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Coup A, Williamson JM, Curley JW. Septal, widely infiltrative and clinically occult adenoid cystic carcinoma of the parotid gland. J Laryngol Otol 1997; 111:491-2. [PMID: 9205619 DOI: 10.1017/s0022215100137739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Most salivary gland tumours present with an obvious mass and are usually diagnosed clinically. We present a case of occult adenoid cystic carcinoma of the parotid which, due to its peculiar septal pattern of growth and complicated clinical setting, defied diagnosis for several years.
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Nakajima A, Hirano M, Hasumi R, Kaya K, Watanabe H, Carter CC, Williamson JM, Miller TA. High-Resolution Laser-Induced Fluorescence Spectra of 7-Azaindole−Water Complexes and 7-Azaindole Dimer. J Phys Chem A 1997. [DOI: 10.1021/jp9614411] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Strauss I, Williamson JM, Bertram EH, Lothman EW, Fernandez EJ. Histological and 1H magnetic resonance spectroscopic imaging analysis of quinolinic acid-induced damage to the rat striatum. Magn Reson Med 1997; 37:24-33. [PMID: 8978629 DOI: 10.1002/mrm.1910370106] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
NAA has been described as a neuron-specific compound. NAA levels as determined by magnetic resonance spectroscopic imaging (MRSI) have been used to determine degree of neuronal loss in several neurological diseases, but there has been limited work to document the accuracy and reliability of this technique. This study addresses this question quantitatively with histological analysis of cell viability and tissue shrinkage in quinolinic acid (QA)-induced damage of the rat striatum compared with 1H MRSI measurement of N-acetyl aspartate (NAA) as a noninvasive measure of neuronal loss. Both 1H MRSI and histology detect damage to the lesioned striatum; however, there are differences in the degree of damage as assessed by the two methods. Although partial-volume effects and tissue shrinkage may decrease the sensitivity of MR to such damage, the sparing of axons by QA may be another important factor in the differences in assessment. These results indicate that further studies of NAA metabolism and its distribution within neurons are warranted.
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Schwarzer C, Williamson JM, Lothman EW, Vezzani A, Sperk G. Somatostatin, neuropeptide Y, neurokinin B and cholecystokinin immunoreactivity in two chronic models of temporal lobe epilepsy. Neuroscience 1995; 69:831-45. [PMID: 8596652 DOI: 10.1016/0306-4522(95)00268-n] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Somatostatin-, neuropeptide Y-, neurokinin B- and cholecystokinin-containing neurons were investigated in the rat hippocampus in two chronic models of temporal lobe epilepsy, i.e. 30 days after rapid kindling or electrically induced status epilepticus (post-status epilepticus). After rapid kindling, somatostatin immunoreactivity was strongly increased in interneurons and in the outer and middle molecular layer of the dentate gyrus. In four of six post-status epilepticus rats (status epilepticus I rats), somatostatin immunoreactivity was slightly increased in the dorsal but decreased in the ventral dentate gyrus and molecular layer. Somatostatin immunoreactivity decreased in neurons of the dorsal hilus in the two other post-status epilepticus rats investigated, while a complete loss was found in the respective ventral extension (status epilepticus-II rats). These changes were associated with a different extent of neurodegeneration as assessed by Nissl staining. Similarly, neuropeptide Y immunoreactivity was enhanced in neurons of the hilus and in the middle and outer molecular layer of the dentate gyrus in the dorsal hippocampus of rapidly kindled and status epilepticus-I rats. Neuropeptide Y and neurokinin B immunoreactivity was enhanced in the mossy fibers of all post-status epilepticus rats, but not in the rapidly kindled rats. In status epilepticus-II rats, neuropeptide Y-and neurokinin B-positive fibers were also detected in the infrapyramidal region of the stratum oriens of CA3 and in the inner molecular layer of the dentate gyrus in the dorsal and ventral hippocampus respectively, labeling presumably sprouted mossy fibers. Increased staining of neuropeptide Y and neurokinin B was found in the alveus after rapid kindling. Cholecystokinin immunoreactivity was markedly increased in the cerebral cortex, Ammon's horn and the molecular layer of the dentate gyrus in the ventral hippocampus of rapidly kindled and post-status epilepticus rats. The lasting changes in the immunoreactive pattern of various peptides in the hippocampus may reflect functional modifications in the corresponding peptide-containing neurons. These changes may be involved in chronic epileptogenesis, which evolves in response to limbic seizures.
