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J H Williams

Publications and source records attributed to J H Williams.

At least 73 records · Page 4Linked to original sources
PubMed1997

Induction of the heat shock response and translational thermotolerance in day 15 ovine trophectoderm.

The objectives of this study were to determine the ability of trophectoderm from preimplantation ovine embryos to synthesize hsp70 in response to heat shock and to identify conditions which induce translational thermotolerance in this tissue. Day 15 embryos were collected, and proteins synthesized in 1.5-mm sections of trophectoderm were radioactively labeled with (35)S-methionine. One-dimensional SDS-PAGE gels, two-dimensional gel electrophoresis and Western blots were utilized to characterize the heat shock response and to examine the induction of translational thermotolerance. Increased synthesis of the 70 kDa heat shock proteins and a protein with an approximate molecular weight of 15 to 20 kDa was observed with heat shock (> or = 42 degrees C). Total protein synthesis decreased (P < 0.05) with increased intensity of heat shock. At 45 degrees C, protein synthesis was suppressed with little or no synthesis of all proteins including hsp70. Recovery of protein synthesis following a severe heat shock (45 degrees C for 20 min) occurred faster (P < 0.05) in trophectoderm pretreated with a mild heat shock (42 degrees C for 30 min) than trophectoderm not pretreated with mild heat. In summary, trophoblastic tissue obtained from ovine embryos exhibit the characteristic "heatshock" response similar to that described for other mammalian systems. In addition, a sublethal heat shock induced the ability of the tissue to resume protein synthesis following severe heat stress. Since maintaining protein synthesis is crucial to embryonic survival, manipulation of the heat-shock response may provide a method to enhance embryonic survival.

Journal Article↗
PubMed1997

Lyn tyrosine kinase is essential for erythropoietin-induced differentiation of J2E erythroid cells.

Erythropoietin stimulates the immature erythroid J2E cell line to terminally differentiate and maintains the viability of the cells in the absence of serum. In contrast, a mutant J2E clone (J2E-NR) fails to mature in response to erythropoietin; however, it remains viable in the presence of the hormone. We have shown previously that intracellular signalling is disrupted in the J2E-NR cell line and that tyrosine phosphorylation is dramatically reduced after erythropoietin stimulation. In this study we investigated the defect in J2E-NR cells that is responsible for their inability to differentiate. Screening of numerous signalling molecules revealed that the lyn tyrosine kinase appeared to be absent from J2E-NR cells. On closer examination, both lyn mRNA and protein content were reduced >500-fold. Consistent with a defect in lyn, amphotropic retroviral infection of J2E-NR cells with lyn restored the ability of the cells to synthesize haemoglobin and enabled the cells to mature morphologically. Conversely, the ability of J2E cells to differentiate in response to epo was severely curtailed when antisense lyn oligonucleotides or a dominant negative lyn were introduced into the cells. However, erythropoietin-supported viability was unaffected by reducing lyn activity. The ability of two other erythropoietin-responsive cell lines (R11 and R24) to differentiate in response to the hormone was also reduced by dominant negative lyn. Finally, co-immunoprecipitation and yeast two-hybrid analyses indicated that lyn directly associated with the erythropoietin receptor complex. These data indicate for the first time an essential role for lyn in erythropoietin-initiated differentiation of J2E cells but not in the maintenance of cell viability.

Animals↗
PubMed1997

Haloperidol enhances latent inhibition in visual tasks in healthy people.

We have previously shown that 0.5 mg haloperidol (i.v.) increased latent inhibition in one of two visual tasks. The present study analysed the effects of a higher dose of haloperidol (1.0 mg, i.v.) on latent inhibition in these two visual tasks in healthy volunteers in a randomised controlled trial. In the task where 0.5 mg haloperidol had enhanced latent inhibition, 1.0 mg had the same effect, thus replicating the previous result. In the task where 0.5 mg haloperidol had been ineffective, 1.0 mg haloperidol enhanced latent inhibition in high schizotypal subjects only. This indicates that subjects with higher schizotypy scores are more sensitive to dopamine blockade. A comparison of the results from the studies at the two different doses suggests a dose dependence of haloperidol's effects on latent inhibition that parallels results from animal work.

