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Biomedical subjects

J C Torner

Publications and source records attributed to J C Torner.

107 records · Page 6Linked to original sources
PubMed1981

Early management of aneurysmal subarachnoid hemorrhage. A report of the Cooperative Aneurysm Study.

The overall results are presented of early medical management and delayed operation among 249 patients studied during the period 1974 to 1977, treated within 3 days of subarachnoid hemorrhage (SAH) and evaluated 90 days after aneurysm rupture. The results included 36.2% mortality, 17.9% survival with serious neurological sequelae, and 46% with a favorable outcome. Of the patients admitted in good neurological condition, 28.7% had died and only 55.7% had a favorable recovery at 90 days after SAH. These figures represent the results despite effective reduction in early rebleeding by antifibrinolytic therapy and successful surgery in those patients reaching operation. Further therapeutic advances are needed for patients hospitalized within a few days after SAH.

Antifibrinolytic Agents↗
PubMed1981

Preoperative prognostic factors for rebleeding and survival in aneurysm patients receiving antifibrinolytic therapy: report of the Cooperative Aneurysm Study.

Prognostic factors for mortality and recurrent hemorrhage in the preoperative, 2-week period were determined in 1114 patients who participated in the antifibrinolytic therapy investigations of the Cooperative Aneurysm Study between 1970 and 1977. Factors significantly related to mortality were admission neurological status, diastolic blood pressure, interval to treatment, degree of vasospasm, and medical condition. Factors associated with the likelihood of recurrent hemorrhage were interval to treatment, patient's sex, and admission neurological status. These factors need to be considered in the analysis of clinical data in the management of ruptured intracranial aneurysms.

Adolescent↗
PubMedDate not supplied

Why are African Americans under-represented in medical research studies? Impediments to participation.

OBJECTIVES: In accordance with the NIH Revitalization Act of 1993, the National Institutes of Health and the Alcohol, Drug and Mental Health Administration require grant applicants and cooperative agreement participants to include minorities in human subject research. In an environment characterized by diminishing research dollars, this mandate has increased the pressure on investigators to determine factors that impede minority participation and to develop strategies to overcome these impediments. METHODS: An extensive review of the literature was conducted to identify the factors possibly responsible for the low participation levels of African Americans in medical research studies and to highlight areas for further research. The items examined included the historical relationship between African Americans and medical researchers and the attitudes, perceptions and beliefs of potential participants and researchers as they relate to the low representation of African Americans in medical research. RESULTS: The factors identified as possible impediments to African American participation included distrust of the medical/scientific community, poor access to primary medical care, the failure of researchers to recruit African Americans actively, the alienation of minority health professionals, lack of knowledge about clinical trials, language and cultural barriers. CONCLUSIONS: Well-designed, relevant, ethical research in conjunction with an appreciation of the many barriers to participation are paramount to increasing African American presence in clinical research.

Black or African American↗
PubMedDate not supplied

Self-reported postwar injuries among Gulf War veterans.

OBJECTIVE: From September 1995 to May 1996, the authors conducted a telephone survey of Iowa military personnel who had served in the regular military or activated National Guard or Reserve during the Gulf War period. To assess the association between military service in a combat zone and subsequent traumatic injury requiring medical consultation, the authors analyzed veterans' interview responses. METHODS: Using data from the larger survey, the authors compared rates of self-reported postwar injuries requiring medical consultation in a sample of Iowa Gulf War veterans to the rates in a sample of Iowa military personnel who served at the same time, but not in the Persian Gulf. RESULTS: Of 3695 veterans, 605 (16%) reported a traumatic injury in the previous three months requiring medical consultation. Self-reported injuries were associated with service in the Persian Gulf (odds ratio 1.26; 95% confidence interval 1.02, 1.55). CONCLUSION: This finding is consistent with the results of earlier studies of traumatic injury mortality rates among war veterans.

Adult↗
PubMedDate not supplied

Influence of timing of admission after aneurysmal subarachnoid hemorrhage on overall outcome. Report of the cooperative aneurysm study.

The overall management results after aneurysmal rupture were studied in 158 patients admitted to the hospital on day 0--3 and 175 patients admitted on day 4--7 following subarachnoid hemorrhage. In this series surgery was planned no sooner than 12 days following the ictus. Despite effective medical and surgical therapy overall results were disappointing: 3 months following the initial hemorrhage only 43% of patients in the 0--3 day group and 53% of patients in the 4--7 day group were capable of independent functional living. Patients admitted on days 4--7 also had a lower mortality rate, re-bled less frequently, and had lower postoperative mortality and morbidity than those admitted on days 0--3. For reasons not well defined, time of admission following aneurysmal SAH has an important influence on outcome. Accordingly, in evaluating outcome for patients with ruptured aneurysms treated with different therapeutic modalities, time of admission must be carefully controlled.