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Wengler G, Gorlin JB, Williamson JM, Rosen FS, Bing DH. Nonrandom inactivation of the X chromosome in early lineage hematopoietic cells in carriers of Wiskott-Aldrich syndrome. Blood 1995; 85:2471-7. [PMID: 7537115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The Wiskott-Aldrich syndrome (WAS) is an X-linked (Xp11.22) recessive immunodeficiency syndrome characterized by susceptibility to opportunistic and pyogenic infections, thrombocytopenia, and eczema. Previous studies of obligate carriers of WAS documented that nonrandom inactivation of the X chromosome carrying the defective gene is observed in all peripheral blood cells. The existence of both abnormal platelets and lymphocytes is consistent with a defect that affects early hematopoietic precursors. We isolated CD34+ hematopoietic progenitor cells collected from obligate carriers of WAS by apheresis and used polymerase chain reaction analysis of a polymorphic variable number of repeats (VNTR) within the X-linked androgen receptor to document nonrandom inactivation. These data show that nonrandom inactivation of the X-chromosome in WAS-obligate carriers occurs early during hematopoietic differentiation.
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Johnson BA, Stevens SP, Williamson JM. Determination of the three-dimensional structure of margatoxin by 1H, 13C, 15N triple-resonance nuclear magnetic resonance spectroscopy. Biochemistry 1994; 33:15061-70. [PMID: 7999764 DOI: 10.1021/bi00254a015] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The solution structure of the 39-residue peptide margatoxin, a scorpion toxin that selectively blocks the voltage-gated potassium-channel Kv1.3, has been determined by NMR spectroscopy. The toxin was isotopically labeled with 13C and 15N and studied using two-dimensional homonuclear and three- and four-dimensional heteronuclear NMR spectroscopy. The final structure was determined using 501 constraints, comprising 422 NOE constraints, 60 dihedral angle constraints, 9 disulfide constraints, and 10 hydrogen bond constraints. Structures were initially determined with the program PEGASUS and subsequently refined with X-PLOR. The average rms deviation from a calculated average structure for the backbone atoms of residues 3-38 is 0.40 A. A helix is present from residues 11 to 20 and includes two proline residues at positions 15 and 16. A loop at residues 21-24 leads into a two-strand antiparallel sheet from residues 25 to 38 with a turn at residues 30-33. Residues 3-6 run adjacent to the 33-38 strand but do not form a canonical beta-strand. The two additional residues of margatoxin, relative to the related toxins charybdotoxin and iberiotoxin, insert in a manner that extends the beta-sheet by one residue. Otherwise, the global structure is very similar to that of these two other toxins. The longer sheet may have implications for channel selectivity.