Adult↗
PubMed1997

Immunohistochemical phenotype of malignant mesothelioma: predictive value of CA125 and HBME-1 expression.

Histological diagnosis of malignant mesothelioma and differentiation from adenocarcinoma is often difficult. Definitive pathological confirmation of malignant mesothelioma requires demonstration of an appropriate immunohistochemical phenotype. Selection of an optimum panel of immunohistochemical antibodies for the reliable identification of malignant mesothelioma is hindered by the absence of a specific immunohistochemical label for mesothelioma cells. Recently, we have found that the ovarian carcinoma cell antibody CA125 labels malignant mesothelioma cells, and the antibody HBME-1 has been developed as a sensitive mesothelial cell marker. We have compared the immunohistochemical staining patterns achieved with CA125 and HBME-1 to those obtained using a panel of eight further antibodies in 17 malignant mesotheliomas and 14 primary and secondary adenocarcinomas within lung and pleura. CA125 labelled malignant mesothelioma cells in 15 of 17 cases (88%), and adenocarcinoma cells in seven of 14 cases (50%). HBME-1 labelled mesothelioma cells in all 17 cases (100%) but also labelled adenocarcinoma cells in 10 of 14 cases (71%). BerEP4 positively labelled one malignant mesothelioma but was negative in the remaining 16 cases and positively labelled nine of 14 adenocarcinomas (64%). Monoclonal anti-CEA, AUA-1, CA19.9 and LeuM1 labelled no malignant mesotheliomas and were positive in 10 (71%), nine (64%), eight (57%) and six (43%) of 14 cases of adenocarcinoma, respectively. Diastase-PAS staining detected neutral mucin in none of the malignant mesotheliomas but in 10 (71%) of the 14 adenocarcinomas. We conclude that CA125 and HBME-1 do not label mesothelial cells with sufficient specificity to be useful for differentiating malignant mesothelioma from adenocarcinoma, although negative staining with HBME-1 makes a diagnosis of malignant mesothelioma unlikely. As there remains an absence of a specific positive mesothelial cell marker this distinction is still most reliably made using a panel of antibodies including at least two of the following: anti-CEA, AUA-1, BerEP4, LeuM1 and CA19.9, in combination with histochemical assessment of neutral mucin production.

Adenocarcinoma↗
PubMed1997

Tissue preparation for immunocytochemistry.

AIMS: To investigate the effect of tissue preparation on immunostaining and to establish whether there is a standard tissue preparation schedule that allows optimal demonstration of all antigens. METHODS: Blocks of tonsil were subjected to variations to a standard fixation, processing, and section preparation schedule. The sections were stained with five antibodies-L26 (CD20), UCHL1 (CD45RO), CD3, vimentin, and anti-kappa light chain--using the streptavidinbiotin immunostaining technique. When further investigation was necessary, other tissues and antibodies were used and where weak immunostaining was obtained the use of microwave pretreatment to improve staining was tested. RESULTS: Several factors involved in fixation were found to affect immunoreactivity. These included the duration, pH, and type of fixative used. In tissue processing only temperature and the duration of the dehydration and wax infiltration steps affected immunoreactivity. Of all the factors investigated, the temperature and duration of the section drying had the greatest effect. In contrast, long term storage of cut sections before immunostaining had no effect on the reactivity of the antibodies tested. Antibodies were found to be affected by alterations to tissue preparation by varying degrees, UCHL1 and vimentin being the most susceptible to changes in fixation and L26 to changes in processing. Where weak staining occurred, microwave pretreatment was generally found to eliminate the problem. CONCLUSIONS: There is no standard tissue preparation schedule for the optimal demonstration of all antigens. Factors involved in all aspects of tissue preparation can affect immunoreactivity, so it is important that precise details of the preparation schedule are given when reporting immunocytochemical studies, rather than using the general term "routinely fixed and processed".

