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Biomedical subjects

C B Watridge

Publications and source records attributed to C B Watridge.

13 recordsLinked to original sources
PubMed1995

Metastatic paraganglioma causing spinal cord compression.

SUMMARY OF BACKGROUND DATA: Paragangliomas are neoplasms that arise from the autonomic nervous system-associated paraganglia. Most often they are benign tumors. However, infrequently they have been reported to metastasize. Involvement of the spine is rare and usually is intradural at the level of the cauda equina. OBJECTIVES: The authors report two cases of metastatic paraganglioma to the spine, both of which resulted in myelopathy from extradural spinal cord compression. Also provided is a review of the literature. CONCLUSIONS: Paragangliomas rarely metastasize to the spine. Management of the two reported patients involved spinal cord decompression followed by spinal stabilization procedures. Long-term ambulatory status was maintained in both patients. Radiation therapy may be an important adjunctive treatment after surgical removal of these tumors.

Adult↗
PubMed1989

Phenytoin prodrug 3-phosphoryloxymethyl phenytoin (ACC-9653): pharmacokinetics in patients following intravenous and intramuscular administration.

A phenytoin prodrug, 3-phosphoryloxymethyl phenytoin (ACC-9653; 1), has been developed with more favorable physicochemical properties than phenytoin for parenteral administration. The purpose of this study was to evaluate the pharmacokinetic profile of 1 following iv and im administration in adult patients receiving chronic oral phenytoin monotherapy. Each patient (9 males, 1 female) received a single iv dose of undiluted 1 equivalent to their twice daily phenytoin dose (100-200 mg). An equivalent dose of im 1 was administered in the gluteus maximus muscle one week later. Serial blood samples were obtained after each dose. Phenytoin and 1 concentrations were measured using HPLC. Compartmental analysis using weighted nonlinear least squares, and noncompartmental pharmacokinetic analysis were performed on each patient's concentration-time data. Data following iv 1 in eight of ten patients were best described using a two-compartment model. Mean pharmacokinetic parameter estimates for iv 1 in these patients were central volume of distribution (Vdc) of 0.040 +/- 0.0084 L/kg and plasma disappearance half-life (t1/2 alpha) of 8.0 +/- 2.9 min ("conversion" t1/2). Overall mean clearance (CL) was 0.24 +/- 0.080 L/kg/h in the 10 patients. Mean pharmacokinetic parameter estimates for im 1 were a rate constant (ka) of 2.47 +/- 1.41 h-1 and an absolute bioavailability (F) of 100.5 +/- 20.3%. Mean observed tmax values for phenytoin were 0.57 +/- 0.26 and 1.46 +/- 0.76 h following iv and im 1, respectively. Model-independent estimates of clearance agreed well with the compartmental analyses. Steady-state predose phenytoin concentrations did not significantly vary from the comparable concentrations following iv 1 administration (p = 0.22).(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1989

Complications of intracranial pressure monitoring in trauma patients.

A retrospective review of 175 intracranial pressure (ICP) monitors placed in 140 trauma patients over a recent 3-year period showed a 10.3% infection rate. Factors that were related to the development of an ICP monitor-related infection included: 1) duration of monitoring; 2) requirement for serial monitors; and 3) concurrent infection at other sites. These findings are discussed in light of the related literature concerning ICP monitoring and recommendations made to decrease the incidence of infection-related complications.

Adult↗
PubMed1989

Anatomic evaluation of cisternal puncture.

Cisternal puncture, although less frequently used since the advent of computed tomography and magnetic resonance imaging, is an important tool in the neurodiagnostic armamentarium. An anatomic study of cisternal puncture was conducted on fresh cadavers by direct visualization and fluoroscopic guidance of cisternal puncture. Anatomic and radiographic analyses demonstrated a dramatic dynamic anatomy of the cisternal space during cisternal puncture and indicated that "tenting" of the dura mater over the needle occurs reliably during cisternal puncture. Lateral fluoroscopy may decrease the risk of cisternal puncture by allowing visualization of needle depth in the cisternal space.

Cerebrospinal Fluid Shunts↗
PubMed1989

Traumatic carotid artery dissection: diagnosis and treatment.

