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Biomedical subjects

J L Thompson

Publications and source records attributed to J L Thompson.

At least 19 recordsLinked to original sources
PubMed1995

Hypertension and diabetes mellitus as determinants of multiple lacunar infarcts.

BACKGROUND AND PURPOSE: We investigated the relationship between hypertension, diabetes mellitus, and lacunes. METHODS: From 1237 cases of ischemic stroke in the Stroke Data Bank of the National Institute of Neurological and Communicative Disorders and Stroke, data from 637 patients whose initial computed tomogram showed lacunar (n = 184) or nonlacunar infarcts (n = 453) were analyzed. The group with lacunar infarcts was further divided into subgroups according to whether the patients had multiple (n = 40) or single (n = 144) lacunar infarcts. The association of hypertension and diabetes mellitus with lacunar infarcts was investigated using logistic regression models that included age, sex, and cardiac disease. Similar models were used to analyze the effects of diastolic and systolic blood pressure. RESULTS: Hypertension (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1 to 6.0) and diabetes (OR, 2.3; 95% CI, 1.1 to 4.5) were significantly related to multiple but not to single lacunes. Cardiac disease was inversely associated with both single and multiple lacunes. Diastolic blood pressure significantly affected the probability of multiple lacunar infarcts (OR, 1.4; 95% CI, 1.04 to 1.9), whereas systolic pressure did not. CONCLUSIONS: There may be etiologically distinct lacunar infarct subgroups, with multiple lacunes being strongly related to hypertension and diabetes mellitus. Other stroke risk factors may be more important in patients with single lacunes. Diastolic rather than systolic pressure seems to be a major determinant of multiple lacunes.

Adult↗
PubMed1995

Transcranial Doppler ultrasonography in cerebral arteriovenous malformations. Diagnostic sensitivity and association of flow velocity with spontaneous hemorrhage and focal neurological deficit.

BACKGROUND AND PURPOSE: We sought to investigate (1) the sensitivity of transcranial Doppler ultrasonography (TCD) for diagnosis of cerebral arteriovenous malformations (AVMs) and (2) the association of feeding artery flow velocity profiles with spontaneous hemorrhage and focal neurological deficit in AVM patients. METHODS: We examined 114 consecutive AVM patients prospectively by TCD; 22 non-AVM patients with acute cerebral hemorrhage and 52 normal subjects served as controls. To estimate the association of blood flow velocity patterns in feeding arteries with spontaneous hemorrhage and focal neurological deficit, the total group of AVM subjects was divided into patients with and without a history of bleeding and also into those with and without clinical signs of "steal" (focal deficit unrelated to hemorrhage). RESULTS: Sensitivity for large and medium-sized AVMs was high (> 80%), whereas 62% of small AVMs were missed. TCD was also highly sensitive (80%) in a group of five AVM patients with acute hemorrhage. Flow velocity profiles were not related to spontaneous hemorrhage (mean velocity, 111 cm/s in patients with hemorrhage versus 114 cm/s in patients without hemorrhage; P = .65) or clinical signs of steal (mean velocity, 111 cm/s versus 113 cm/s in patients with and without steal, respectively; P = .89). CONCLUSIONS: We concluded that (1) TCD is highly sensitive for large and medium-sized AVMs; (2) in acute cerebral hemorrhage TCD may help to differentiate AVM from non-AVM bleeds; (3) the predictive value of TCD findings for clinical sequelae of AVMs remains undetermined; and (4) the concept of hemodynamic steal in AVMs is not supported by TCD data.

Adult↗
PubMed1995

The effects of recombinant human insulin-like growth factor-I and growth hormone on body composition in elderly women.

