), but not within the different Dukes' stages. The prognosis was considerably worse in patients with concomitant elevation of CA 242 and CEA, compared with the prognosis of patients with normal levels or only one marker elevated (P < 0.0001). When analysing according to stage, a significant difference was seen in Dukes' B (P = 0.0004) and Dukes' C (P = 0.0007) stages. In a multivariate analysis, CA 242 was an independent prognostic factor (P < 0.0001). CEA was also an independent prognostic factor (P = 0.03), but only after exclusion of CA 242. Concomitant rise of CA 242 and CEA was found to be a strong independent prognostic factor (P < 0.0001). This study shows that the pre-operative serum CA 242 level is an independent prognostic factor in patients with colorectal cancer and that the prognosis of patients having a concomitant pre-operative elevation of CA 242 and CEA is poor.

Adult↗
PubMed1996

In vivo nuclear transport kinetics in Saccharomyces cerevisiae: a role for heat shock protein 70 during targeting and translocation.

The transport of proteins into the nucleus is a receptor-mediated process that is likely to involve between 50-100 gene products, including many that comprise the nuclear pore complex. We have developed an assay in Saccharomyces cerevisiae for the nuclear transport of green fluorescent protein fused to the SV-40 large T antigen nuclear localization signal (NLS-GFP). This assay allows the measurement of relative NLS-GFP nuclear import rates in wild-type and mutant cells under various physiological conditions. Probably the best understood component of the nuclear transport apparatus is Srp1p, the NLS receptor, which binds NLS-cargo in the cytoplasm and accompanies it into the nucleus. When compared to SRP1+ cells, NLS-GFP import rates in temperature-sensitive srp1-31 cells were slower and showed a lower temperature optimum. The in vivo transport defect of the srp1-31 cells was correlated with the purified protein's thermal sensitivity, as assayed by in vitro NLS peptide binding. We show that the kinetics of NLS-directed nuclear transport in wild-type cells is stimulated by the elevated expression of SSA1, which encodes a cytoplasmic heat shock protein 70 (Hsp70). Elevated Hsp70 levels are sufficient to suppress the NLS-GFP import defects in srp1-31 and nup82-3 cells. NUP82 encodes a protein that functions within the nuclear pore complex subsequent to docking. These results provide genetic evidence that Hsp70 acts during both targeting and translocation phases of nuclear transport, possibly as a molecular chaperone to promote the formation and stability of the Srp1p-NLS-cargo complex.

Antigens, Viral, Tumor↗
PubMed1996

Long-term isoprenaline administration and its effect on the revascularisation and regeneration of skeletal muscle transplants in mice.

The long-term administration of the beta 2-agonist isoprenaline (at 2 dosages: 100 micrograms/kg or 300 micrograms/kg) was investigated for its effect on the revascularisation and regeneration of skeletal muscle transplants in mice, and also to determine if there was a dose dependent effect. Morphometric, histological and autoradiographic techniques were employed for the investigation. It was found that the accelerated revascularisation observed in a previous short-term study on the effects of isoprenaline did not occur in longer-term usage (as evidenced by autoradiographic and histological results). However, in the present study, the numbers of presumptive satellite cells (identified by autoradiographic examination) were increased at both dosages in the isoprenaline-treated mice. Significant differences were seen in a number of the parameters examined morphometrically, both between the 2 groups which received isoprenaline, and between these groups and the controls (particularly in the volume of regenerated muscle). Dose dependency was therefore evident between the 2 isoprenaline doses and it was concluded that the increased volume of regenerated muscle seen in these transplants was due to the hypertrophic effect of isoprenaline.

Adrenergic beta-Agonists↗
PubMed1996

Audit of the care of patients with epilepsy in general practice.

BACKGROUND: Previous studies have shown that there is great potential for improving the management of patients with epilepsy. AIM: To identify all patients with epilepsy, to evaluate and audit their care in relation to an annual review, to document seizure frequency and appropriateness of daily therapy to aid compliance and to propose strategies to improve these and other aspects of epileptic care. METHOD: An audit of the care of patients with epilepsy was undertaken in two King's Lynn practices with a combined population of 22,500. Principles for the management of epilepsy were established. From these principles, the following standards were agreed: 75% of patients on treatment for epilepsy should be seen every year, 75% of patients should have their seizure frequency documented, and 75% of patients should take their anti-epileptic drugs no more than twice daily. As a result of the first audit cycle, changes were made in the documentation and advice regarding treatment relating to these standards. RESULTS: The first audit cycle showed that 83% of patients had been seen at least once in the previous year, that documentation of seizure frequency existed for 51% of patients in the past year, and that 63% of patients were taking their treatment no more than twice daily. The evaluation was repeated 22 months later and an overall improvement was demonstrated in the first two results: 95% of patients had been seen in the past year, 93% had had their seizure frequency documented; however, only 66% of patients were taking their treatment twice daily or less. CONCLUSION: Call and recall, and documentation of seizure frequency were improved by this clinical audit. However, alterations in daily therapy appeared difficult for a variety of reasons; for example, therapy might have been initiated by a hospital specialist, and patients in a stable condition might have been apprehensive about changes. In order to improve the care of patients with epilepsy, a primary care team approach is desirable within a structure of good specialist services.