Histocytological Preparation Techniques↗
PubMed1997

Contractile apparatus and sarcoplasmic reticulum function: effects of fatigue, recovery, and elevated Ca2+.

This investigation tested the notion that fatiguing stimulation induces intrinsic changes in the contractile apparatus and sarcoplasmic reticulum (SR) and that these changes are initiated by elevated intracellular Ca2+ concentration ([Ca2+]i). Immediately after stimulation of frog semitendinosus muscle, contractile apparatus and SR function were measured. Despite a large decline in tetanic force (Po), maximal Ca2+-activated force (Fmax) of the contractile apparatus was not significantly altered. However, Ca2+ sensitivity was increased. In conjunction, the rate constant of Ca2+ uptake by the SR was diminished, and the caffeine sensitivity of Ca2+ release was decreased. During recovery, Po, contractile apparatus, and SR function each returned to near-initial levels. Exposure of skinned fibers to 0.5 microM free Ca2+ for 5 min depressed both Fmax and Ca2+ sensitivity of the contractile apparatus. In addition, caffeine sensitivity of Ca2+ release was diminished. Results suggest that fatigue induces intrinsic alterations in contractile apparatus and SR function. Changes in contractile apparatus function do not appear to be mediated by increased [Ca2+]i. However, a portion of the change in SR Ca2+ release seems to be due to elevated [Ca2+]i.

Animals↗
PubMed1997

Properties of carbachol-induced oscillatory activity in rat hippocampus.

Properties of carbachol-induced oscillatory activity in rat hippocampus. J. Neurophysiol. 78: 2631-2640, 1997. The recent resurgence of interest in carbachol oscillations as an in vitro model of theta rhythm in the hippocampus prompted us to evaluate the circuit mechanisms involved. In extracellular recordings, a regularly spaced bursting pattern of field potentials was observed in both CA3 and CA1 subfields in the presence of carbachol. Removal of the CA3 region abolished oscillatory activity observed in CA1, suggesting that the oscillatory generator is located in CA3. An alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), blocked carbachol oscillations, indicating that AMPA receptor-mediated synaptic currents are necessary for the population oscillation. Moreover, the spread of oscillatory activity into CA1 required intact N-methyl--aspartate receptors. These data are more consistent with epileptiform bursting than with theta rhythm described in vivo. In the presence of carbachol, individual CA3 pyramidal cells exhibited a slow, rhythmic intrinsic oscillation that was not blocked by DNQX and that was enhanced by membrane hyperpolarization. We hypothesize that this slower oscillation is the fundamental oscillator that participates in triggering the population oscillation by exciting multiple synaptically connected CA3 neurons. gamma-aminobutyric acid-A (GABAA) receptors are not necessary for carbachol to elicit synchronous CA3 field events but are essential to the bursting pattern observed. Neither GABAB nor metabotropic glutamate receptors appear to be necessary for carbachol oscillations. However, both nicotinic and M1 and M3 muscarinic cholinergic receptors contribute to the generation of this activity. These results establish the local circuit elements and neurotransmitter receptors that contribute to carbachol-induced oscillations and indicate that carbachol-induced oscillations are fundamentally distinct from theta rhythm in vivo.

2-Amino-5-phosphonovalerate↗
PubMed1997

Skeletal muscle sarcoplasmic reticulum Ca(2+)-ATPase gene expression in congestive heart failure.

