Maximizing US nitrate removal through wetland protection and restoration.

Growing populations and agricultural intensification have led to raised riverine nitrogen (N) loads, widespread oxygen depletion in coastal zones (coastal hypoxia)1 and increases in the incidence of algal blooms.Although recent work has suggested that individual wetlands have the potential to improve water quality2-9, little is known about the current magnitude of wetland N removal at the landscape scale. Here we use National Wetland Inventory data and 5-kilometre grid-scale estimates of N inputs and outputs to demonstrate that current N removal by US wetlands (about 860 ± 160 kilotonnes of nitrogen per year) is limited by a spatial disconnect between high-density wetland areas and N hotspots. Our model simulations suggest that a spatially targeted increase in US wetland area by 10 per cent (5.1 million hectares) would double wetland N removal. This increase would provide an estimated 54 per cent decrease in N loading in nitrate-affected watersheds such as the Mississippi River Basin. The costs of this increase in area would be approximately 3.3 billion US dollars annually across the USA-nearly twice the cost of wetland restoration on non-agricultural, undeveloped land-but would provide approximately 40 times more N removal. These results suggest that water quality improvements, as well as other types of ecosystem services such as flood control and fish and wildlife habitat, should be considered when creating policy regarding wetland restoration and protection.

Meningiomas induced by high dose cranial irradiation.

The authors present four patients with a history of high dose cranial irradiation, who were diagnosed years later to have symptomatic meningiomas requiring surgical management. Relevant literature pertaining to these rare tumours is reviewed and their unusual characteristics highlighted. Their aetio-pathogenesis and management strategies are discussed.

Transradicular interfascicular approach for lumbar microdiscectomy: a useful technique in difficult circumstances.

Nerve root retraction is a component of lumbar disc surgery. The authors describe a transdural approach for lumbar microdiscectomy through the nerve root, instead of retracting the root. This technique can be safely used in rare cases where root manipulation is considered to be difficult and dangerous.

Spontaneous regression of a primary cerebral tumour following postoperative middle cerebral artery territory infarction.

Gliomas are incurable cerebral tumours. Surgery with adjuvant therapy is aimed at achieving a maximum symptom-free period. We report a case of spontaneous regression of a cerebral oligodendroglioma following infarction in the territory of its feeding artery. Prospects of interventional technique as a part of multimodality treatment of gliomas are discussed.

Stressful events, pessimism, natural killer cell cytotoxicity, and cytotoxic/suppressor T cells in HIV+ black women at risk for cervical cancer.

OBJECTIVE: This study examines whether stressful negative life events and pessimism were associated with lower natural killer cell cytotoxicity (NKCC) and T cytotoxic/suppressor cell (CD8+CD3+) percentage in black women co-infected with human immunodeficiency virus Type 1 (HIV-1) and human papillomavirus (HPV), a viral initiator of cervical cancer. METHOD: Psychosocial interviews, immunological evaluations, and cervical swabs for HPV detection and subtyping were conducted on 36 HIV+ African-American, Haitian, and Caribbean women. RESULTS: Greater pessimism was related to lower NKCC and cytotoxic/suppressor cells after controlling for presence/absence of HPV Types 16 or 18, behavioral/lifestyle factors, and subjective impact of negative life events. CONCLUSIONS: A pessimistic attitude may be associated with immune decrements, and possibly poorer control over HPV infection and increased risk for future promotion of cervical dysplasia to invasive cervical cancer in HIV+ minority women co-infected with HPV.

A late, fatal complication of a high energy thermal injury to the scalp.

Marjolin's ulcer is an uncommon condition in which malignant transformation occurs in a chronic inflammatory focus. It was originally described in association with a thermal injury, however, its occurrence with protean chronic inflammatory foci has been described. We report the occurrence of and aggressive squamous carcinoma 3 decades after a high voltage electric mark injury to the scalp. This is the first such case described in the literature. The case supportively highlights the role of chronic inflammation and sepsis in epidermal scar cancer development, and it underlines the importance of appropriate wound management initially and expeditious treatment of sepsis and resistant skin ulceration because the malignant behavior of these tumors is aggressive and unpredictable.

Use of the Injury Severity Score in head injury.