The purpose of this study was to determine the effects of recombinant human GH (rhGH; 0.025 mg/kg.day) and one of two doses of recombinant human insulin-like growth factor-I (rhIGF-I; 0.015 and 0.060 mg/kg, twice daily) on body composition in elderly women. Sixteen healthy elderly women (mean age +/- SEM, 71.9 +/- 1.3 yr) were randomly assigned to receive either rhGH (GH; n = 5), low dose rhIGF-I (n = 6), or high dose rhIGF-I (n = 5). A 2-week predrug baseline period was followed by 4 weeks of hormone treatment, with a standardized diet fed throughout. All groups experienced a significant increase in serum IGF-I and IGFBP-3 levels over the treatment period, accompanied by significant decreases in IGF-II (P < 0.05). Fat mass decreased in all groups, with significant increases in lean body mass and nitrogen retention occurring in the high dose IGF and GH groups. Total body water did not change, whereas increases observed in intracellular fluid approached significance (P = 0.06). These anabolic changes were accompanied by numerous negative side-effects in the GH and high dose IGF groups, including headaches, lethargy, joint swelling/pain, and bloatedness. The low IGF dose was well tolerated. These results demonstrate that the administration of rhGH and rhIGF-I for 4 weeks results in anabolic changes in body composition in elderly women.

Aged↗
PubMed1995

Daily energy expenditure in male endurance athletes with differing energy intakes.

The 24-h energy expenditure (24-h EE), resting EE (REE), sleeping EE (SEE), and spontaneous physical activity (SPA) were compared between six male endurance athletes whose reported energy intake was low (LOW) and did not match that theoretically required for weight maintenance and four whose reported energy intake appeared adequate (ADQ) and matched their estimated EE. Groups did not differ in age, body weight, fat-free mass, and daily EE estimated from activity records. The LOW athletes reported an energy intake 6338 +/- 2164 kJ.d-1 less than estimated EE. The 24-h EE, REE, SEE, and SPA of the LOW athletes were significantly lower than the ADQ athletes (862, 523, 770 kJ.d-1, and 43 min.d-1, respectively). Using all subjects, there was a significant positive correlation between REE and free thyroxine (FT4) (r = 0.82) and SEE and FT4 (r = 0.66). Thus, part of the LOW athlete's ability to maintain body weight on a seemingly low energy intake appears due to a lower daily sedentary EE.

Activities of Daily Living↗
PubMed1994

Cardiac sources of embolism in patients with pial artery infarcts and lacunar lesions.

BACKGROUND AND PURPOSE: On the assumption that the majority of lacunes are caused by small-vessel diseases and that pial artery infarcts arise from cardio-embolic or large-vessel diseases, 194 patients from the Berlin Cerebral Ischemia Data Bank with either lacunar or pial artery infarcts were analyzed for the frequency of cardiac sources of embolism. The primary hypothesis was that the frequency of cardiac sources of embolism is higher among pial artery infarct subjects. METHODS: The presence of cardiac sources of embolism was estimated by electrocardiographic and transthoracic and transesophageal echocardiographic studies. Cranial computed tomography scans were evaluated by two masked observers. RESULTS: The overall rate of cardiac sources of embolism did not differ significantly between the lacunar and the pial artery infarct group (66% versus 71%; odds ratio, 0.80; confidence interval, 0.43 to 1.50). Echocardiographic evidence of cardiac thrombi was positively associated with pial artery infarcts (odds ratio, 0.18; confidence interval, 0.04 to 0.80); atrial fibrillation and all other cardiac sources were not. CONCLUSIONS: Left cardiac thrombi are significantly associated with pial artery infarcts. Other presumed cardiac sources of embolism, including atrial fibrillation, may often represent coincidental findings or have a less strong tendency to result in pial artery infarcts.

Adolescent↗
PubMed1993

Estimated condom failure and frequency of condom use among gay men.

OBJECTIVES: Condoms are designed to bar transmission of the human immunodeficiency virus (HIV), but they sometimes fail. This paper explores the effect of experience with condoms on condom failure among gay men. METHODS: Risk of condom failure (breakage or slippage) on a single occasion is estimated for four sexual acts reported over 12 months by a sample of gay New York City men (n = 741). The estimation procedure assumes that each episode in which a condom is used is an independent event. Evidence is offered to support this assumption. RESULTS: Risk of condom failure in a single episode was fairly high, particularly in anal intercourse, for men who had engaged in each act only a few times in the previous year. It declined rapidly with experience (e.g., to below 1% for receptive anal intercourse after about 10 episodes in the previous year). Condoms failed less often in oral than anal sex, but estimated risk of failure also decreased with experience. CONCLUSIONS: Gay men should be especially cautious the first few times they use a condom; after moderate experience, however, they may expect a low risk of condom failure.