Congestive heart failure leads to skeletal muscle abnormalities, one of which is a prolongation of sarcoplasmic reticulum Ca2+ flux. The purpose of this study was to determine whether skeletal muscle of spontaneous hypertensive and heart failure rats have alterations in the expression of the sarcoplasmic (or endoplasmic) reticulum Ca(2+)-ATPase (SERCA) gene. Northern analysis revealed that SERCA1, the predominant skeletal muscle isoform, was decreased by 45%, 43%, and 58% in the tibialis anterior, plantaris, and diaphragm muscles, respectively. Ribonuclease protection assay showed that the decrease was due to the adult isoform, SERCA1a, with minor changes in the alternatively spliced neonatal isoform, SERCA1b. There was no change in SERCA1 mRNA levels in gastrocnemius muscles. No change was found in SERCA2a (cardiac/slow skeletal isoform) mRNA or protein levels or in SERCA2b (smooth muscle isoform), dihydropyridine receptor, or alpha-actin mRNA levels in diaphragm muscle. Northern blot and ribonuclease protection assays showed that SERCA2a decreased 61% in the heart while the alternatively spliced isoform, SERCA2b, decreased 27%. Western analysis of the tibialis anterior, diaphragm, and gastrocnemius muscles showed a decrease in SERCA1 protein levels by 46%, 64%, and 42%, respectively, whereas sarcoplasmic reticulum Ca(2+)-ATPase activity, a functional correlate of SERCA expression, was decreased by 38%, 38%, and 40% in the same muscles, SERCA2 protein expression decreased by 36% in the failing heart. Decreases in both mRNA and protein suggest pretranslational control of SERCA1 expression, whereas the lack of decreased SERCA1 mRNA in gastrocnemius muscle suggests translational regulation. The decreased SERCA1 protein expression in all muscles studied probably contributes to contractile abnormalities related to excitation-contraction coupling function in heart failure.

Animals↗
PubMed1997

Intravenous administration of haloperidol to healthy volunteers: lack of subjective effects but clear objective effects.

Healthy volunteers who received i.v. injections of either saline or haloperidol (0.5 or 1.0 mg) made visual analogue scale ratings of subjective mood, tension, shakiness and the global feeling of having received an active drug. The subjective ratings of volunteers who received haloperidol did not differ, overall, from those who received saline. In contrast, the drug caused clear objective changes in several psychological tests. I.v. administration of low doses of haloperidol may permit double-blind testing of the psychological actions of haloperidol in healthy volunteers.

Affect↗
PubMed1997

Time course of response to electroconvulsive therapy in elderly depressed subjects.

OBJECTIVE: To assess the time course of response to electroconvulsive therapy (ECT) in elderly depressed subjects. In particular, to determine whether significant antidepressant response occurs during the first few treatments. DESIGN: A naturalistic study of elderly patients receiving ECT. SETTING: Acute admission wards of a UK old age psychiatric service. PATIENTS: 13 consecutive inpatients aged over 65 years, meeting inclusion criteria, with a diagnosis of current major depressive episode, who were treated with ECT. MAIN OUTCOME MEASURES: Severity of depression as assessed by the Montgomery and Asberg Depression Rating Scale (MADRS), psychomotor speed as assessed by Gibson's spiral maze test (GSM) and the Kendrick digit copying test (KDCT). RESULTS: The first ECT treatment reduced the mean MADRS score by 21% (p < 0.0001) and the second treatment the mean MADRS was reduced by 36% (p < 0.0001). A non-significant improvement on GSM scores was seen that paralleled improvement in the MADRS. The average number of ECT treatments needed to reduce the MADRS score by half was 3.73 +/- 1.85, though the actual number varied between 1 and 7. CONCLUSIONS: ECT is a highly effective treatment for depression in the elderly and significant antidepressant response can be demonstrated after only one treatment, arguing for careful mental state monitoring during treatment. However, considerable variability is seen in individual cases, implying that ECT should not be abandoned just because rapid response is not seen.

Aged↗
PubMed1996

Antipsychotic drug effects in a model of schizophrenic attentional disorder: a randomized controlled trial of the effects of haloperidol on latent inhibition in healthy people.

