PubMed Health⌕ Search

Biomedical subjects

J C Torner

Publications and source records attributed to J C Torner.

At least 55 records · Page 3Linked to original sources
PubMed1993

A randomized trial of nicardipine in subarachnoid hemorrhage: angiographic and transcranial Doppler ultrasound results. A report of the Cooperative Aneurysm Study.

Calcium antagonist drugs were proposed for use in patients with recent aneurysmal subarachnoid hemorrhage (SAH) because of their ability to block the effects of a wide variety of vasoconstrictor substances on cerebral arteries in vitro. It was suggested that these agents might, therefore, be useful in ameliorating cerebral vasospasm and its ischemic consequences which frequently complicate SAH. This hypothesis was tested in an arm of a randomized double-blind placebo-controlled trial of high-dose intravenous nicardipine in patients with recently ruptured aneurysms. Participating investigators were required to send selected copies of all admission and follow-up angiograms obtained between Days 7 and 11 following hemorrhage (the peak period of risk for vasospasm) to the Central Registry of the Cooperative Aneurysm Study for blinded interpretation and review for the presence and severity of angiographic vasospasm. In centers with transcranial Doppler ultrasound (TCD) capabilities, middle cerebral artery (MCA) mean flow velocities were measured and recorded. Angiograms obtained between Days 7 and 11 were available for 103 (23%) of 449 patients receiving nicardipine and 121 (26%) of 457 receiving placebo. There was a balance of prognostic factors for vasospasm between the groups. Fifty-one percent of placebo-treated patients had moderate or severe vasospasm on "Day 7-11 angiograms" compared to 33% of nicardipine-treated patients. This difference is statistically significant (p < 0.01). Sixty-seven (49%) of 137 placebo-treated patients examined with TCD between Days 7 and 11 had mean MCA flow velocities exceeding 120 cm/sec compared to 26 (23%) of 112 nicardipine-treated patients (significant difference, p < 0.001). These data suggest that high-dose intravenous nicardipine reduces the incidence and severity of delayed cerebral arterial narrowing in patients following aneurysmal SAH.

Adult↗
PubMed1992

Cerebrovascular effects of substance P after experimental subarachnoid haemorrhage.

The vasoactive effects of substance P (SP), as well as the content of cyclic guanine monophosphate (cGMP), were determined in the rabbit basilar artery after subarachnoid haemorrhage (SAH). Out of 47 rabbits, 24 were subjected to a SAH, induced by injecting 5 ml of autologous arterial blood into the cisterna magna; 23 were used as controls. In 20 animals (10 SAH and 10 controls), isometric tension recording of isolated rings of the basilar artery--dissected 2 days after SAH--was employed to assess the dose-dependent vasodilatation to SP (10(-10) to 10(-6) M) after precontraction with serotonin (10(-8) to 10(-5) M). In 15 animals (8 SAH and 7 controls), the basal cGMP content was measured in the basilar artery 2 days after SAH. In the other 12 animals (6 SAH and 6 controls), the increase in cGMP content was measured in the basilar artery after a 10-minute incubation with SP (10(-6) M). SP caused significantly less dilatation in animals subjected to SAH than in controls, especially for concentrations between 10(-9) and 10(-6) M (p < 0.001). The cGMP content in the arteries 2 days after SAH was significantly lower than in control arteries (31.5 +/- 7.3 against 57.3 +/- 4.3 pmoles/g tissue). In the preparations incubated with SP, the increase of cGMP was 440 +/- 115% in the control arteries, and only 97 +/- 30% in the arteries after SAH. It is concluded that the vasodilator activity of SP is significantly impaired after SAH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Impact of unruptured intracranial aneurysms on public health in the United States.