Female↗
PubMedDate not supplied

The International Cooperative Study on Timing of Aneurysm Surgery--an update.

The timing of aneurysm surgery is one of the major controversies in the management of subarachnoid hemorrhage. The Cooperative Aneurysm Study is conducting an international epidemiological study to determine mortality and morbidity related to timing of surgery. From January, 1981 to July, 1983 over 3,500 patients have been registered from 68 centers. This preliminary report updates the progress of the study, describes the patient population, and presents overall outcome results.

Female↗
PubMedDate not supplied

Pharmacological comparison of isolated monkey and dog cerebral arteries.

Pharmacological differences between canine and monkey basilar arteries were studied in vitro. The constrictor response of canine basilar artery to either norepinephrine or an alpha 1-adrenoceptor agonist phenylephrine was partly inhibited by an alpha 2-adrenoceptor antagonist yohimbine but not by an alpha 1-adrenoceptor antagonist prazosin. The contraction elicited by an alpha 2-adrenoceptor agonist clonidine was inhibited by neither prazosin nor yohimbine. These results suggest that the receptors in canine basilar artery which mediate norepinephrine-induced contraction are different from classical alpha 1 or alpha 2-adrenoceptors, although they more closely resemble the alpha 2- rather than the alpha 1-subtype. Using monkey basilar artery, phenylephrine produced the same amplitude of maximum contractile response as norepinephrine, though a much higher concentration of phenylephrine than norepinephrine was needed in order to elicit that maximum response. Clonidine did not elicit contractions. The contraction induced by norepinephrine was markedly suppressed by both prazosin and yohimbine in a noncompetitive fashion. The constrictor response of monkey basilar artery to norepinephrine, therefore, appears to be mediated by alpha 1-like adrenoceptors. Comparison of ED50 values for thromboxane A2 revealed that the monkey basilar artery was more sensitive to thromboxane A2 than that of the canine. Prostaglandin F2 alpha produced a larger maximum contraction in monkey basilar arteries than in canine basilar arteries, although the ED50 values for monkey basilar arteries were larger than those for canine basilar arteries. The ED50 values for serotonin in canine basilar arteries were a little less than those for monkey basilar arteries, although both arteries produced nearly identical maximum contractions.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Delay in referral of patients with ruptured aneurysms to neurosurgical attention.

Aneurysmal subarachnoid hemorrhage is a neurosurgical emergency. Early medical intervention is axiomatic for minimizing rebleeding and ischemia from vasospasm and achieving optimum results. The purpose of this study was to document the length and causes of the delay in referral which occur in patients following aneurysmal subarachnoid hemorrhage. The case histories of 150 consecutive patients admitted to The University of Iowa with proven ruptured aneurysms were studied. Medical records from The University of Iowa and referring hospitals were reviewed, and patients, families, and referring physicians interviewed. Overall, only 36% were referred within 48 hours of their first clear cut, recognizable sign or symptom of subarachnoid hemorrhage. Median time to referral was 3.6 days. Delay was due to physician diagnostic problems in 37%, delayed referral policy in 23%, unstable patient condition in 7%, failure of patients to recognize severity of illness in 8%, and logistical reasons in 12%. These data suggest that a large proportion of patients have a delay in achieving definitive neurosurgical care following aneurysm rupture, and that for the most part this delay is avoidable. More emphasis must be placed on public health and primary physician education regarding subarachnoid hemorrhage.

Diagnostic Errors↗
PubMedDate not supplied

The effects of hyperosmolar solutions on cerebral arterial smooth muscle.

The present study was conducted to clarify the effect of hyperosmolar solutions on the constrictor responses of cerebral arteries to vasoactive agents, in vitro. The canine basilar arteries under resting tension were slightly relaxed with both mannitol (0.5, 1 and 2%) and sucrose (1, 2, and 4%). Constrictor responses of canine basilar arteries to 40 mM K+, 10(-7) M serotonin or 10(-6) M prostaglandin F2 alpha (PGF2 alpha) were markedly suppressed by pretreatment with either mannitol or sucrose. The rate of suppression correlated well to osmolarity changes in the Kreb's solution. When the specimens were incubated in Ca++-free medium, 10(-6) M PGF2 alpha elicited small contractions. Addition of 1 mM Ca++ to the bath promptly elicited larger contractions. The large contractions in response to the influx of extracellular Ca++ were markedly suppressed by pretreatment with mannitol or sucrose, while the small contractions induced by intracellular Ca++ were not inhibited. In addition, the contractions induced by the addition of Ca++ to the specimens depolarized with 80 mM K+ in Ca++-free medium were dose-dependently inhibited with either mannitol or sucrose, while the caffeine-induced contractions in Ca++-free medium were not altered by mannitol. These results suggest that hyperosmolar solutions produce non-specific vasodilation of cerebral arteries by inhibiting the influx of external Ca++ rather than the release of intracellularly stored Ca++. This direct vasodilatory effect may account in part for the transient increase of cerebral blood flow following administration of hyperosmolar mannitol.