Adolescent↗
PubMed1992

Kainic acid seizures in the developing brain: status epilepticus and spontaneous recurrent seizures.

Acute and chronic effects of seizures induced by intraperitoneal (i.p.) injection of kainic acid (KA) were studied in developing rats (postnatal days (P) 5, 10, 20, 30, and adult 60). For 3 months following KA-induced status epilepticus, spontaneous recurrent seizure (SRS) occurrence was quantified using intermittent video monitoring. Latency to generalized seizures was then tested using flurothyl, and brains were histologically analyzed for CA3 lesions. In P5-10 rats, KA caused generalized tonic-clonic ('swimming') seizures. SRS did not develop, and there was no significant difference between control and KA-treated rats in latency to flurothyl-induced seizures. In contrast, rats P20 and older exhibited limbic automatisms followed by limbic motor seizures which secondarily generalized. Incidence and frequency of SRS increased with age. P20-30 rats with SRS had shorter latencies to flurothyl seizures than did KA-treated P20-30 rats without SRS or controls. KA-treated P60 rats (with or without SRS) had shorter latencies than controls to flurothyl seizure onset. SRS in P60 rats occurred sooner after KA than in P20-30 rats. CA3 lesions were seen in P20-60 rats with and without SRS, but not in P5-10 rats. These data suggest that there are developmental differences in both acute and chronic responses to KA, with immature animals relatively protected from the long-term deleterious effects of this convulsant.

Aging↗
PubMed1992

Effects of neural transplantation on seizures in the immature genetically epilepsy-prone rat.

To study the hypothesis that neural transplantations can alter seizure susceptibility in a genetic animal model of epilepsy, 93 pubescent genetically epilepsy-prone rats with stage 9 seizures received either bilateral inferior colliculi (N = 21) or lateral ventricle (N = 42) transplants or sham transplants (N = 30). The grafts consisted of embryonic locus ceruleus, neocortical, or cerebellar tissue. Starting 2 days after the transplantation the rats were subjected to audiogenic stimulations every other day for 61 days. Latency to the running and tonic phase, seizure severity score, and duration of the tonic and clonic phase were compared in the neural transplant and sham-operated controls. Rats that received transplants had a longer latency to the tonic phase and a shorter duration of the clonic phase than the controls. At age 110 days the rats had electrodes implanted bilaterally into the angular bundle and were kindled. No difference in kindling rate was found between the rats that received neural grafts and the sham-operated controls. Cerebrospinal fluid concentration of norepinephrine was not altered by the transplants. This study demonstrates that the anticonvulsant effects of neural transplants, using the genetically epilepsy-prone model of epilepsy, are mild.

Acoustic Stimulation↗
PubMed1992

Modulation of inositol(1,4,5)trisphosphate-sensitive calcium store content during continuous receptor activation and its effects on calcium entry.

Changes in intracellular Ca2+ concentration ([Ca2+]i) following the activation of muscarinic receptors with carbachol were studied in cells from the exocrine avian nasal gland that had been maintained in culture for 40-48 h. In these cells, the carbachol-induced sustained increase in [Ca2+]i could be further increased by the subsequent addition of thapsigargin. This increase was due to an additional release of intracellular Ca2+ and a corresponding further enhancement of Ca2+ entry. However, thapsigargin-sensitive and Ins(1,4,5)P3-sensitive stores appeared to be coincident and the initial carbachol stimulus was sufficient to completely empty these stores. It was concluded that the subsequent effect of thapsigargin was due to a partial refilling of the Ins(1,4,5)P3-sensitive stores despite the continued presence of agonist, an effect that was not the result of any decline in levels of cellular Ins(1,4,5)P3 or changes in the generation of Ins(1,3,4,5)P4, which were sustained throughout. Possible explanations for this refilling response include compartmentalization of intracellular Ins(1,4,5)P3, or a desensitization of the Ins(1,4,5)P3 receptor/Ca(2+)-release channel. Alternatively, the data are also compatible with a recently proposed kinetic separation of Ca2+ uptake and release sites. An important implication of this particular interpretation of our findings would be an apparent dependence of Ca2+ entry specifically on the status of the Ca(2+)-uptake component of the agonist-sensitive store, rather than the Ca(2+)-release component.