BACKGROUND AND PURPOSE: Unruptured intracranial aneurysms constitute a significant public health problem that has not been quantified. The purpose of this study is to document the magnitude of this problem in the United States. METHODS: National Hospital Discharge Survey data from 1979, 1984, and 1989 served as the basis for calculating patient numbers and frequency distributions. Cost estimates included the direct costs of hospitalization and surgery for those who had surgery, disability and lost income from morbidity, and lost income from mortality. RESULTS: The estimated lifetime cost (including hospitalization, surgery, morbidity, and mortality) for annual cases of patients hospitalized with unruptured intracranial aneurysms in the United States is $522,500,000 compared with $1,755,600,000 for patients with aneurysmal subarachnoid hemorrhage. CONCLUSIONS: These data underscore the need to better understand unruptured intracranial aneurysm as a risk factor for subarachnoid hemorrhage, to define other subarachnoid hemorrhage risk factors, and to optimize the management of patients with these conditions.

Aged↗
PubMed1992

The International Cooperative Study on the Timing of Aneurysm Surgery. The North American experience.

BACKGROUND AND PURPOSE: The timing of aneurysm surgery after subarachnoid hemorrhage is a major neurosurgical controversy addressed by the International Cooperative Study on the Timing of Aneurysm Surgery (1980-1983). The present report examines the results of this trial in the subgroup of patients admitted to North American centers. METHODS: The method of study was a large, multicenter, prospective, epidemiological survey. Neurosurgeons were required to indicate prospectively the interval to planned aneurysm surgery at the time of patient admission. Outcome at 6 months was determined by a blinded evaluator, and overall management results were analyzed by the planned surgical interval. RESULTS: Seven hundred seventy-two (21.9% of the total study population) patients admitted from days 0 to 3 after subarachnoid hemorrhage were accrued in North American centers. Overall outcome in patients planned for surgery in days 0-3 was equivalent in terms of mortality (after adjustment for prognostic variables) to patients planned for days 11-32, but the early patients had significantly improved rates of good recovery (70.9% versus 61.7%, p less than 0.01). Patients planned for surgery during the days 7-10 interval had nearly twice the mortality of patients in the other intervals. CONCLUSIONS: In contrast to the results from the overall trial, which found no difference between early and delayed surgery, results were best in North American centers when surgery was planned between days 0 and 3 after subarachnoid hemorrhage. These findings argue strongly for early diagnosis and referral for surgical intervention of North American patients suspected of having a ruptured cerebral aneurysm.

Adult↗
PubMed1992

Urgent therapy for stroke. Part II. Pilot study of tissue plasminogen activator administered 91-180 minutes from onset.

BACKGROUND AND PURPOSE: Renewed interest in thrombolytic therapy as potential treatment for patients with acute ischemic stroke prompted a dose-escalation safety study of tissue plasminogen activator in patients with very early (less than or equal to 90 minutes; see Part I) neurological symptoms. To test whether this stringent entry window might be safely lengthened, a second study was organized to test tissue plasminogen activator in patients with symptoms of 91-180 minutes' duration before treatment. METHODS: An open-label, dose-escalation design was chosen. Eligible patients had pretreatment head computerized tomographic scanning and treatment begun 91-180 minutes from stroke onset. End points examined included the incidence of symptomatic and asymptomatic intracranial hemorrhage, other bleeding, and clinical outcome at 2 hours, 24 hours, and 3 months after treatment. RESULTS: Twenty patients were treated at three hospitals in 13 months. Three doses were tested: 0.6 mg/kg (n = 8), 0.85 mg/kg (n = 6), and 0.95 mg/kg (n = 6). Two patients, one each at the two highest doses, sustained fatal intracerebral hemorrhages. Three patients (15%) improved by greater than or equal to 4 points on the National Institutes of Health Stroke Scale by 24 hours. CONCLUSIONS: These observations suggest that tissue plasminogen activator treatment of acute ischemic stroke 91-180 minutes from onset in doses of greater than or equal to 0.85 mg/kg is attended by a risk of intracerebral hemorrhage approximating 17% (range 3-44%, 95% confidence interval). The rate of early neurological improvement observed in this study was small but does not exclude an improvement over the natural history. Future study with placebo control subjects and stratification by time to treatment is indicated.

Aged↗
PubMed1992

The epidemiology of myasthenia gravis in central and western Virginia.