Animals↗
PubMedDate not supplied

Impairment of endothelium-dependent vasodilation induced by acetylcholine and adenosine triphosphate following experimental subarachnoid hemorrhage.

The effect of subarachnoid hemorrhage (SAH) on endothelium-dependent vasodilation of isolated rabbit basilar artery was examined using an isometric tension recording method. Thirty-five rabbits that had 2 successive blood injections were divided into 3 groups: normal animals (control), 4 days, and 3 weeks after the first SAH. Acetylcholine (ACh) (10(-6)-10(-4) M) and adenosine triphosphate (ATP) (10(-6)-10(-4) M) were used to evoke dose-dependent vasodilation of isolated arterial rings previously contracted by 10(-6) M serotonin. In the animals killed 4 days after the first SAH, both ACh- and ATP-induced relaxation were suppressed, and the degree of relaxation of this group was 38 +/- 4.5% (mean +/- SEM) and 22 +/- 3.9% of the initial contractile tone in response to 10(-4) M ACh and 10(-4) M ATP, respectively. Suppression of the relaxation induced by ATP was seen even in the animals killed 3 weeks after the first SAH. Moreover, pretreatment with hemoglobin (10(-6) and 10(-5) M) inhibited endothelium-dependent vasodilation induced by ACh in the arterial rings from the animals killed 4 days after the first SAH. The present experiments suggest that impairment of the endothelium-dependent vasodilation following SAH may be involved in the pathogenesis of cerebral vasospasm.

Acetylcholine↗
PubMedDate not supplied

Intracranial aneurysms and subarachnoid hemorrhage. A cooperative study. Antifibrinolytic therapy in recent onset subarachnoid hemorrhage.

In this cooperative study among 13 institutions, 502 patients were treated with antifibrinolytic medication (epsilon-aminocaproic acid or tranexamic acid) within a 14-day period following rupture of an intracranial aneurysm. Mortality at the end of 14 days was 11.6%; proved rebleed rate was 12.7%. Patients with an internal carotid or anterior cerebral aneurysm had the highest mortality and rebleed rate. Most rebleeds occurred between the sixth and eleventh days following the initial bleed. Significantly higher mortality was reported among patients with cerebral vasospasm, yet rebleed rate was no different among those patients with or without vasospasm. The same pattern was observed among patients with a mean blood pressure value above and below 110 mm Hg. We conclude that antifibrinolytic therapy provides beneficial treatment to patients with recent onset subarachnoid hemorrhage (SAH) following rupture of an intracranial aneurysm.

Age Factors↗
PubMedDate not supplied

Intracranial aneurysms and subarachnoid hemorrhage - report on a randomized treatment study. IV-A. regulated bed rest.

Three weeks of regulated bed rest was one of four treatments evaluated in the Cooperative Aneurysm Study. A total of 187 patients with a recently ruptured intracranial aneurysm had subarachnoid hemorrhage confirmed by lumbar puncture. A group of 124 patients were assigned to treatment within 7 days after the bleed, 49 between 8 and 21 days, and 14 between 22 days and 92 days. During the mean follow-up interval of 6.5 years, mortality was 55.1%. A proved rebleed was the cause of death in 34.2%, progressive deterioration from aneurysm rupture in 8.0%, and a suspected rebleed in 4.8%. A total of 47.1% died of causes related directly to the cerebral effects of the ruptured aneurysm.

Adolescent↗
PubMedDate not supplied

Patient characteristics and pre-operative therapeutic modalities.

The International Cooperative Study on the Timing of Aneurysm Surgery included 68 participating centers from 16 different countries. Eight Italian neurosurgical units participated in the Study: Bellaria Hospital, Bologna; Neurological Institute of Milan, Milan; University Hospital, Brescia; University of Milan, Milan; University of Padova, Padova; University of Rome, Rome; Civil Hospital, Verona; and Civil Hospital, Vicenza. The overall case contribution from the Italian centers was 485 cases, 14.1% of the total study population. As compared to the other centers included in the Study, the Italian centers exhibited a higher percentage of patients with impaired consciousness; a later interval of planned surgery from SAH; frequent use of preoperative lumbar drainage, as well as antihypertensives, anticonvulsants, antifibrinolytics, steroids, diuretics and LMW dextran; and less frequent use of sedatives and narcotics. The individual Italian centers differed significantly in regard to patient characteristics and preoperative therapeutic modalities. There was a relatively high number of stuporous or comatose patients admitted to Centers 1, 7 and 8, very few admitted to Centers 5 and 6, and none admitted to Center 2. The different distribution of key prognostic factors prevents a direct comparison of the overall management results of the centers. A stratification of the patients according to a risk scale and/or a prognostic model is required for comparison of the management results.