Animals↗
PubMed1992

AMP deaminase histochemical activity and immunofluorescent isozyme localization in rat skeletal muscle.

The cellular distribution of AMP deaminase (AMPda) isozymes was documented for rat soleus and plantaris muscles, utilizing immunofluorescence microscopy and immunoprecipitation methods. AMPda is a ubiquitous enzyme existing as three distinct isozymes, A, B and C, which were initially purified from skeletal muscle, liver (and kidney), and heart, respectively. AMPda-A is primarily concentrated subsarcolemmally and intermyofibrillarly within muscle cells, while isozymes B and C are concentrated within non-myofiber elements of muscle tissue. AMPda-B is principally associated with connective tissues surrounding neural elements and the muscle spindle capsule, and AMPda-C is predominantly associated with circulatory elements, such as arterial and venous walls, capillary endothelium, and red blood cells. These specific localizations, combined with documented differences in kinetic properties, suggest multiple functional roles for the AMPda isozymes or temporal segregation of similar AMPda functions. Linkage of the AMPda substrate with adenosine production pathways at the AMP level and the localization of isozyme-C in vascular tissue suggest a regulatory role in the microcirculation.

AMP Deaminase↗
PubMed1991

Effect of neural transplants on seizure frequency and kindling in immature rats following kainic acid.

To study the hypothesis that neural transplantations can alter seizure susceptibility in a chronic animal model of epilepsy 260 immature rats (30- to 32-days-old) were administered a convulsant dosage of kainic acid (KA). Ten days later rats that had severe seizures following KA received either bilateral intracerebroventricular transplants of hippocampal (n = 27), neocortical (n = 29), cerebellar (n = 30), or locus ceruleus (n = 32) tissue, or underwent sham transplantation (n = 66). Spontaneous seizure frequency was assessed for 230 days following which the rats underwent entorhinal kindling. The percentage of rats developing spontaneous recurrent seizures was similar in the 4 transplant groups and the sham-operated controls. Rats receiving hippocampal and locus ceruleus transplants had fewer spontaneous seizures than the sham-operated controls or other transplant groups. However, there were no differences in afterdischarge thresholds or kindling rates in the 5 groups. This study demonstrates that the anticonvulsant effects of neural transplants, using this animal model are mild. Tissue type of the graft appears to be an important variable in the alteration of seizure frequency.

Animals↗
PubMed1991

Effect of temperature on receptor-activated changes in [Ca2+]i and their determination using fluorescent probes.

Several recent studies of intracellular Ca2+ concentration ([Ca2+]i using fluorescent indicators have involved experiments performed at nonphysiological temperatures, frequently room temperature. In the studies reported here, a reduction in temperature was shown to influence the measurement of [Ca2+]i in two major ways. The first is an effect on the value for the Kd (apparent dissociation constant) used in the calculation of [Ca2+]i. The Kd values for indo-1 and fura-2 were found to change with temperature in a manner analogous to the related compounds [ethylene-bis(oxyethylenenitrilo)]tetraacetic acid and bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid. Experiments showed that the use of previously published Kd values (measured at 37 degrees C) in experiments at room temperature results in errors of at least 25% in the calculated [Ca2+]i. The second arises from the differential temperature sensitivities of the physiological processes that make up any particular value of [Ca2+]i. While resting [Ca2+]i was relatively unaffected by reduced temperature (27 degrees C, 13 degrees C), changes in [Ca2+]i following stimulation were profoundly influenced and in a way that was not simply predictable. Analysis of the responses indicated that the observed effects resulted largely from a temperature-dependent reduction in the rate of Ca2+ removal from the cytosol together with an additional component, namely a marked reduction in Ca2+ entry, at the lower temperature (13 degrees C). The net result was observed as changes in the initial rise in [Ca2+]i on stimulation, together with more profound, and complex, effects on the sustained elevation in [Ca2+]i following stimulation. This latter component was markedly increased at 27 degrees C, but was decreased in cells at 13 degrees C.

