Observation of pulsed gamma-rays above 25 GeV from the Crab pulsar with MAGIC.

One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 giga-electron volts. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 giga-electron volts, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.

Very-high-energy gamma rays from a distant quasar: how transparent is the universe?

The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.

Variable very-high-energy gamma-ray emission from the microquasar LS I +61 303.

Microquasars are binary star systems with relativistic radio-emitting jets. They are potential sources of cosmic rays and can be used to elucidate the physics of relativistic jets. We report the detection of variable gamma-ray emission above 100 gigaelectron volts from the microquasar LS I 61 + 303. Six orbital cycles were recorded. Several detections occur at a similar orbital phase, which suggests that the emission is periodic. The strongest gamma-ray emission is not observed when the two stars are closest to one another, implying a strong orbital modulation of the emission or absorption processes.

Direct endarterectomy of the middle cerebral artery for treatment of symptomatic stenosis: case report.

The authors report the clinical course and surgical technique used to treat a patient with a high-grade stenosis of the proximal middle cerebral artery that had caused a previous infarction and threatened the remaining dominant hemisphere. Trapping of the involved middle cerebral artery segment allowed direct exposure for excision of the atheromatous plaque and subsequent closure of the arteriotomy. Intraoperative angiography confirmed the reestablishment of flow. The patient made an uneventful postoperative recovery. Direct middle cerebral artery endarterectomy has the advantage of potentially reestablishing flow to lenticulostriate branches. The technique may also avoid the problem of occlusion at the site of maximum stenosis that can be caused by the use of an extra/intracranial bypass graft. Middle cerebral artery endarterectomy is a potentially valuable technique that deserves further investigation.

Transoral-transclival clipping of a giant lower basilar artery aneurysm.

The authors discuss the choice of the transoral-transclival approach for the repair of a lower basilar artery aneurysm in a 32-year-old sickle-cell patient. Efficiency of approach and minimization of damage to vital structures support the use of this technique. The risks of cerebrospinal fluid fistula and meningitis are considered. One year after operation, the patient is neurologically intact.

Transcallosal, transventricular approach to a basilar apex aneurysm.

A new approach to the basilar apex in a patient with a megadolichobasilar anomaly and an abnormally rostral basilar apex aneurysm is described. The details of the surgical approach and the advantages and limitations of this transcallosal, interseptal approach are described.

Direct angioplasty of the basilar artery in baboons.

The lower portion of the basilar artery is a site of significant disease, both aneurysmal and stenotic, but has been considered inaccessible via traditional surgical approaches. A baboon model was used to evaluate the feasibility of a direct surgical reconstruction via a transoral-transclival approach, utilizing temporary occlusion of the basilar artery. An arteriotomy was performed and either repaired primarily or a venous patch graft was sutured in place. All animals survived the surgery; one suffered fatal postoperative upper airway obstruction, but the other four were neurologically intact at the time of death. Patency at the site of repair was confirmed both angiographically and histologically. We conclude that temporary clamping in conjunction with direct reconstruction of the basilar artery is feasible in this primate model. Future studies will focus on further applications of this technique.

Direct repair of an extracranial vertebral artery pseudoaneurysm: case report and review of the literature.

A case of a 47-year-old man with weakness secondary to ossification of the posterior longitudinal ligament is presented. During removal of the ossified ligament, the patient's dominant right vertebral artery was injured. Although the bleeding from this artery was controlled intraoperatively, the patient developed an expanding cervical hematoma on the 3rd postoperative day. An angiogram demonstrated a large pseudoaneurysm of the right vertebral artery. The patient was taken back to the operating room where the cervical hematoma was removed, and direct repair of the pseudoaneurysm of the vertebral artery was performed. The previously reported cases of pseudoaneurysms of the extracranial vertebral artery are reviewed. We advocate the use of direct vascular repair as the treatment of choice in these lesions.

Prolongation of survival for high-grade malignant gliomas with adjuvant high-dose BCNU and autologous bone marrow transplantation.