Female↗
PubMedDate not supplied

Surgical findings and postoperative therapeutic modalities.

The 8 Italian centers participating in the International Cooperative Study on Timing of Aneurysm Surgery operated upon 68% of their patients eligible for the study. This low operative rate is mainly explained by the prevailing use of a delayed surgical policy. Only 28% of cases were operated on within 3 days of hemorrhage. Although early surgery was applied in more than 50% of patients from Centers 2, 6 and 7, most other centers operated on approximately 10% of patients within this time interval. Italian centers exhibited a wide variation in planned and actual surgery interval, with only 48% of their patients eventually operated on at the planned time. Differences from planned and actual timing of surgery were less consistent in the units performing early surgery. Preoperative conditions were different between the individual centers. The percent of patients alert at the time of surgery varied from approximately 50% in Centers 3 and 7 to 90% in Center 5. Centers 2 and 6 never operated on comatose patients and rarely stuporous patients. During surgery, induced hypotension was used in 67% of Italian patients. The brain was tight at exposure in 42% of patients from Italian centers; the difference from the other study centers was very significant (p = 0.0009). Consequently major brain resection was more frequently performed in Italy than in the other centers. Brain conditions depended mainly upon timing of surgery and preoperative grade (except for comatose patients) and varied accordingly between the individual centers. Temporary arterial occlusion was rarely used in Italian centers. Intraoperative bleeding from the aneurysm was slightly more frequent than in the other centers. The overall incidence of intraoperative complications was unremarkable. There were significant differences between the Italian and the other centers regarding the use of postoperative routines and medications. In Italian centers ventricular CSF drainage, shunt insertion, ICP monitoring, sedatives and analgesics were less frequently used; lumbar CSF drainage, anticonvulsants, steroids, and diuretics were applied more frequently. In the individual centers the major differences were in the use of antihypertensives, vasopressor agents, diuretics, hypervolemia, and low-molecular weight dextran.

Humans↗
PubMedDate not supplied

Results of treatment.

Overall results of management in patients admitted to the 8 Italian centers participating in the International Cooperative Study on Timing of Aneurysm Surgery were rather unsatisfactory, with good recovery in only 42% of patients, and death in 45% of patients. As compared to the other centers included in the Study, Italian centers exhibited a significantly lower recovery rate and a significantly higher mortality rate. There were significant differences also between the individual Italian centers; independently of admission neurological status and timing of surgery, the outcome was better in centers 2 and 6 (a mortality rate under 20%) and worse in centers 1 and 8 (a mortality rate around 60%). Using prognostic factor models, higher than expected mortality rates were observed in 4 centers, and lower than expected good recovery rates in 3 centers. In Italian centers vasospasm accounted for the highest morbidity and mortality rate; the difference in mortality rate from vasospasm between Italian and other centers was very significant. Other important causes of death and disability were constituted by direct effect of the initial bleed and by recurrent hemorrhage. Patients operated on in Italian centers exhibited a good recovery in 57% of cases; the mortality was 27%. Differences from the other centers were less marked than for the overall management results. Mortality rates from vasospasm and from surgical complications were significantly higher in Italian than in the other study centers. Between the individual Italian centers, vasospasm accounted for the highest mortality rate in centers 7 and 8 (17% and 28% respectively). Postoperative pneumonia was significantly more frequent in Italian than in the other centers. In regard to timing of surgery, the differences in results between Italian and other centers were less marked when surgery was performed after 10 days from hemorrhage. In Italian centers as a whole, a delayed operation was linked with a better outcome than an early or subacute operation. The lowest recovery rate was observed in drowsy patients operated on between 4 and 10 days from the hemorrhage. Focal ischemic deficits and pneumonia were prevalent after an operation within 3 days of hemorrhage, while postoperative brain swelling was most frequent in patients operated on between 4 and 10 days from hemorrhage. The differences in results between Italian and other centers and among the individual Italian centers are widely discussed; possible explanations include inadequate modalities of treatment (especially inadequate management of vasospasm) and structural deficiencies of intensive care management in seriously ill patients.

Humans↗