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Lothman EW, Williamson JM. Closely spaced recurrent hippocampal seizures elicit two types of heightened epileptogenesis: a rapidly developing, transient kindling and a slowly developing, enduring kindling. Brain Res 1994; 649:71-84. [PMID: 7953657 DOI: 10.1016/0006-8993(94)91050-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Kindling is widely accepted as a model of chronic epilepsy as well as a model of plasticity in the nervous system. Conventional kindling studies have used infrequent stimuli (separated by many hours) to establish a fully kindled state in which enhanced responses (kindled motor seizures and protracted afterdischarges) are consistently triggered by stimuli that initially did not elicit such responses. The enhanced responses occur even after a prolonged stimulus-free interval. Whereas the establishment of a kindled state with traditional stimulus protocols takes several weeks, our previous work showed that kindling could take place much more quickly when the interstimulus interval was set at 30 min (rapid kindling). In this report we tested whether rapid kindling protocols share with traditional kindling protocols the ability to establish a fully kindled state. Using different stimulus protocols involving recurrent hippocampal seizures, we characterized two types of kindling. 'Rapid kindling' developed over hours, but was transient, with a decay rate of a few days so that a fully kindled state did not persist. In contrast, 'slow kindling' developed over several weeks and was enduring, apparently permanent, being associated with a fully kindled state. These findings suggest that, while having certain similarities, the two types of kindling arise from dissimilar mechanisms. The existence of these two types of kindling has implications for epileptogenesis in humans. Moreover, the protocols developed in this work provide a useful means to control for the effects of seizures that are not related to mechanisms underlying a fully kindled state.
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Williamson JM, Armour A. Microcystic endometrioid carcinoma of the fallopian tube simulating an adnexal tumour of probable wolffian origin. Histopathology 1993; 23:578-80. [PMID: 8314244 DOI: 10.1111/j.1365-2559.1993.tb01249.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Andrew AC, Williamson JM. Frozen section simulation of trabecular adenoma and medullary cancer by papillary thyroid carcinoma. J Clin Pathol 1993; 46:776-7. [PMID: 8408710 PMCID: PMC501472 DOI: 10.1136/jcp.46.8.776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Two patients are reported in whom initial misdiagnoses of medullary cancer or trabecular hyaline adenoma for papillary carcinoma were made.
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Abstract
Kindling is a widely used model of epilepsy. While intriguing hypotheses have recently emerged about how kindling occurs, the mechanisms behind kindling remain to be elucidated. In order to test whether certain anatomical changes that have been detected in the brains of animals that have completed kindling are necessary for the expression of kindled seizures, means to achieve kindling over a time course too rapid for the anatomical changes to take place were sought. Stimulus trains of various durations (2 and 10 s) and frequencies (20, 50, and 100 Hz) were given every 30 min, 12 times a day for 4 consecutive days to rats through bipolar electrodes stereotactically positioned in the ventral hippocampus. Responses were monitored with conventional kindling behavioral seizure scores and afterdischarge durations. The frequencies studied were chosen to survey the range that has been previously used to determine the optimal frequency for eliciting maximal dentate activation. Maximal dentate activation is a paroxysmal process that has been postulated to play both a role in regulating epileptiform activity in the hippocampus and adjacent regions that are coupled in a functional hippocampal-parahippocampal loop and a role in kindling. All types of trains resulted in rapid kindling in which kindled motor seizures emerged after several stimuli and then were consistently elicited with each stimulus; there was also retention of the kindled state after periods of 18 h of withholding the stimuli. Thus, the overall response profile of the rapid kindling demonstrated in this study was phenomenologically similar to the profile of traditional kindling. Yet rapid kindling developed more quickly than did mossy fiber sprouting, determined in prior work, thereby excluding the latter as a necessary factor in rapid kindling. Stimulus frequency significantly influenced the rate of rapid kindling. Trains of 20 Hz, the optimal frequency for eliciting maximal dentate activation, yielded the fastest kindling. This finding supports the proposed role of maximal dentate activation and the hippocampal-parahippocampal loop in kindling. Longer (10 s) trains consistently triggered shorter afterdischarge durations. We postulate that this may reflect a tighter linkage between seizure-terminating processes with the 10 s trains than with 2 s trains.
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Armour A, Williamson JM. Ectopic cervical hamartomatous thymoma showing extensive myoid differentiation. J Laryngol Otol 1993; 107:155-8. [PMID: 8496655 DOI: 10.1017/s0022215100122509] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ectopic 'hamartomatous' thymoma is a rare benign neoplasm. These tumours are found in the neck and are thought to be part of a spectrum of ectopic cervical thymic neoplasia. The clinical and histological features are discussed and the literature is reviewed. An attempt is made to explain in embryological terms why such lesions appear to occur more commonly on the left side.
