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Biomedical subjects

R Morris

Publications and source records attributed to R Morris.

At least 127 records · Page 7Linked to original sources
PubMed1998

Terson syndrome. Results of vitrectomy and the significance of vitreous hemorrhage in patients with subarachnoid hemorrhage.

OBJECTIVE: The purpose of study A was to assess the effectiveness of vitrectomy for Terson syndrome. The purpose of study B was to determine the incidence and significance of vitreous hemorrhage in patients with subarachnoid hemorrhage. DESIGN: Study A is a retrospective review of case series. Study B is a prospective study. PARTICIPANTS: Study A examined a consecutive series of 4 children (7 eyes) and 23 adults (26 eyes). Study B examined a consecutive series of 100 patients. INTERVENTION: Subjects in study A underwent pars plana vitrectomy for dense vitreous hemorrhage following intracranial hemorrhage. In study B, ophthalmoscopic examination of patients undergoing neurosurgery for ruptured cerebral aneurysms was used. MAIN OUTCOME MEASURES: In study A, the extent and rapidity of visual recovery and intraoperative and postoperative complications were examined. In study B, the incidences of intraocular hemorrhage and Terson syndrome in the cohort and the significance of the presence of vitreous hemorrhage in patients with subarachnoid hemorrhage were examined. RESULTS: Study A: There was substantial and rapid visual improvement in 25 of the 26 eyes (96%) of the adult patients, with 21 eyes (81%) achieving > or = 20/30 final visual acuity. Only limited improvement was achieved in children's eyes (< or = 20/60). Study B: Intraocular hemorrhage was found in 17% of eyes in patients with subarachnoid hemorrhage; the incidence of Terson syndrome was 8%. All patients with Terson syndrome and 89% of the patients with other types of intraocular hemorrhage had a history of coma compared with 46% of those without intraocular hemorrhage (P = 0.0003). CONCLUSIONS: Vitreous hemorrhage in patients surviving subarachnoid hemorrhage appears to be more common than previously thought, underscoring the need for routine funduscopic screening. Surgical intervention is highly effective in hastening visual rehabilitation of adults with Terson syndrome. The less encouraging results in infants may be due to amblyopia or direct brain damage caused by the cerebrovascular incident.

Adult↗
PubMed1998

Analysis of cocaine chronotoxicology in an urban ED.

To describe the chronotoxicology of cocaine and its potential impact on emergency department (ED) staffing and services, Drug Abuse Warning Network (DAWN) data from a single urban university ED were retrospectively reviewed. The DAWN data reviewed spanned an 11-year period (1/1/83 through 12/31/93), and 3,762 patients were enrolled. Patients were included if the ED records included documentation of recent cocaine abuse prior to presentation to the ED. Of the 3,762 study patients, 1,609 (43%) had documentation of recent cocaine use: 506 (32%) had used cocaine alone, 614 (38%) had used cocaine and ethanol in combination, and 489 (30%) had used cocaine in combination with other drugs. For all patients using cocaine, there were two significant rhythms (P < .05) identified: a circadian rhythm that peaked at 1800 and a 12-hour rhythm that peaked at approximately noon and midnight. A significant rhythmicity was found among cocaine-using patients who presented during the study period. Increased or shift-adjusted staffing focusing specifically on psychosocial services, detoxification, and security during these peak hours may provide more efficient emergent care for this subpopulation of patients.

Adolescent↗
PubMed1998

The responses of autistic children to the distress of others.

The behavior of preschool children from five groups (developmental language disordered, high-functioning autistic, low-functioning autistic, mentally retarded, and normally developing) were coded in three situations: presentation of a nonsocial orienting stimulus (an unfamiliar noise) and two social situations involving simulated distress on the part of an adult with whom they were playing. Cognitive level was correlated with level of responsiveness to stimuli only for the two retarded groups (mentally retarded and low-functioning autistic). Girls showed more prosocial behavior than boys in both social situations, independent of diagnosis. The language-disordered children showed only mild and subtle social deficits. The low-functioning autistic children showed pronounced deficits in responding in all situations. The mentally retarded and high-functioning autistic children showed good awareness of all situations, but were moderately impaired in their ability to respond prosocially; they rarely initiated prosocial behavior, but did respond to specific prompts. The behavioral feature that marked both autistic groups, in contrast to all other groups, was a lack of social referencing; they did not tend to look toward an adult in the presence of an ambiguous and unfamiliar stimulus. Results are discussed in terms of variability between and among high- and low-functioning autistic children, and implications for the core deficits in autism.

Affect↗
PubMed1998

Cost considerations with infertility therapy: outcome and cost comparison between health maintenance organization and preferred provider organization care based on physician and facility cost.