We studied the effects of haloperidol (0.5 mg, intravenously) on latent inhibition in an auditory paradigm and two visual paradigms in healthy subjects. Haloperidol increased latent inhibition in one visual paradigm and tended to increase latent inhibition in an auditory task, compared to saline-injected controls. These results indicate that haloperidol can enhance the selectivity of attention. In contrast, previous studies have reported that acute schizophrenics show reduced latent inhibition.

Acoustic Stimulation↗
PubMed1996

Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial.

BACKGROUND: Evidence has accumulated from observational studies that people eating more fruits and vegetables, which are rich in beta-carotene (a violet to yellow plant pigment that acts as an antioxidant and can be converted to vitamin A by enzymes in the intestinal wall and liver) and retinol (an alcohol chemical form of vitamin A), and people having higher serum beta-carotene concentrations had lower rates of lung cancer. The Beta-Carotene and Retinol Efficacy Trial (CARET) tested the combination of 30 mg beta-carotene and 25,000 IU retinyl palmitate (vitamin A) taken daily against placebo in 18314 men and women at high risk of developing lung cancer. The CARET intervention was stopped 21 months early because of clear evidence of no benefit and substantial evidence of possible harm; there were 28% more lung cancers and 17% more deaths in the active intervention group (active = the daily combination of 30 mg beta-carotene and 25,000 IU retinyl palmitate). Promptly after the January 18, 1996, announcement that the CARET active intervention had been stopped, we published preliminary findings from CARET regarding cancer, heart disease, and total mortality. PURPOSE: We present for the first time results based on the pre-specified analytic method, details about risk factors for lung cancer, and analyses of subgroups and of factors that possibly influence response to the intervention. METHODS: CARET was a randomized, double-blinded, placebo-controlled chemoprevention trial, initiated with a pilot phase and then expanded 10-fold at six study centers. Cigarette smoking history and status and alcohol intake were assessed through participant self-report. Serum was collected from the participants at base line and periodically after randomization and was analyzed for beta-carotene concentration. An Endpoints Review Committee evaluated endpoint reports, including pathologic review of tissue specimens. The primary analysis is a stratified logrank test for intervention arm differences in lung cancer incidence, with weighting linearly to hypothesized full effect at 24 months after randomization. Relative risks (RRs) were estimated by use of Cox regression models; tests were performed for quantitative and qualitative interactions between the intervention and smoking status or alcohol intake. O'Brien-Fleming boundaries were used for stopping criteria at interim analyses. Statistical significance was set at the .05 alpha value, and all P values were derived from two-sided statistical tests. RESULTS: According to CARET's pre-specified analysis, there was an RR of 1.36 (95% confidence interval [CI] = 1.07-1.73; P = .01) for weighted lung cancer incidence for the active intervention group compared with the placebo group, and RR = 1.59 (95% CI = 1.13-2.23; P = .01) for weighted lung cancer mortality. All subgroups, except former smokers, had a point estimate of RR of 1.10 or greater for lung cancer. There are suggestions of associations of the excess lung cancer incidence with the highest quartile of alcohol intake (RR = 1.99; 95% CI = 1.28-3.09; test for heterogeneity of RR among quartiles of alcohol intake has P = .01, unadjusted for multiple comparisons) and with large-cell histology (RR = 1.89; 95% CI = 1.09-3.26; test for heterogeneity among histologic categories has P = .35), but not with base-line serum beta-carotene concentrations. CONCLUSIONS: CARET participants receiving the combination of beta-carotene and vitamin A had no chemopreventive benefit and had excess lung cancer incidence and mortality. The results are highly consistent with those found for beta-carotene in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study in 29133 male smokers in Finland.

Anticarcinogenic Agents↗
PubMed1996

Production of murine monoclonal antibodies against sulcofuron and flucofuron by in vitro immunisation.