As part of a study of the early management of severe head injury, the use of the Glasgow Coma Score (GCS), Injury Severity Score (ISS) and TRISS was investigated. These injury scores were compared in correlating with outcome at one year as assessed by the Glasgow Outcome Score (GOS) and mortality. One hundred and thirty-one patients had a severe head injury, as defined by an ISS of 16 or higher, in whom the Abbreviated Injury Score (AIS) for craniocerebral injury was 3 or higher. Seventy-eight of these also fulfilled the accepted GCS definition of severe head injury (GCS less than 8 with no eye-opening). Thirty-eight had evacuation of an acute intracranial haematoma; 26 of these patients would not have been classified as severe head injury by GCS. The overall mortality rate was 38 per cent, and 24 per cent for those transferred to the neurosurgical unit. TRISS was slightly better than GCS for predicting outcome based on both GOS and mortality, however this difference was not significant. TRISS identified patients who died that are not considered as severe head injury by GCS. Use of TRISS allows the effects of systemic factors and other injuries to be taken into account when assessing severity of head injury.

Early management of severe head injury in Northern Ireland.

As part of a study into the management of major trauma, the early management of severe head injury in Northern Ireland was evaluated over a 12-month period. The injury severity score was used to define those patients considered to have severe head injury. There were 131 patients with severe head injury; 27 per cent were hypoxic and 18 per cent were hypotensive on admission to the primary hospital. Almost half had severe multiple injuries. Early endotracheal intubation was performed in 92 per cent of comatose patients, and adequate resuscitation (including laparotomy in some) was performed in 87 per cent of shocked patients transferred to the neurosurgical unit (NSU). Eighty patients were transferred to the NSU; 60 per cent were comatose, 68 per cent were intubated and ventilated, and 74 per cent were transferred by an anaesthetist. Two patients were in hypovolaemic shock after transfer and required laparotomy. Thirty-eight had evacuation of an acute intracranial haematoma; 26 of these would not have been classified as severe head injury by the Glasgow coma scale. The overall mortality rate was 38 per cent, and 24 per cent for those transferred to the NSU. We conclude that the early management of head injury in Northern Ireland is good, but there are problems, including pre-hospital oxygenation and delays in transfer.

Management of severe spasticity with intrathecal baclofen delivered by a manually operated pump.

Intrathecal baclofen abolishes spasticity in many patients with neurological diseases but there are few studies on its long-term effectiveness. Since 1986 a manually operated subcutaneous pump has been used to deliver baclofen intrathecally in 21 patients with a follow up of at least one year. Most patients had multiple sclerosis and all were wheelchair-bound. Sixteen patients had a complete and sustained benefit. In four other patients the treatment was effective in the short term but not in the long term. In the remaining patient the pump never worked. Complications included meningitis, pump failure, erosion through the skin, and baclofen overdose. Nevertheless, only three patients have asked to discontinue the treatment. We conclude that intrathecal baclofen, delivered by a manually operated implanted pump, is an effective treatment for severe spasticity in most patients.

The presence of tumour necrosis factor in CSF and plasma after severe head injury.

In a cohort of victims of traumatic brain injury, 18 out of 50 patients had a plasma tumour necrosis factor (TNF) concentration above 2 pg/ml within 24 h of injury (mean 12.19, SD 45.96 pg/ml). Twenty-six had CSF samples available of which 17 demonstrated TNF concentrations above 1 pg/ml (mean 3.98, SD 3.61 pg/ml). We conclude that traumatized brain parenchyma is a significant source of TNF activity and implicate the cytokine in cellular metabolic derangements following head injury.

Bilateral acoustic neuromas.

This article reviews 12 patients with bilateral acoustic neuromas. The sex incidence was equal and the mean age at diagnosis was 26.2 years. The family history was positive in nine of the patients. Five patients have had incomplete surgical removal of acoustic neuromas on both sides. Two of them are completely deaf and the other three have severe sensorineural hearing loss in one ear and no hearing in the other ear. In five patients the tumour on one side has been operated on and the other side is being observed with at least short-term preservation of good hearing. The remaining two patients died of intra-cranial complications, one of them post-operatively. Four patients developed facial palsy immediately following surgery and one developed facial weakness 6 months after surgery. Guidelines are discussed for the care of these patients including the timing of surgery and alternative treatment options (observation, radio-surgery and chemotherapy). This is essentially a group of young individuals who have had multiple operations for bilateral acoustic tumours and associated manifestations and for whom the disease and the sequelae of treatment can be tragic.