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Lothman EW, Williamson JM. Influence of electrical stimulus parameters on afterdischarge thresholds in the rat hippocampus. Epilepsy Res 1992; 13:205-13. [PMID: 1493783 DOI: 10.1016/0920-1211(92)90054-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The influence of electrical stimulus parameters on focal seizure production was studied. Stimulations and recordings were carried out with bipolar electrodes stereotactically positioned in the ventral hippocampus of kindled rats. After discharge thresholds were determined for stimulus trains with different combinations of train durations (0.5, 1, 2, 5, 10 s), intratrain frequencies (10, 20, 50, 60, 100 Hz), and pulse widths (0.5 and 1.0 ms). For a given combination of pulse width and intratrain frequency, thresholds decreased as train duration increased; the effect was profound with shorter durations but markedly attenuated with train durations > or = 5 s. For a particular train duration and pulse width, thresholds varied inversely with intratrain frequency; the degree of variation in the thresholds with frequency was greater the shorter the train. For the train durations studied, thresholds were lower with 1.0-ms pulses for intratrain frequencies > or = 20 Hz. However, for 10 Hz, the 0.5-ms pulses were more effective for 2-, 5- and 10-s trains. After discharge thresholds were found to also vary with the number of pulses in the stimulus trains. For stimuli with fewer pulses, thresholds were higher and showed marked variation with train duration, intratrain frequency, and pulse width. For stimuli with more pulses, thresholds fell to a lower limit and the influence of train duration was substantially lessened. This study provides a systematic examination of the influence of stimulus parameters on generation of focal seizures and should prove useful in designing and interpreting future experiments studying the neurobiology of seizures in the hippocampus and related structures and helpful in antiepileptic drug testing.
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Williamson JM, Anderson MS, Raetz CR. Acyl-acyl carrier protein specificity of UDP-GlcNAc acyltransferases from gram-negative bacteria: relationship to lipid A structure. J Bacteriol 1991; 173:3591-6. [PMID: 1904441 PMCID: PMC207978 DOI: 10.1128/jb.173.11.3591-3596.1991] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Lipid A, the component of lipopolysaccharide that provides the membrane anchor of the core and O-antigen sugars, is known to contain characteristic R-3-hydroxy fatty acids bound to the 2,2' (N-linked) and 3,3' (O-linked) positions of the glucosamine disaccharide in different gram-negative bacteria. The studies reported here show that it is the acyl-acyl carrier protein specificities of the enzymes UDP-GlcNAc-O-acyltransferase and UDP-3-O-[(R)-3-hydroxyacyl]-GlcN-N-acyltransferase that determine the nature of these fatty acids.
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Williamson JM, Borduin CM, Howe BA. The ecology of adolescent maltreatment: a multilevel examination of adolescent physical abuse, sexual abuse, and neglect. J Consult Clin Psychol 1991. [PMID: 2071730 DOI: 10.1037//0022-006x.59.3.449] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This study examined the individual characteristics, family relations, and stress/social support of 50 maltreated adolescents and their mothers. Dyads were divided into 4 demographically similar groups: neglect, physical abuse, sexual abuse, and nonmaltreatment control. Results show that adolescent neglect was primarily associated with extrafamilial difficulties and social isolation. Adolescent physical abuse was linked more with rigidity in family relations, poorer maternal understanding of child developmental skills, and adolescent externalizing behaviors. In contrast, adolescent sexual abuse was related to maternal emotional problems and adolescent internalizing behaviors. In general, each group of maltreated adolescents experienced lower levels of family cohesion, more attention problems, and more daily stress than did their nonmaltreated counterparts. Findings are consistent with an ecological model of adolescent maltreatment.