Employment of postoperative brain irradiation in the initial management of high-grade malignant glial tumors has now become standard. The addition of conventional chemotherapy to irradiation has not significantly improved median survival beyond 1 year. We treated 25 consecutive patients (13 pilot patients and 12 protocol patients) with histologically confirmed unresectable grade 3 or 4 malignant gliomas with high-dose BCNU (carmustine) followed by autologous bone marrow transplantation and whole brain irradiation. Within 3 weeks of initial surgery, each patient had autologous bone marrow stored (median 2 X 10(8) nucleated cells/kg), and then received BCNU 1,050 mg/m2 intravenously (IV). Peripheral granulocytes recovered (greater than 500/microL) at a median of 19 days (range, 10 to 37 days), and platelets recovered (greater than 20,000/microL) at a median of 18 days (range, 13 to 40 days), following bone marrow infusion. Patients received 60 Gy whole brain irradiation when granulocytes were greater than 1,500/microL. Toxicity was well tolerated. Nausea occurred in 19 patients (76%); however, only eight patients (32%) experienced vomiting (mild in three, moderate in five). Eleven patients (44%) did not require empiric antibiotics, six of whom never developed an absolute granulocyte count less than 500/microL. Three patients with a poor performance status died early (one seizure with vomiting and asphyxiation; one, klebsiella urinary tract infection (UTI) with bacteremia; one, candidal pneumonia), and one additional patient who was performing well died of pulmonary hemorrhage. The 13 pilot patients have now been followed for a median of 23 months, with a significant survival advantage compared with the 52 consecutive historical control patients who received similar surgery and radiotherapy without high-dose BCNU (P = .037). The overall study group of 25 patients also has a significant survival advantage when compared with the same historical control group, with a projected median survival of 26 months (P = .007). This new approach using early postoperative intensive therapy consisting of high-dose BCNU, autologous bone marrow transplantation, and whole brain irradiation appears to significantly improve survival.

Current concepts in clinical therapeutics: ischemic cerebrovascular disease.

The classification, epidemiology, pathophysiology, diagnosis, and treatment of ischemic cerebrovascular disease (ischemic stroke) are reviewed, and the major drugs used in the prevention of this disease are discussed. Ischemic stroke is a major problem in terms of morbidity and mortality because of the high prevalence of atherosclerosis in the United States population. The pathogenesis of cerebral ischemia is multifactorial, beginning with an atherosclerotic plaque on the arterial wall that may result in stenosis or ulceration with subsequent thrombosis or embolization. Platelets may adhere to the exposed arterial wall endothelium, stimulating further platelet aggregation and accumulation of leukocytes and fibrin. Consequences of cerebral ischemia include transient ischemic attacks and brain infarcts. Diagnosis is based mainly on patient history and ancillary radiologic studies. Treatment of ischemic cerebrovascular disease is primarily preventive, since the brain has limited capacity to recover neurologic function after an infarction. Transient ischemic attacks are treated with either antiplatelet agents, anticoagulants, or surgery. Treatment of stroke is also preventive, although anticoagulation is sometimes used to prevent stroke progression. Agents that may reverse neurologic impairment following an acute stroke, such as prostacyclin, calcium-channel blockers, and opiate antagonists, are being investigated. Antiplatelet therapy is indicated in subsets of patients with cerebral vascular insufficiency. Anticoagulation therapy, if needed, should be given for only three to four months.

Temporalis myofascial repair of traumatic defects of the anterior fossa. Technical note.

Bilateral temporalis myofascial flaps in continuity with frontal periosteum can be used in repairing extensive dural and bone defects of the anterior cranial fossa floor. The technique of preserving and using this flap is described and offers an alternative to the use of frontal pericranial tissue for repair of anterior dural defects.

Acute cerebral revascularization.

Fifteen patients evaluated for acute cerebral ischemia underwent acute cerebral revascularization between March, 1979, and May, 1983. Clinical presentation included crescendo transient ischemic attacks (TIA's) in eight cases, progressing neurological dysfunction in three cases, and completed nonfluctuating deficits in four cases. Nine patients received intravenous heparin but did not improve neurologically. The patients with crescendo TIA's were operated on within 4 hours of their last event; those with progressing deficits were operated on while the deficit was developing, and those with established deficits were operated on 4, 6, 9, and 12 hours, respectively, after the event began. The clinical picture for 10 patients had resolved within 10 hours after surgery. One patient with crescendo TIA's, two with progressing deficits, and two with established deficits had postoperative residual deficits, of which three were mild and two severe. One patient, who had a saphenous vein graft to the middle cerebral artery, developed an intracerebral hematoma. In this prospective noncontrolled nonrandomized study, acute cerebral revascularization was performed safely, had limited risks, and offered the potential to help some patients. Further controlled randomized studies are indicated.

Surgical reconstruction of the proximal vertebral artery.

