Controlled experiments of habitat fragmentation: a simple computer simulation and a test using small mammals.

Habitat fragmentation involves a reduction in the effective area available to a population and the imposition of hard patch edges. Studies seeking to measure effects of habitat fragmentation have compared populations in fragments of different size to estimate and area effect but few have examined the effect of converting open populations to closed ones (an effect of edges). To do so requires a shift in spatial scope-from comparison of individual fragments to that of fragmented versus unfragmented landscapes.

Endoscopic retrograde cholangiography in the diagnosis and endoscopic management of biliary complications after liver transplantation.

Objective: Biliary reconstruction in orthotopic liver transplantation is increasingly being performed without T tube drainage. This increases the difficulty of diagnosing subsequent biliary tract problems, with a greater reliance placed on endoscopic retrograde cholangiopancreatography (ERCP) for the diagnosis of biliary tract complications. The usefulness of ERCP was evaluated in patients who underwent liver transplant where biliary reconstruction was not done with T tube drainage.

Long-term prognosis of typical childhood absence epilepsy: remission or progression to juvenile myoclonic epilepsy.

Objective: To determine the proportion and characteristics of children presenting with childhood absence epilepsy (CAE) who were not taking anti-epileptic drugs (AEDs) and were seizure-free over the last year of long-term follow-up.

Methods: For case finding, centralized EEG records for the province of Nova Scotia allowed identification of all children with typical CAE diagnosed between 1977 and 1985. Follow-up was done in 1994 to 1995.

Use of transcutaneous pressure of oxygen in the evaluation of edematous wounds.

Transcutaneous pressure of oxygen (Ptco2) was measured in edematous wounds before and after a regimen of hyperbaric oxygen (HBO2) therapy, in patients breathing normobaric air (AIR), 100% normobaric oxygen (O2), and 100% O2 at 239 kPa (2.36 atm abs; HBO). Wounds also were scored for severity, including three ratings for periwound edema.

Accidental injury is a serious risk in children with typical absence epilepsy.

Objectives: To determine if young adults with a history of typical absence epilepsy (AE) in childhood have a greater risk of accidental injury than controls with juvenile rheumatoid arthritis (JRA). To assess the nature and severity of these injuries.

Methods: All patients with AE or JRA diagnosed between 1977 and 1985, who were 18 years or older at the onset of the study, were identified from review of pediatric electroencephalographic records for the province of Nova Scotia (AE) or review of the medical records database at the only tertiary care pediatric center for the province (JRA).

Organic osmolyte distribution and levels in the mammalian urinary bladder in diuresis and antidiuresis.

Inositol, sorbitol, glycerophosphocholine (GPC), and betaine are organic osmolytes that are accumulated by renal medullary cells in response to hyperosmotic stress. Previous screening studies, using nuclear magnetic resonance spectroscopy, have shown some of these same compounds to be present in extracts of whole urinary bladder from rabbits and rats. In the present study, we used high-performance liquid chromatography to quantify levels of these compounds in the separated epithelium and muscle of bladders taken from normal rabbits as well as diuretic and thirsted rats.

Families are content to discontinue antiepileptic drugs at different risks than their physicians.

Purpose: To define the risk of seizure recurrence (RSR) that families and physicians would accept before discontinuing antiepileptic drugs (AEDs) for children with controlled epilepsy.

Methods: A questionnaire was completed by families of 76 children with epilepsy > or = 3 months seizure-free and by their attending epilepsy specialist (n = 4).

Results: Forty-two percent of families were unwilling to discontinue AEDs with an RSR of 25%.

Will a critical level of hyperventilation-induced hypocapnia always induce an absence seizure?

We wished to determine if the degree of hypocapnia correlates with increased frequency of absence seizures and if there is a critical pCO2 at which absence seizures are reliably provoked. Twelve untreated children with newly diagnosed absence epilepsy were continuously monitored by EEG and end-expiratory CO2 recording during quiet respiration and hyperventilation (to absence seizure or exhaustion) while breathing four gas mixtures: (a) room air, (b) 100% O2, (c) 4% CO2 in room air, or (d) 4% CO2 + 96% O2). In quiet respiration, a reduction in number of spike and wave bursts and total seconds of spike and wave was noted in children breathing supplemental CO2 (gases c and d vs.

Transcutaneous oxygen measurements predict healing of leg wounds with hyperbaric therapy.