Monoclonal murine anti-pesticide antibodies were produced by in vitro immunisation (IVI) of cultured splenocytes with the pesticides sulcofuron and flucofuron. The majority of both anti-flucofuron and anti-sulcofuron antibodies obtained were of the IgM isotype, rather than IgG. When used in an indirect enzyme-linked immunosorbent assay (ELISA), the antibodies bound to plate coating antigens which incorporated haptens that mimicked moieties present within the immunising pesticide. The antibodies exhibited a high degree of specificity, with the degree of cross-reactivity related to the structural similarity between the hapten present in the plate coating antigen and the moieties present within the immunising pesticide. These results indicated that antibodies specific to both sulcofuron and flucofuron had been produced by IVI. Synthesis of both hapten analogues and immunogens as required for methods based on in vivo immunisation was avoided, whilst antibody production was also comparatively more rapid than traditional methods and minimised animal discomfort.

Animals↗
PubMed1996

Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease.

BACKGROUND: Lung cancer and cardiovascular disease are major causes of death in the United States. It has been proposed that carotenoids and retinoids are agents that may prevent these disorders. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled primary prevention trial -- the Beta Carotene and Retinol Efficacy Trial -- involving a total of 18,314 smokers, former smokers, and workers exposed to asbestos. The effects of a combination of 30 mg of beta carotene per day and 25,000 IU of retinol (vitamin A) in the form of retinyl palmitate per day on the primary end point, the incidence of lung cancer, were compared with those of placebo. RESULTS: A total of 388 new cases of lung cancer were diagnosed during the 73,135 person-years of follow-up (mean length of follow-up, 4.0 years). The active-treatment group had a relative risk of lung cancer of 1.28 (95 percent confidence interval, 1.04 to 1.57; P=0.02), as compared with the placebo group. There were no statistically significant differences in the risks of other types of cancer. In the active-treatment group, the relative risk of death from any cause was 1.17 (95 percent confidence interval, 1.03 to 1.33); of death from lung cancer, 1.46 (95 percent confidence interval, 1.07 to 2.00); and of death from cardiovascular disease, 1.26 (95 percent confidence interval, 0.99 to 1.61). On the basis of these findings, the randomized trial was stopped 21 months earlier than planned; follow-up will continue for another 5 years. CONCLUSIONS: After an average of four years of supplementation, the combination of beta carotene and vitamin A had no benefit and may have had an adverse effect on the incidence of lung cancer and on the risk of death from lung cancer, cardiovascular disease, and any cause in smokers and workers exposed to asbestos.

Aged↗
PubMed1996

Retrograde messengers and long-term potentiation: a progress report.

Long term potentiation (LTP) is a widely studied form of synaptic plasticity. Brief tetanic stimulation of synaptic afferents in several areas of the brain, most notably the hippocampus, produces long lasting changes in the synaptic strength. The induction of LTP requires in the limit a significant activation of the NMDA receptor and the subsequent entry of calcium into the post synaptic cell. The maintenance of LTP requires at least in part a change in presynaptic function. This review addresses the current thinking in the literature on how a post synaptic induction event may be communicated to the presynaptic terminal and subsequently lead to a series of poorly defined biochemical process that ultimately lead to an enhancement in the efficiency of the potentiated terminal.

Animals↗
PubMed1996

Transitional cell carcinoma of the kidney with tumor thrombus into the vena cava.

Transitional cell carcinoma of the upper urinary tract with inferior vena cava tumor thrombus is an unusual entity. We report the 16th such case and review the previous cases in the world literature. Preoperative diagnosis was correct in only 5 of the cases. This type of condition can be easily presumed to be renal cell carcinoma. Fifteen of the cases were managed with radical nephrectomy; 8 patients were managed with partial or complete resection of the vena cava due to adherence of the tumor thrombus to the vessel wall. Overall outcome was poor, with short postoperative survival. Correct preoperative diagnosis, although difficult, could allow more complete preoperative planning or appropriate nonoperative management.

Aged↗