The authors have reviewed their experience in the management of 55 patients admitted to Henry Ford Hospital with symptoms of vertebrobasilar insufficiency and associated proximal vertebral artery stenosis or occlusion. In 48 patients, the symptoms occurred as multiple repeated events, five of which resulted in permanent deficits. The remaining seven patients had single events, four of which caused permanent deficit. These patients had been treated unsuccessfully with antiplatelet agents (37 cases) and with anticoagulant drugs (15 cases) before surgery. Most patients had multiple angiographic abnormalities, including bilateral vertebral stenosis in 19 cases, unilateral vertebral stenosis and contralateral occlusion in 18, unilateral vertebral hypoplasia and contralateral stenosis in 10, subclavian artery stenosis with steal in seven, and bilateral vertebral artery occlusion in one case. Posterior communicating arteries could not be demonstrated angiographically in 18 patients. Thirty-four patients had associated stenotic or occlusive lesions of the internal carotid artery. Forty-eight underwent a vertebral-to-carotid artery transposition. Of these, 18 had an associated carotid endarterectomy and seven had a vertebral artery endarterectomy immediately before the transposition. Two patients had saphenous vein grafts, one from the subclavian and one from the common carotid artery to the vertebral artery. Other surgical procedures included vertebral artery ligation in one case, transposition of the vertebral artery to the thyrocervical trunk in two cases and to the subclavian artery in one case, and endarterectomy of the origin of the vertebral artery in one case. All but two patients had complete resolution of their symptoms: one had persistent dizziness and the other had syncopal episodes. Complications included transient Horner's syndrome (30 cases) which became permanent in four cases, vocal cord paralysis (three cases), elevated hemidiaphragm without respiratory difficulty (two cases), and superficial would infection (one case). There were no deaths. Although the presentation of patients with vertebrobasilar insufficiency is generally characteristic, we believe that a specific diagnosis can be established only by angiographic means. Anticoagulants have been used to alleviate symptoms in some cases but are ineffective in solving the primary hemodynamic problem. Surgical reconstruction of the affected area deserves further evaluation in the management of these patients.

Pharmacologic management of acute intracranial hypertension.

Acute intracranial hypertension requires aggressive treatment with physiologic and pharmacologic measures guided by intracranial pressure monitoring devices. Therapy involves the use of diuretics, corticosteroids, and barbiturates in combination with hyperventilation, ventricular drainage, and general supportive measures. This review focuses on the pathophysiology of increased intracranial pressure and the pharmacologic agents used in its management.

Combined reconstruction of the vertebral and carotid artery in one single procedure.

Patients suffering from vertebrobasilar insufficiency frequently have multiple areas of involvement in the extracranial circulation. Eight patients admitted to Henry Ford Hospital had symptoms suggestive of vertebrobasilar insufficiency and angiograms showing multiple abnormalities. A combined operation that reconstructed the carotid and vertebral circulations in one single procedure was completed in all patients with minimal morbidity and no mortality. The surgical procedure is described in detail.

Comprehensive services at Fabella Center.

PIP: The Jose Fabella Memorial Hospital Comprehensive Family Planning Center was the 1st family planning center to conduct minilaparotomy in the Philippines. It was also the 1st center to conduct research on family planning and to offer training in family planning to nurses, doctors, midwives, and medical students. The center is funded by the Philippine government with about 85% of hospital funds going to salaries of the staff. Supplementing the funding are medicine, equipment, and subsidies for sterilization given by the Commission on Population (Popcom). Research on chemical sterilization requires patients to take oral contraception (OC) or use the condom while under observation for about 4 months. In the case of female patients, this means until the fallopian tubes have been blocked due to the injection of an opaque solution. The patients are then checked for effects on health, sexual practices, and the regularity of menstruation. Dr. Apelo expects to implement this new sterilization method within 5 years. The center's objective is to support the National Population Program in its effort to reduce the country's population growth rate and promote family welfare. When the center was started, it occupied only 1 room of the hospital and was staffed by 1 full time doctor, 4 nurses, 4 midwives, 2 social workers, and 3 support staff. After 1 year of operation, the center recruited only 75 family planning acceptors. Information about the center's family planning services spread solely by word of mouth. During the 1st half of 1982, the center recruited 3490 acceptors of surgical and nonsurgical contraception, representing 96.94% of its 3600 target for the period. Minilaparotomy had the highest number of acceptors, 1742 or 49.92% of the total number of acceptors during the period. This was followed by the IUD with 1356 acceptors, OC, 245 acceptors; and other methods, 147 acceptors. In information and education, the center had 1882 motivational activities consisting of group discussions, ward lectures, field lectures, and mothers' classes. In training, the center conducted 10 courses, representing 100% of its target for the whole year. It trained doctors in performing voluntary surgical contraception and paramedics in assisting doctors in sterilization operations. The training courses were conducted under a subsidized contract with Popcom. The center also offers training in IUD insertion. In research, the center is active in investigating prospects for new contraceptive applications in the Philippine setting.^ieng