Animals↗
PubMed1991

Exploring gender and culture with Khmer refugee women: reflections on participatory feminist research.

This article discusses the process and findings from a study based on the paradigm of feminist participatory research. The research is first discussed in relation to contemporary feminist scholarship. The project combined elements of community health nursing practice and feminist research in a support group with Khmer refugee women. The research explored psychosocial adjustment and the construction of gender among Khmer women. Methods of data collection included life history and trauma history interviews, discussion of dream narratives and Cambodian myths, and participant observation. Findings included four recurring themes identified in the women's stories. The research process is discussed in terms of its implications for nursing praxis.

Cambodia↗
PubMed1991

Behavioral state-specific changes in human hippocampal theta activity.

Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.

Adolescent↗
PubMed1990

The effect of regional differences in noradrenergic neuron growth patterns on juvenile kindling.

Kindling can be altered by a variety of lesions designed to deplete norepinephrine (NE). However, the effect of the regional alteration in NE concentration on seizure susceptibility has not been studied. Two different concentrations of 6-hydroxydopamine (6-OHDA) were administered to one-day-old rat pups. At age 18 days, rat with significant rostral brain NE loss, due to high dose 6-OHDA, had a faster rate of electrical kindling in the entorhinal cortex than controls. In contrast rats receiving low dose 6-OHDA which resulted in comparable forebrain NE depletion but with a dramatic hindbrain noradrenergic overgrowth showed no enhancement of kindling. These results suggest that in the immature rat the proconvulsant effect of forebrain NE depletion can be overridden by an augmentation of hindbrain NE growth patterns.

Adrenergic Fibers↗
PubMed1990

Effects of seizures on learning, memory, and behavior in the genetically epilepsy-prone rat.

To determine whether frequent seizures can cause deficits in learning and behavior, immature genetically epilepsy-prone rats (GEPRs) were subjected to 66 audiogenic stimulations (Group 1). GEPR littermates were handled and placed in the sound chamber but were not stimulated (Group 2). Group 3 comprised genetically epilepsy-resistant rats (GERRs) who received audiogenic stimulations but had no seizures. After 3 weeks of stimulations the rats were tested for learning, memory, and behavior using the T-maze, water maze, open field activity test, home cage intruder test, and handling test. When compared with the control GEPRs and GERRs, Group 1 rats reached criteria less frequently in the T-maze, required longer times to find the platform in the water maze, and were less active in the open field activity test, less aggressive in the home cage intruder test, and more irritable and aggressive in the handling test. This study demonstrates that frequent, brief seizures in immature animals result in significant detrimental changes in learning, memory, activity level, and behavior.

Acoustic Stimulation↗
PubMed1990

Effect of 2-amino-7-phosphonoheptanoic acid (APH) on seizure susceptibility in the prepubescent and mature rat.

There is now considerable evidence that the N-methyl-D-aspartic acid receptor is important in the genesis of seizures. One of the selective antagonist of the NMDA receptor is 2-amino-7-phosphonoheptanoic acid (APH). In this study we evaluated the effects of intracerebroventricular (i.c.v.) administration of APH on seizure susceptibility in both prepubescent and mature rats using the rapid kindling and flurothyl ether seizure models. Both the immature and mature animals receiving APH kindled at a significantly slower rate than control animals receiving phosphate-buffered saline. APH also demonstrated a significant anticonvulsant effect against flurothyl-induced seizures in both the immature and mature animals. This study supports prior work that selective NMDA receptor antagonists such as APH may have promise as potential antiepileptic agents.

2-Amino-5-phosphonovalerate↗