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Lothman EW, Williamson JM, VanLandingham KE. Intraperitoneal phenytoin suppresses kindled responses: effects on motor and electrographic seizures. Epilepsy Res 1991; 9:11-8. [PMID: 1884715 DOI: 10.1016/0920-1211(91)90042-e] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Controversy has arisen about the effectiveness of phenytoin against kindled seizures. It has been suggested that the reports of ineffectiveness could be accounted for by phenytoin being given by an intraperitoneal (i.p.) route in those experiments so that adequate serum concentrations were not achieved. Another possibility for the different results was dissimilar stimulus protocols employed in the various studies. The present study examined these issues. Doses of i.p. phenytoin were studied for their actions against kindled responses elicited with short (1 s) and long (10 s) stimulus trains through hippocampal electrodes. Serial application of the stimuli determined time-action relationships. Dose-dependent effects were demonstrated for all time points examined. There was a consistently greater suppression of kindled motor seizures than limbic behavioral seizures or electrographic seizures. Phenytoin either totally blocked or did not affect the duration of afterdischarges. Actions of phenytoin against responses by short duration stimuli were greater than against long duration stimuli. Additional pharmacokinetic studies compared i.p. versus intravenous (i.v.) phenytoin. After i.p. phenytoin, serum levels peaked later than after i.v. delivery, but were maintained in the 'therapeutic' range longer. The present experiments provide additional support for the idea that kindled seizures are a useful model for complex partial seizures in humans. In addition, they show that major actions of phenytoin are to decrease seizure spread and to elevate afterdischarge thresholds and that the i.p. route is appropriate for assaying the effect of phenytoin against kindled seizures in rats.
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Stringer JL, Williamson JM, Lothman EW. Maximal dentate activation is produced by amygdala stimulation in unanesthetized rats. Brain Res 1991; 542:336-42. [PMID: 2029642 DOI: 10.1016/0006-8993(91)91588-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In urethane-anesthetized rats, a process termed maximal dentate activation has been shown to be associated with the lengthening of afterdischarges that occurs with repeated hippocampal stimulation. Maximal dentate activation is a unique paroxysmal form of epileptiform discharges consisting of large amplitude population spikes in the dentate gyrus. The current experiments examined the relationship of maximal dentate activation to kindling of motor seizures in the awake animal. Both long duration (5 or 10 s) and short duration (1 s) stimulus trains in either the hippocampus or the amygdala were effective in eliciting maximal dentate activation. Repeated stimulation of the amygdala produced lengthening of afterdischarges and kindling of motor responses, but only after maximal dentate activation had appeared in response to the stimulus. Over the course of amygdala kindling, the duration of maximal dentate activation lengthened with increasing severity of behavioral seizures. This evidence supports the hypothesis that maximal dentate activation is a marker for the presence of seizures distributed throughout limbic circuits. In addition, the data suggest that maximal dentate activation may be an important process involved in the acquisition of kindled responses.
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Williamson JM, Borduin CM, Howe BA. The ecology of adolescent maltreatment: A multilevel examination of adolescent physical abuse, sexual abuse, and neglect. J Consult Clin Psychol 1991; 59:449-57. [PMID: 2071730 DOI: 10.1037/0022-006x.59.3.449] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the individual characteristics, family relations, and stress/social support of 50 maltreated adolescents and their mothers. Dyads were divided into 4 demographically similar groups: neglect, physical abuse, sexual abuse, and nonmaltreatment control. Results show that adolescent neglect was primarily associated with extrafamilial difficulties and social isolation. Adolescent physical abuse was linked more with rigidity in family relations, poorer maternal understanding of child developmental skills, and adolescent externalizing behaviors. In contrast, adolescent sexual abuse was related to maternal emotional problems and adolescent internalizing behaviors. In general, each group of maltreated adolescents experienced lower levels of family cohesion, more attention problems, and more daily stress than did their nonmaltreated counterparts. Findings are consistent with an ecological model of adolescent maltreatment.