Twenty-six patients with chronic leg wounds had transcutaneous oxygen measurements taken from the peri-wound area and a chest reference site before undergoing hyperbaric oxygen therapy in order to evaluate the utility of transcutaneous oxygen measurements in predicting the response of wounds to hyperbaric therapy. Wound scores and wound areas were determined before treatment and after 10 hyperbaric exposures. Patients whose wounds averaged a 5% or greater reduction in wound score per treatment were designated "responders.

Discontinuation of anticonvulsant therapy in children free of seizures for 1 year: a prospective study.

We studied 97 children who were weaned from antiepileptic drug therapy 1 year after their last seizure. Medication was withdrawn over 4 to 8 weeks, and patients were followed for 12 to 57 months (32.4 +/- 13.

Failure of pulse intravenous methylprednisolone treatment in juvenile dermatomyositis.

Objective: To review the experience with high-dose intravenous pulse methylprednisolone (IVMP) therapy in patients with juvenile dermatomyositis (JDM) in our institution.

Study Design: We reviewed the charts of seven consecutive patients (four female subjects; three male subjects; age 3 to 18 years (mean age 8 years) treated for JDM between 1989 and 1992.

Results: All patients met the criteria of Bohan and Peter for JDM and were treated within 3 months of onset of weakness.

Use of space and habitats by meadow voles at the home range, patch and landscape scales.

Using capture/recapture methods, we examined the spatial usage patterns of Microtus pennsylvanicus within and between experimentally created habitat patches of three sizes (1.0, 0.25 and 0.

Experimental tests of nest site competition in two Peromyscus species.

The importance of interspecific competition for nest sites between the white-footed mouse (Peromyscus leucopus noveboracensis) and the cloudland deermouse (P. maniculatus nubiterrae) were investigated in the montane forests of southwestern Virginia over 3 years. Trials were conducted for both species using large, outdoor enclosures in order to examine: (i) nest site preference in isolation and (ii) nest site selection made in the presence of potential competitors.

Incidence of epilepsy in childhood and adolescence: a population-based study in Nova Scotia from 1977 to 1985.

Data from a regional EEG laboratory allowed us to identify almost all children in Nova Scotia (population 85,000) with one or more unprovoked, afebrile seizures from 1977 through 1985. We then reviewed hospital and pediatric neurology physician charts to limit cases to those with two or more definite afebrile seizures between the ages of 1 month and 16 years. In all, 693 children developed epilepsy: typical childhood absence seizures (AS) (97), either generalized tonic-clonic (GTCs) or partial seizures either secondarily generalized or not (511), and other generalized seizure types, including infantile spasms (IS) as well as myoclonic, akinetic, tonic, and atypical AS (85).

Does the number of seizures before treatment influence ease of control or remission of childhood epilepsy? Not if the number is 10 or less.

Using a population-based regional cohort of 479 children with epilepsy, we studied the effect of the number of pretreatment afebrile seizures on seizure control and remission. The number of pretreatment seizures varied from 1 to 20. For the first 10 pretreatment seizures, there was no significant difference or trend in (1) the proportion of children who were seizure free long enough to attempt stopping medication (mean, 70%), (2) the number of breakthrough seizures before control was achieved, or (3) the proportion of children who were seizure free after stopping medication for the first time (mean, 70%).

Lamotrigine-induced rash in children.

Of 68 children treated with lamotrigine, a new antiepileptic medication, five developed a rash. One child developed Stevens-Johnson syndrome on lamotrigine monotherapy. Of the five patients with the rash, three were admitted to the hospital (two to the intensive care unit).

EEG results are rarely the same if repeated within six months in childhood epilepsy.

Objective: To assess the reliability of interictal spike discharge in routine electroencephalography (EEG) testing in children.

Method: EEG results of all children diagnosed in Nova Scotia with epilepsy onset between 1977-85 (excluding myoclonic, akinetic-atonic and absence) were reviewed. The results of the EEG at time of diagnosis (EEG1) were compared with those of a second EEG (EEG2) within 6 months.

Benign rolandic epilepsy: atypical features are very common.

The objective of this study was to determine the frequency of atypical clinical and electrographic features in children with benign rolandic epilepsy. A retrospective case series design was employed in the setting of a tertiary care pediatric hospital. Forty-two children with benign rolandic epilepsy were seen through our neurology department between January 1, 1991, and December 31, 1993.

Magnetic field effects on spatial discrimination and melatonin levels in mice.

Previous research has demonstrated a decrement in spatial discrimination learning following exposure to a .30 Tesla magnetic field. It had been suggested that those findings might be the result of an interaction between the magnetic field and physiological ferromagnetic material (magnetite).