We conducted a study of the epidemiology of myasthenia gravis (MG) in four locations in central and western Virginia from 1970 through 1984. The population surveyed was 555,851 in 1984. A total of 73 new cases of MG occurred during the survey period, producing an overall average annual incidence rate of 9.1 per million. The point prevalence rate in 1980 was 13.4 per 100,000, and in 1984 it was 14.2. Approximately 15% of the population was black, and we found that incidence and prevalence rates for the black population were higher than the corresponding white population. When the population was subdivided into <50 and 50+ age groups, the incidence and prevalence were significantly higher in the older group. The rates we report here are higher than rates reported from any other locality. The reasons for the higher rates include optimal case identification, survey of a population with a higher incidence, and increasing aging of the population.

Adult↗
PubMed1992

Effect of nicardipine on basilar artery vasoactive responses after subarachnoid hemorrhage.

The effect of the dihydropyridine calcium antagonist, nicardipine, on the vasoactive responses of the basilar artery was investigated after subarachnoid hemorrhage (SAH). Forty-five rabbits were separated into one control group and four groups receiving SAH (nine animals each). The SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. SAH animals were subjected to one of the following: 1) no treatment; 2) intravenous (i.v.) saline infusion (vehicle); 3) i.v. infusion of low-dose nicardipine (0.01 mg/kg/hr), or 4) i.v. infusion of high-dose nicardipine (0.15 mg/kg/hr). The i.v. infusions were started immediately after SAH and continued for 48 hours. Serotonin (5-HT) (10(-8) to 10(-5) mol/L) was used to evoke dose-dependent vasoconstriction of isolated rings of the basilar artery 2 days after SAH. Acetylcholine (ACh) (10(-8) to 10(-4)) and adenosine-triphosphate (ATP) (10(-8) to 10(-4) mol/L) were applied after maximal contraction with 5-HT, evoke a dose-dependent vasodilatation. Compared with controls, in animals subjected to SAH serotonin caused similar or slightly larger contractions; nicardipine infusion did not decrease the amount of contraction observed after SAH. ACh and ATP caused significantly less dilatation in animals submitted to SAH than in controls. After high-dose nicardipine, ACh- and ATP-induced dilatations were significantly more pronounced (57% and 68% of initial contractile tone) than in the other animals receiving SAH (36%-39% and 45%-55%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1992

Clinical outcome of radiosurgery for cerebral arteriovenous malformations.

The clinical outcomes are described for 247 consecutive cases of arteriovenous malformation (AVM) treated with the gamma knife between April, 1970, and December 31, 1983. Headache resolved in 65 (66.3%) of the 98 patients presenting with this symptom and improved in an additional nine (9.2%). Of 59 patients admitted with seizures, 11 (18.6%) became seizure-free without anticonvulsant medication and an additional 30 patients (50.8%) became seizure-free with anticonvulsant medication. Pre-existing neurological deficits improved or totally disappeared following radiosurgery in 56.7% of affected cases. This improvement presumably occurred within the frame of the natural history. The protective effect of the ionizing beams against hemorrhage in incompletely obliterated AVM's is analyzed. To assess the rate of rebleeding, probability estimates were calculated using both the person-year method and the Kaplan-Meier life table. With the person-year method the actual rebleed rate is not too different from the values observed in the natural history of the disease (2% to 3%/yr). Analysis by Kaplan-Meier life-table estimates demonstrated a risk of nearly 3.7%/yr until 60 months after radiosurgery. Five years following treatment, the life table ends in a plateau which could be interpreted as an indication of decrease in the risk of hemorrhage. However, long flat regions at the right end of the life table do not imply that the real risk of rebleeding is negligible unless a large number of patients have been followed well into or beyond the flat region.

Cerebral Hemorrhage↗
PubMed1992

Outcome evaluation in acute neurological injury.

To evaluate outcome one must define the outcome and those factors that contribute to it. Recent advances in measurement of brain injury by radiology, evoked potentials and electroencephalogram (EEG), cerebral blood flow (CBF) and cerebral metabolism have demonstrated differential prognosis. Outcome from coma has also been expanded to include cognitive and neurobehavioral measures as well as functional assessments.