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Schaeffer JM, Frazier EG, Bergstrom AR, Williamson JM, Liesch JM, Goetz MA. Cochlioquinone A, a nematocidal agent which competes for specific [3H]ivermectin binding sites. J Antibiot (Tokyo) 1990; 43:1179-82. [PMID: 2211380 DOI: 10.7164/antibiotics.43.1179] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cochlioquinone A, isolated from the fungus Helminthosporium sativum, was found to have nematocidal activity. Cochlioquinone A is a competitive inhibitor of specific [3H]ivermectin binding suggesting that cochlioquinone A and ivermectin interact with the same membrane receptor.
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Goldman ME, Salituro GS, Bowen JA, Williamson JM, Zink DL, Schleif WA, Emini EA. Inhibition of human immunodeficiency virus-1 reverse transcriptase activity by rubromycins: competitive interaction at the template.primer site. Mol Pharmacol 1990; 38:20-5. [PMID: 1695317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Rubromycins, a class of quinone antibacterials, were discovered to selectively inhibit human immunodeficiency virus-1 (HIV-1) RNA-directed DNA polymerase (reverse transcriptase) (RT) activity more potently than cellular DNA polymerase alpha. beta- and gamma-rubromycin each inhibited equipotently HIV-1 RT and avian myeloblastosis virus RT, in a concentration-dependent manner, and were significantly weaker as inhibitors of calf thymus DNA polymerase alpha. These agents inhibited HIV-1 RT reversibly, were competitive with respect to template.primer, and were noncompetitive with respect to TTP. Dixon analyses yielded HIV RT Ki values of 0.27 +/- 0.014 and 0.13 +/- 0.012 microM for beta- and gamma-rubromycin, respectively. Similarly, using DNA polymerase alpha, the Ki values were 25.1 +/- 4.3 and 3.9 +/- 0.6 microM for beta- and gamma-rubromycin, respectively. Because these agents were toxic to noninfected human T lymphoid cells using concentrations at or above 6 microM, HIV-1 infectivity studies were carried out at 0.8-6 microM. At these concentrations, which are below the range expected to provide protection, no significant antiviral activity was observed. Although beta- and gamma-rubromycins did not possess sufficient HIV RT inhibitory potency or selectivity versus mammalian DNA polymerase to demonstrate antiviral activities, these studies support the hypothesis that specific molecules containing quinone functional groups can selectively inhibit viral polymerase activities over cellular polymerase activities. In addition, these studies suggest that rubromycins may be lead structures for the development of more potent and selective agents.
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Wilkins BS, Williamson JM, O'Brien CJ. Morphological and immunohistological study of testicular lymphomas. Histopathology 1989; 15:147-56. [PMID: 2777217 DOI: 10.1111/j.1365-2559.1989.tb03062.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have studied normal testis, seminomas and malignant lymphomas of the testis using routine stains and a panel of antibodies directed against lymphoid and basement membrane antigens. The results show that normal testis contains, at most, a minor population of T-lymphocytes: seminomas contain mixed T- and B-cell populations with a predominance of B-lymphocytes; and most primary lymphomas are B-cell tumours of large centroblastic type. Solid testicular lymphomas presenting secondarily to acute lymphoblastic leukaemias showed intact seminiferous tubular basement membranes with predominantly interstitial lymphomatous infiltrates, whereas the tubules in primary cases were over-run by lymphoma cells and basement membranes were disrupted.