Early diagnosis and successful management of traumatic carotid artery dissections require a high index of clinical suspicion. The diagnostic study of choice is cerebral arteriography. In this paper, 24 cases of traumatic carotid artery dissection are described. Presenting signs and symptoms include Horner's syndrome, dysphasia, hemiparesis, obtundation, and monoparesis. Patients detected early with mild neurological deficits fared well with treatment, while those with profound neurological deficits and delayed diagnoses had poor outcomes. Aggressive nonsurgical treatment is advocated including anticoagulation therapy for prevention of progressive thrombosis and arterial occlusion and/or distal arterial embolization with resultant cerebral ischemia. Direct surgical thromboendarterectomy is considered to carry high morbidity and mortality rates.

Adolescent↗
PubMed1988

Phenytoin pharmacokinetics in critically ill trauma patients.

Preliminary data have suggested that phenytoin systemic clearance may increase during initial therapy in critically ill patients. The objectives for this study were to model the time-variant phenytoin clearance and evaluate concomitant changes in protein binding and urinary metabolite elimination. Phenytoin was given as an intravenous loading dose of 15 mg/kg followed by an initial maintenance dose of 6 mg/kg/day in 10 adult critically ill trauma patients. Phenytoin bound and unbound plasma concentrations were determined in 10 patients and urinary excretion of the metabolite p-hydroxyphenyl phenylhydantoin (p-HPPH) was measured in seven patients for 7 to 14 days. A Michaelis-Menten one-compartment model incorporating a time-variant maximal velocity (Vmax) was sufficient to describe the data and superior to a conventional time-invariant Michaelis-Menten model. Vmax for the time-variant model was defined as V'max + Vmax delta (1 - e(-kindt)). Vmax infinity is the value for Vmax when t is large. The median values (ranges) for the parameters were Km = 4.8 (2.6 to 20) mg/L, Vmax infinity = 1348 (372 to 4741) mg/day, and kind = 0.0115 (0.0045 to 0.132) hr-1. Phenytoin free fraction increased in a majority of patients during the study period, with a binding ratio inversely related to albumin. Measured urinary p-HPPH data were consistent with the proposed model. A loading and constant maintenance dose of phenytoin frequently yielded a substantial, clinically significant fall in plasma concentrations with a pattern of apparently increasing clearance that may be a consequence of changes in protein binding, induction of metabolism, or the influence of stress on hepatic metabolic capacity.

Adult↗
PubMed1986

Analysis of 76 civilian craniocerebral gunshot wounds.

A retrospective analysis of 76 civilian craniocerebral gunshot wounds treated over a 20-month period is presented. The authors report a 62% mortality rate and conclude that the admission Glasgow Coma Scale (GCS) score is a valuable prognosticator of outcome. Other important findings were: patients with a GCS score of 3 invariably died, with or without surgical intervention; and the presence of intracranial hematomas, ventricular injury, or bihemispheric wounding was associated with a poor outcome. Standardized methods of data reporting should be adopted in order to allow multicenter trials or comparisons that might lead to management practices that could improve results.

Adolescent↗
PubMed1985

Lateral atlantooccipital dislocation: case report.

A case of lateral atlantooccipital dislocation is presented, and its successful management is outlined, demonstrating the importance of the physical examination and the utilization of computed tomography. Open reduction and stabilization with direct visualization of the spinal axis is the preferred method of treatment.

Adult↗
PubMed1981

Nervous system metastasis from carcinoma of the lung: three unusual cases.

Carcinoma of the lung, fairly common in middle aged men, may be silent and have its first manifestation as a metastatic lesion. In 25% to 35% of such cases the metastases are to the nervous system. Management is dependent upon many factors but satisfactory results can be obtained with proper screening. Three cases of nervous system metastases are presented-one occurred in an unusual site; one had an unusual clinical syndrome and one had prolonged latency.

Adenocarcinoma↗
PubMed1979

The surgical management of extracranial and intracranial occlusive disease.

The role of surgery in preventing transient ischemic attacks and stroke in certain occlusive vascular lesions is well-established. This is well-established when carotid endarterectomy for carotid stenosis with transient ischemic attacks is used. The overall surgical results are best achieved by the frequent performance of the procedure and meticulous attention to technical as well as medical features of this group of patients at risk. Continuing medical care of these patients is essential. The long-term mortality rate is augmented by the high incidence of myocardial infarctions. Complete cardiac evaluation and good medical care, at the time the patient is initially treated, should subsequently minimize this event. Although the microvascular bypass procedures are technically feasible and associated with a low mortality rate, their exact role in the medical management of patients with intracranial occlusive lesions is unproven. However, the procedure offers great promise and an exciting future for neurosurgery in stroke therapy.

Arterial Occlusive Diseases↗