Brain↗
PubMed1991

The effect of nicardipine on vasospasm in rabbit basilar artery after subarachnoid hemorrhage.

This study was performed to examine the effect of the dihydropyridine calcium antagonist, nicardipine, on vasospasm after experimental subarachnoid hemorrhage (SAH) in the rabbit. The study was carried out in two parts: 1) effect of intravenous nicardipine (n = 45) and 2) effect of intracisternal nicardipine (n = 21). SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. In the intravenous study, there were five groups: 1) SAH without treatment; 2) SAH with vehicle (saline); 3) SAH and intravenous infusion of low-dose nicardipine (0.01 mg/kg/h); 4) SAH and intravenous infusion of high-dose nicardipine (0.15 mg/kg/h); and 5) controls without SAH. The intravenous infusions were started immediately after SAH and continued for 48 hours until death. In the intracisternal study, there were three groups: 1) SAH without treatment; 2) SAH with intracisternal administration of nicardipine (0.37 mg/h); and 3) controls without SAH. Intracisternal infusions were begun 70 hours after SAH and continued for 2 hours until death. After perfusion-fixation, the basilar artery was removed and processed for morphometric analysis. In the intravenous study, vessels from animals subjected to SAH were significantly narrowed when compared with controls, although after high-dose nicardipine vessel caliber was slightly larger than in the other SAH groups. Animals given intracisternal nicardipine showed a nonsignificant reduction of caliber as compared with controls: only 12% decrease in diameter and 22% decrease in luminal area. In the rabbit SAH model, nicardipine had a very modest effect on vasospasm at the doses tested.

Animals↗
PubMed1991

Impact of Medicare payment policy on home health resources utilization.

In this study, the association between Medicare regulations and the provision of public home health care is examined. Medicare clients were compared with non-Medicare groups of those 65 years of age or over and those under 65. Results suggested that both age- and payer-related factors contribute to utilization of services. Older patients showed greater need for chronic illness care relative to younger patients; however, Medicare patients used fewer resources and had poorer outcomes relative to older non-Medicare patients.

Adult↗
PubMed1990

Predicting utilization of home health resources. Important data from routinely collected information.

This study examined the feasibility of using routinely collected information on patients enrolled in home health care to predict their subsequent use of services. Data were gathered from 1,984 episodes of care randomly sampled from home health care agencies of the Virginia Health Department. Age, sex, Medicare and Medicaid enrollment, referral source, medical diagnosis, and prognosis were used to predict the total number of visits, the duration of enrollment, and the intensity of service. Since the data were originally gathered to study the effects of the implementation of diagnosis-related groups (DRGs) on home health services, half of the patients were enrolled before and half after the implementation of DRGs. Using multiple linear regression analysis, significant amounts of variance in each measure of home health care utilization were explained by the predictor variables (R2 = 0.04 to 0.10). For example, after controlling for other predictor variables, age 75 years or older predicted longer durations of enrollment and lower intensities of service as compared with other age groups (P less than 0.05), and four of 14 diagnosis categories predicted at least one measure of utilization (P less than 0.05). Medicaid enrollment predicted longer durations of enrollment and lower intensities of service in home health care (P less than 0.05) in the post-DRG but not the pre-DRG period. These results demonstrate the value of routinely collected information in predicting the use of home health services. To develop more accurate estimates of needs for home health services for particular groups of patients, additional information on chronic functional impairments, informal caregiving, and the chronicity of needs may be useful.

Aged↗
PubMed1990

The International Cooperative Study on the Timing of Aneurysm Surgery. Part 1: Overall management results.

The International Cooperative Study on the Timing of Aneurysm Surgery evaluated the results of surgical and medical management in 3521 patients between December, 1980, and July, 1983. At admission, 75% of patients were in good neurological condition and surgery was performed in 83%. At the 6-month evaluation, 26% of the patients had died and 58% exhibited a complete recovery. Vasospasm and rebleeding were the leading causes of morbidity and mortality in addition to the initial bleed. Predictors for mortality included the patient's decreased level of consciousness and increased age, thickness of the subarachnoid hemorrhage clot on computerized tomography, elevated blood pressure, preexisting medical illnesses, and basilar aneurysms. The results presented here document the status of management in the 1980's.