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Stringer JL, Williamson JM, Lothman EW. Induction of paroxysmal discharges in the dentate gyrus: frequency dependence and relationship to afterdischarge production. J Neurophysiol 1989; 62:126-35. [PMID: 2754466 DOI: 10.1152/jn.1989.62.1.126] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
1. Electrical-stimulus trains activated hippocampal circuits in urethan-anesthetized rats. Responses were monitored with recordings of extracellular potentials and with measurements of the extracellular potassium ([K+]o). Stimulating electrodes were placed in the CA3 region contralateral to the recording electrode (cCA3) and in the ipsilateral angular bundle (AB) while recording in the CA1 pyramidal-cell layer or the granule-cell layer of the dentate gyrus. Patterns of maximal activation were identified. 2. In the CA1 region, maximal activation was indicated by the presence of 10- to 15-mV population spikes, a smooth rise in [K+]o of 5-6 mM above base-line levels of 3 mM, and a negative shift of the sustained DC potential of 2-4 mV. The dentate gyrus was considered to be maximally activated when bursts of large-amplitude (20-40 mV) population spikes were present. These population spikes were associated with a secondary rise in [K+]o to 6-8 mM above base line and an abrupt negative shift of the DC potential of 5-8 mV. 3. Maximal activation depended on the stimulus intensity, frequency, and duration. Trains of 10-Hz stimuli were used to determine the lowest stimulus intensity needed to elicit complete activation in CA1 and in the dentate gyrus. At this intensity, afterdischarges were not produced, and these responses could be elicited repeatedly. 4. By the use of this threshold stimulus intensity, cCA3 stimulation produced a rapid and progressive augmentation of CA1 responses until maximal activation was reached. In comparison, stimulation of the AB could produce the same end result, but the appearance of CA1 population spikes was delayed. Stimulation of the AB produced a steady increase in the evoked granule-cell population spike until the appearance of the paroxysmal large-amplitude population spikes. In contrast, cCA3 stimulation produced two positive evoked responses in the dentate gyrus before the paroxysms of population spikes began. 5. The frequency dependence of the responses was determined by giving stimulus trains ranging from 2 to 100 Hz. Stimulation of cCA3 produced population spikes in CA1 up to 100 Hz that were all associated with the same peak rise in [K+]o. AB stimulation only produced CA1 responses with stimulation frequencies between 15 and 25 Hz. The paroxysmal dentate population spikes were generated by stimulus frequencies between 15 and 30 Hz with both AB and cCA3 stimulation. 6. Unilateral colchicine injections caused a loss of dentate granule cells and a loss of maximal dentate activation on the side of the injection.(ABSTRACT TRUNCATED AT 400 WORDS)
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Williamson JM, Lothman EW. The effect of MK-801 on kindled seizures: implications for use and limitations as an antiepileptic drug. Ann Neurol 1989; 26:85-90. [PMID: 2549848 DOI: 10.1002/ana.410260113] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
MK-801 is a new drug that produces a noncompetitive blockade at the subclass of glutamate receptors activated by N-methyl-D-asparate (NMDA). The antiepileptic properties of MK-801 were studied using kindled seizures as a model of complex partial seizures with secondary generalization. A test protocol was employed that allowed: (1) examination of the efficacy of MK-801 against several parameters that gauge different aspects of epileptogenesis; (2) determination of the time-action profile of these effects; and (3) examination of the toxicity of MK-801 in animals experiencing seizures. The drug was found to be potent against the spread of seizures but less effective against parameters linked to partial seizures. At the higher doses of the drug required to truncate hippocampal afterdischarges, considerable neurotoxicity was encountered. In addition, the antiepileptic effects of MK-801 showed a use dependence so that, at a given time after the drug was administered, a greater suppression of seizures was noted if there had been preceding seizures in the presence of the drug than if there had not been. These findings indicate that there may be limitations to the clinical utility of MK-801 as an antiepileptic agent and that the drug may provide greatest benefit when used for the suppression of seizure generalization and when seizures are closely spaced.