Of 98 retrospectively selected patient couples insured under one scheme (group I) who, based on performance of a hysterosalpingogram (HSG), were assumed to be under active infertility care, 96 were confirmed as infertile. These were matched by date, patient age and time of HSG to 96 patients under infertility care (group II). Both patient populations were then prospectively evaluated for outcome and cost of treatment. Total physician charges for groups I and II were similar. However, charges per achieved clinical pregnancy were higher in group I than group II since group I patients demonstrated a lower pregnancy rate (28/96, 29%) than group II patients (41/96, 43%) (P=0.05). Within group I, pregnancy rates were identical, whether treatment was provided by generalists or subspecialists. In group II, all care was provided by specialists. The number of days of treatment did not vary between groups I and H, though generalists in group I provided significantly fewer treatment days than specialists in either group I (P=0.003) or in group II (P=0.021). This was primarily due to a significantly higher patient drop-out rate in group I patients, and especially amongst those who received care from generalists (P < 0.0019). Group I patients also encountered significantly more surgical procedures than group H patients (P=0.0016). If physician charges are discounted and customary surgical facility costs are added, the actual cost structure for fertility care in group I patients was dramatically higher than in group II patients. The most cost-effective format to provide infertility care of high quality appears to be a managed care setting in which subspecialists provide a majority of care and in which patient choice is restricted to those subspecialists.

Female↗
PubMed1998

A comparison of the laryngeal mask airway and cuffed oropharyngeal airway in anesthetized adult patients.

UNLABELLED: We compared the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) in 120 anesthetized adult patients. We compared 1) placement success rates, 2) airway interventional requirements, 3) airway stability in different head/neck positions, 4) cardiorespiratory tolerance, and 5) intra- and postoperative adverse events/symptoms. A standardized anesthesia protocol was followed by four anesthesiologists experienced with both devices. Observational data were validated by independent analysis of continuous video recordings. Postoperative interviews were double-blind to the device used. The LMA had a more frequent success rate than COPA (97% vs 55%, P < 0.00001), an overall higher success rate (100% vs 83%; P = 0.001), a shorter time to achieve an effective airway (49 vs 188 s; P < 0.00001), a higher oropharyngeal leak pressure (21 vs 16 cm H2O; P = 0.003), and a fewer number of chin lift airway interventions required (0.1% vs 42%; P < 0.00001). When comparing mean tidal volumes in different head/neck positions to assess airway stability, the quality of airway was unchanged in 98% patients with the LMA and 54% with the COPA (P < 0.00001). The incidences of intraoperative adverse events were similar. On removal, blood was detected more often on the COPA (3% vs 14%; P = 0.04). In the late postoperative period, more patients complained of adverse symptoms with the COPA than with the LMA (26% vs 57%; P = 0.001). Late postoperative symptoms occurred more frequently with the COPA (0.87 vs 0.34; P = 0.003). There was more late postoperative sore throat (14% vs 36%; P = 0.0003) and more jaw/neck pain (12% vs 26%; P = 0.0008) in patients managed with the COPA. This study demonstrates that the LMA offers advantages over the COPA in most technical aspects of airway management and in terms of postoperative morbidity. IMPLICATIONS: In this randomized, prospective study, we compared the laryngeal mask airway and the cuffed oropharyngeal airway in anesthetized patients. The laryngeal mask airway offers advantages in most technical aspects of airway management and in terms of postoperative morbidity.

Adult↗
PubMed1998

A comparison of the disposable versus the reusable laryngeal mask airway in paralyzed adult patients.

UNLABELLED: A disposable (polyvinyl chloride) laryngeal mask airway (LMA) with dimensions identical to, but physical properties different from (stiffer tube/thicker cuff), the reusable (silicone) LMA has recently become available. We performed a randomized, cross-over study of 60 paralyzed, anesthetized patients to test the hypothesis that the use of these devices was different in terms of ease of insertion, airway sealing pressure, fiberoptic position, and changes in intracuff pressure during N2O anesthesia. We also tested the hypothesis that the airway sealing pressure of the LMA is suboptimal if the cuff is inflated to a high intracuff pressure. Both the devices were inserted into each patient in random order, and their performance was assessed at two intracuff pressures (60 and 180 cm H2O) by a blind observer. Subsequently, intracuff pressures were measured during N2O anesthesia for the second device. Ease of insertion was similar: there was no difference in first attempt success rates (97% vs 98%) and insertion times (15 vs 13 s) for the disposable and reusable LMA, respectively. There were no differences in airway sealing pressure or fiberoptic position. Airway sealing pressure was significantly higher at 60 cm H2O intracuff pressure compared with the airway sealing pressure at 180 cm H2O for both devices (P < 0.02). During N2O anesthesia, the intracuff pressure remained stable for the disposable LMA but increased significantly for the reusable LMA. We conclude that the disposable and reusable LMAs perform similarly in paralyzed adult patients, but that the disposable LMA has more stable intracuff pressures during N2O anesthesia. Inflation of the LMA to high intracuff pressures produces a suboptimal seal. IMPLICATIONS: This randomized, single-blind, within-patient study of 60 adult patients shows that the disposable (polyvinyl chloride) and reusable (silicone) laryngeal mask airways perform similarly, but that the disposable laryngeal mask airway has more stable intracuff pressures during N2O anesthesia. Inflation of either device to high intracuff pressures produces a suboptimal seal.