Adolescent↗
PubMed1990

The International Cooperative Study on the Timing of Aneurysm Surgery. Part 2: Surgical results.

A prospective, observational clinical trial was conducted by the International Cooperative Study on the Timing of Aneurysm Surgery to determine the best time in relation to the hemorrhage for surgical treatment of ruptured intracranial aneurysms. Sixty-eight centers contributed 3521 patients in a 2 1/2-year period beginning in December, 1980. Analysis by a prespecified "planned" surgery interval demonstrated that there was no difference in early (0 to 3 days after the bleed) or late surgery (11 to 14 days). Outcome was worse if surgery was performed in the 7 to 10-day post-bleed interval. Surgical results were better for patients operated on after 10 days. Patients alert on admission fared best; however, alert patients had a mortality rate of 10% to 12% when undergoing surgery prior to Day 11 compared with 3% to 5% when surgery was performed after Day 10. Patients drowsy on admission had a 21% to 25% mortality rate when operated on up to Day 11 and 7% to 10% with surgery thereafter. Overall, early surgery was neither more hazardous nor beneficial than delayed surgery. The postoperative risk following early surgery is equivalent to the risk of rebleeding and vasospasm in patients waiting for delayed surgery.

Adolescent↗
PubMed1990

The timing of surgery and vasospasm.

The relationship of time of surgery and vasospasm is influenced by three factors: (1) the time course of vasospasm, (2) the effectiveness of clot removal at surgery, and (3) the choice of medical management to prevent rebleeding and to treat vasospasm. Data to date demonstrate that angiographic vasospasm and vasospasm-related deficits occur in the period from 4 to 14 days after subarachnoid hemorrhage. Surgical intervention in the period of risk for vasospasm is associated with higher morbidity and mortality rates. Morbidity and mortality rates are lowest following surgery in patients who have delayed surgery; however, morbidity and mortality rates for overall management are equivalent for patients with early surgery because of vasospasm and rebleeding in patients waiting for delayed surgery. The surgical removal of the clot may be accomplished in only a limited number of patients, and most series do not reflect a large change in vasospasm occurrence following early surgery. Changes to more aggressive medical therapy in terms of prevention or reversal of ischemia from vasospasm rendered after the aneurysm is clipped and rebleeding is prevented have been initiated during the past decade. The effectiveness and safety of these treatments may play an important future role in the choice of time of surgery and the relationship of time of surgery to vasospasm-related deficits.

Follow-Up Studies↗
PubMed1990

Antifibrinolytic therapy and cerebral vasospasm.

The role of antifibrinolytic drugs in the management of patients with aneurysmal subarachnoid hemorrhage continues to remain uncertain. Recent controlled studies suggest that although these agents may alter the course of the illness, they confer no benefit in terms of overall outcome. Confronted with these data, clinicians in North America have radically altered their management of patients with ruptured aneurysms in the last decade. In the Timing of Surgery Study (1980-1983), 54% of patients were treated with antifibrinolytic drugs and only 32% underwent surgical clipping of the aneurysm on days 0-3 from the subarachnoid hemorrhage. In contrast, only 13% of the patients in the Randomized Trial of Nicardipine in Subarachnoid Hemorrhage (1987-1989) received antifibrinolytics, whereas 53% had early surgery (unpublished observations). Further study will be required to determine if this strategy has resulted in an improvement in overall outcome. Some observers have suggested that as effective therapy for symptomatic vasospasm evolves (e.g., with hypertensive or hypervolemic therapy or calcium antagonists), the adverse effects of antifibrinolytic drugs on brain ischemia may be ameliorated. This idea must be confirmed by further evaluation of the combined use of these treatments. In the interim, antifibrinolytic drugs, if used at all, should be used with caution, and their use should be restricted to those patients judged not to be candidates for early surgery. If therapy cannot be started before day 7 after subarachnoid hemorrhage, it should not be started at all, as the reduced rate of rebleeding after the first 7 days does not justify the increased risk of brain ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrovascular Circulation↗