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Pettibone DJ, Clineschmidt BV, Anderson PS, Freidinger RM, Lundell GF, Koupal LR, Schwartz CD, Williamson JM, Goetz MA, Hensens OD. A structurally unique, potent, and selective oxytocin antagonist derived from Streptomyces silvensis. Endocrinology 1989; 125:217-22. [PMID: 2544402 DOI: 10.1210/endo-125-1-217] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The in vitro and in vivo oxytocin/arginine vasopressin (OT/AVP) antagonist properties of two cyclic hexapeptides derived from a newly discovered natural product (L-156,373) of Streptomyces silvensis are described. In radioligand binding assays, L-156,373 [cyclo(L-Pro-D-Phe-N-OH-L-Ile-D-piperazyl-L-piperazyl-N-Me-D -Phe)] exhibited moderate affinity for rat uterine OT receptors (Ki, 150 nM), with some selectivity (approximately 20-fold) vs. liver AVP-V1 and kidney AVP-V2 receptors. Dehydroxylation of N-hydroxyisoleucine and oxidation of the piperazic acid residues of L-156-373 produced an interesting derivative, L-365,209. These structural modifications increased OT receptor affinity and selectivity by 20- and 2.5-5-fold, respectively. In the isolated rat uterus, L-365,209 was a potent (apparent dissociation constant, 1.7 nM) and competitive OT antagonist. L-365,209 also blocked the effects of AVP at both AVP-V1 (phosphatidylinositol turnover in rat hepatocytes) and AVP-V2 (adenylate cyclase in rat kidney medulla) receptors, but only at low micromolar concentrations. L-365,209, given iv to anesthetized rats, antagonized the action of exogenous OT on the uterus (ID50, 460 micrograms/kg) with a relatively long duration of action. L-365,209 represents a unique class of compounds that provides an entirely new approach for the design of antagonists for these neurohypophyseal hormones.
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Williamson JM, Grigor I, Smith ME, Holgate CS, O'Brien CJ, Morgan DR, Quirke P, Alison DL, Child JA, Bird CC. Ploidy, proliferative activity, cluster differentiation antigen expression and clinical remission in high-grade non-Hodgkin's lymphoma. Histopathology 1987; 11:1043-54. [PMID: 3509751 DOI: 10.1111/j.1365-2559.1987.tb01844.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Using a large range of monoclonal antibodies to specific cluster differentiation antigens the phenotypes of a series of high-grade non-Hodgkin's lymphomas of B- and T-cell type were investigated. Cell ploidy and proliferative fraction were assessed by fluorescent staining of DNA and flow cytometry and data on the incidence of complete clinical remission were obtained. With the exception of some lymphoblastic lymphomas, high-grade B-cell lymphomas normally expressed the pan B-cell antigens CD19 and CD22 but only immunoblastic lymphomas consistently expressed the pan B marker CD20. Variable, generally weak expression of CD21 was observed whilst CD23 expression was most prevalent in rapidly proliferative cases and in Burkitt's and centroblastic lymphomas. A rapidly proliferative, multilobated B-cell lymphoma displayed phenotypic properties intermediate between centroblastic and immunoblastic lymphomas. The T-cell lymphomas generally showed low proliferative activity and expression of CD4 prevailed over CD8. Most cases also showed CD2 and CD5 positivity with some also showing CD3 and CD7 expression. Patients with rapidly proliferative diploid or DNA aneuploid tumours obtained complete remission more readily than patients with lowly proliferative diploid tumours. An excess of early deaths occurred among T-cell cases.
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50
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Burke DA, Manning AP, Williamson JM, Axon AT. Adverse reactions to sulphasalazine and 5-amino salicylic acid in the same patient. Aliment Pharmacol Ther 1987; 1:201-8. [PMID: 2908750 DOI: 10.1111/j.1365-2036.1987.tb00619.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report a patient who developed sulphasalazine-related hepatitis with a subsequent adverse reaction to rectal 5-amino salicylic acid, in the form of pain and fever without associated liver dysfunction, suggesting reactions to both components of sulphasalazine. Included is a review of the literature. Caution should be observed when prescribing 5-amino salicylic acid to sulphasalazine-intolerant patients.
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