Non-surgical management of acoustic neuromas.

Watchful waiting is one of the options available in the management of acoustic neuromas and this article deals with 13 patients who were so managed. Non-operative management was advised because of age, poor general health, small size of tumour, only hearing ear, or in patients unwilling to undergo surgery for various reasons. This group was followed up at 6-12-monthly intervals and the follow-up period ranged from 1 to 18 years (mean 5.3 years). Ten patients had small tumours and only in 2 of these was increase in tumour size demonstrated on follow-up CT scan. In one this increase was later followed by regression. Two patients required partial removal of tumour because of increasing symptoms after 3 and 7 years of follow-up; one of them died on the twelfth post-operative day. There appears to be a small group of patients for whom delay is worth while rather than to subject all patients with acoustic neuroma to surgery from which full recovery cannot be guaranteed.

Acoustic neurinoma surgery in Belfast 1986-1989.

Forty-seven acoustic neurinoma tumours have been operated on in 46 patients in the years 1987-1989. This is a considerable increase over the prevalence in the preceding ten years. Twenty-six were classified as large tumours, 18 as medium and one was small. Surgical excision was complete in 16 and incomplete in 31 cases. Two patients died in the early postoperative period. Facial nerve function was preserved in 36 (80%) of cases; of these 27 (60%) had good function and nine (20%) fair function. Useful hearing was prevented in only two patients. The overall complication rate has been low and often of a transitory nature.

The role of diencephalic pathology in human memory disorder. Evidence from a penetrating paranasal brain injury.

A patient (B.J.) is reported who developed severe memory impairment following a penetrating brain injury caused by a snooker cue which entered through his left nostril into the basal regions of the brain. Initially, his memory disorder had the clinical features of a dense amnesic syndrome, with both anterograde and retrograde amnesia, but B.J. subsequently showed significant recovery of memory function. Formal memory testing was carried out 21 months after injury. This demonstrated marked verbal memory impairment, as severe as that seen in patients with the amnesic syndrome. On nonverbal memory tests, his impairment was relatively mild and patchy. His retrograde amnesia had regressed mainly to affect a 6 month period before the injury. On other cognitive tasks, he performed at an average or above average level, and there was no neuropsychological evidence of frontal lobe dysfunction. Neuroradiological investigations at various stages after his injury failed to demonstrate a lesion in any of the thalamic nuclei. Magnetic resonance imaging showed a lesion in the hypothalamus in the region of the mamillary bodies. Our study demonstrates that marked, relatively focal, memory disorder after diencephalic injury can occur without direct pathology to the body of the thalamus. It also indicates that structures in or adjacent to the hypothalamus, such as the mamillary bodies, may play a more important role in human memory functioning than has hitherto been considered.

Serpentine aneurysm of the posterior circulation: report of two cases.

Giant serpentine aneurysms form a subgroup of giant intracranial aneurysms with specific radiological and surgical features. Previous reports have stressed the predilection of these lesions for the carotid circulation, particularly the middle cerebral artery. Two cases of serpentine aneurysm affecting the posterior circulation are reported and the problems of diagnosis and treatment of this lesion are discussed.

Metastatic brain tumours in Northern Ireland: a retrospective review in a closed community with emphasis on short term quality of life.

One hundred and nineteen consecutive patients with metastatic brain tumours who presented to the Provincial Neurosurgical Service in Northern Ireland were studied. The detection rate doubled after computerised tomography became available though the population in Northern Ireland over the years of study stayed relatively stable. Multiple tumours accounted for 38% while solitary tumours occurred mainly in the cerebellum or parietal lobe. Whereas 70% of patients presented with features of increased intracranial pressure and or lateralizing neurological signs, 20% had only vague symptoms. The primary site was lungs in a third of cases but in 33 cases (27.5%), the site of origin remained unknown. 42% of those 76 cases operated were adenocarcinoma. More than 80% of these patients in whom excision of the tumours were done, had a better quality of life at one month compared with improvement in only a third after biopsy.