Anticonvulsants↗
PubMed1996

Collection of seasonally spermatozoa-rich semen by electroejaculation of laboratory woodchucks (Marmota monax), with and without removal of bulbourethral glands.

Male woodchucks were subjected to electroejaculation during the early- or mid-breeding season by a commercial stimulator and rectal probe (1.3 x 13 cm, with longitudinal electrode strips on one side) with electrodes oriented ventrally. A study of the voltage and stimulation parameters at a probe depth of 4 to 9 cm suggested that a series of 15 to 75 3-sec pulses of 3 to 6 V each could result in ejaculation and collection of semen. Pulses of only 1 to 2 V frequently caused erection but not ejaculation. Trials conducted on 12 bulbourethral (Cowper's) gland-intact males (n = 18 trials) versus six males from which Cowper's glands had been surgically removed (n = 18 trials) identified these glands as the source of urethral plugs in 77% of ejaculates from the gland-intact males and presumably the source of copulation plugs obtained from the vagina of female woodchucks. The fluid portion of ejaculates from both groups contained few or no spermatozoa. An additional 32 trials were conducted on 12 gland-intact males and eight males without Cowper's glands. These trials included 16 shallow (5 to 8 cm) versus 16 deep (10 to 13 cm) placements of the tip of the rectal probe in each group of males. In gland-intact males the stimulation of sacral (shallow) elements routinely resulted in the emission of large (200 to 300 microl) urethral plugs and fluid volume of 40 to 400 microl, containing few or no spermatozoa. In males without Cowper's glands the sacral stimulation typically produced volumes of 60 to 350 microl of noncoagulating liquid without urethral plugs, containing few or no spermatozoa. Lumbar (deep) stimulation in both groups of males usually resulted in fluid ejaculates, with 60% containing numerous spermatozoa (typically, 0.5 to 3 x 10(6)/ejaculate). Lumbar stimulation usually produced urethral plugs of little (50 to 100 microl) or no volume in gland-intact males and no urethral plugs in males without Cowper's glands. Ejaculates did not coagulate during handling or storage for 4 to 24 h. Serial lumbar stimulation of six males at 2- to 3-week intervals resulted in few spermatozoa, except for a 4- to 8-week period during which > or =0.25 x 10(6) spermatozoa/ejaculate and peaks of 5.3 +/- 2.4 x 10(6) spermatozoa/ejaculate were obtained. The results suggest that electroejaculation can be used to obtain spermatozoa-containing liquid that might be useful for semen evaluation or artificial insemination in laboratory woodchucks, that Cowper's glands are the source of urethral plugs in the ejaculates of this species, and that the fertile period of the male breeding season is limited to 4 to 8 weeks.

Animals↗
PubMed1995

Practice parameters for sigmoid diverticulitis. The Standards Task Force American Society of Colon and Rectal Surgeons.

It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Acute Disease↗
PubMed1995

Loss of cyclin-dependent kinase inhibitor genes and chromosome 9 karyotypic abnormalities in human bladder cancer cell lines.

Loss of cell cycle control through the structural or functional aberration of checkpoint genes and their products is a potentially important process in carcinogenesis. In this study, a panel of well-characterised established human bladder cancer cell lines was screened by the polymerase chain reaction for homozygous loss of the cyclin-dependent kinase inhibitor genes p15, p16 and p27. The results demonstrate that, whereas there was no genetic loss of p27, homozygous deletion of both p15 and p16 genes occurred in seven of 13 (54%) independent bladder cell lines tested. Differential loss of either the p15 or p16 gene was not seen. The p15 and p16 genes are known to be juxtaposed on chromosome 9p21 at the locus of a putative tumour-suppressor gene involved in the initiation of bladder cancer. Cytogenetic analysis of the cell lines revealed karyotypes ranging from near diploid to near pentaploid with complex rearrangements of some chromosomes and a high prevalence of chromosome 9p rearrangements, although all cell lines contained at least one cytogenetically normal 9p21 region. These observations support a role for p15/p16 gene inactivation in bladder carcinogenesis and/or the promotion of cell growth in vitro and lend support to the hypothesis that homozygous deletion centred on 9p21 is a mechanism by which both p15 and p16 genes are co-inactivated.

Base Sequence↗
PubMed1995

Friends in passing: social interaction at an adult day care center.

This study explores the social interactions and friendships that exist among cognitively impaired adult day care participants. A five month participant observation of an adult day care center was conducted, involving fifty-three clients ranging in age from sixty-six to ninety-three. Findings indicate that the clients engage in a variety of social interactions and friendships, enabling them to maintain a sense of self as well as to adjust to the norms of the group. Specific areas to be discussed are: general socializing, enduring friendships, helping relationships and client integration. A descriptive approach such as this provides the opportunity to examine the complexity of social interactions, including the positive relationships available to the cognitively impaired elderly.

Aged↗