Adult↗
PubMed1998

Acute effects of oral glibenclamide on blood pressure and forearm vascular resistance in diabetics.

1. To determine the effects of an acute oral dose of glibenclamide on blood pressure (BP), basal forearm vascular resistance (FVR) and FVR responses to the K+(ATP) channel activating vasodilator diazoxide, a placebo-controlled, double-blind cross-over study was performed in eight male volunteers with non-insulin-dependent diabetes mellitus. 2. Changes in vascular responses to progressively increasing concentrations of diazoxide (3.75-30 mg/kg per min) and noradrenaline (25-100 ng/kg per min) were measured by venous occlusion plethysmography. 3. Glibenclamide significantly lowered plasma glucose levels compared with placebo (P < 0.02) and attenuated the decrease in FVR (P < 0.05) and the decrease in systolic BP (P < 0.05) that followed a meal. However, vasodilator responses to diazoxide were potentiated by the administration of oral glibenclamide (P < 0.01). 4. Acute administration of oral glibenclamide attenuates the normal decrease in FVR and systolic BP that follows a meal and potentiates rather than inhibits forearm vasodilator responses to intra-arterial diazoxide, probably via indirect humoral effects. These results suggest that glibenclamide has direct or indirect vasoconstrictor effects that antagonize the normal increase in forearm blood flow that follows a meal and that the inhibition of vascular K+(ATP) channels following acute oral glibenclamide administration is clinically insignificant compared with other indirect vascular effects of the drug.

Adult↗
PubMed1998

Topographic analysis of the gyral patterns of the central area.

Great advances in imaging technology allows the surgeon to visualize the entire brain surface during surgery. However, the cerebral convolutions are extremely complex, so that it is often difficult to define the central area precisely. Using the curvilinear reconstruction technique (Gyroview) and MRI, we have analyzed the gyral anatomy of the central area in 20 normal brans and have recognized several patterns of topographic organization and have classified them into several categories. We divided the central area into anterior and posterior subregions with the central sulcus as the main landmark. More specifically, we studied how the pre- and postcentral gyri merge into the frontal and parietal lobe proper by anatomical bridges (roots). We describe three anterior and two main posterior roots which originate from the precentral and the postcentral gyrus, respectively. We found four different types of pattern for the anterior roots and as many as 10 different patterns for the posterior roots. The arterior roots are relatively constant, compared to the posterior ones. The most frequent pattern (type 1) was found in 33 hemispheres among the 40 analyzed (82.5%). Four main posterior root patterns were recognized in 32 hemispheres of the 40 analyzed (80%). Thus, although gyral variability was encountered for the posterior roots, a very constant global pattern was seen for the central area. One of the most important steps of frameless stereotactic-guided epilepsy surgery is the precise localization of the central area. Therefore, a knowledge of gyral patterns of the central area is essential not only for the resective epilepsy surgery, but also for the successful removal of a variety of lesions in the central area.

Anatomy, Artistic↗
PubMed1998

Treatment of brain tumors in children is associated with abnormal MR spectroscopic ratios in brain tissue remote from the tumor site.

PURPOSE: Children who have brain tumors are at risk for a variety of treatment-related sequelae, including neuropsychological and cognitive impairment, neurologic deficits, and neuroendocrinologic disturbances. We sought to determine the value of proton MR spectroscopy in assessing brain tissue remote from the tumor site to ascertain the effects of chemotherapy and radiation treatment in these patients. METHODS: Single-voxel proton MR spectra from 70 patients (111 spectra) and 11 healthy volunteers (11 spectra) were analyzed. NAA/Cr, NAA/Cho, and Cho/Cr ratios based on peak areas were obtained from nonneoplastic regions of the frontal lobe. The relationship between MR spectroscopic ratios and treatment was determined. RESULTS: NAA-containing ratios were decreased in patients as compared with control subjects. The presence of gadolinium-based contrast material did not cause significant changes in the ratios as compared with precontrast data. When chemotherapy was a component of a child's treatment protocol, we found a significant decline in NAA/Cr ratios. Patients who underwent both chemotherapy and radiation therapy showed a trend toward lower NAA-containing ratios if the chemotherapy was administered before the radiation therapy. Patients receiving whole-brain radiation had a trend toward lower NAA-containing ratios than did those who had only focal tumor treatment. CONCLUSION: In children with brain tumors, MR spectroscopy of brain tissue remote from the tumor reveals treatment-related biochemical changes.

Adolescent↗
PubMed1998

[Low energy transcatheter atrial defibrillation in one patient with refractory atrial fibrillation].

Most cases of atrial fibrillation are converted with antiarrhythmic medications or external electric defibrillation. However, in some refractory patients, an internal transcatheter defibrillation must be attempted. We report a 50 years old male with an atrial fibrillation of one year duration that was refractory to pharmacological treatment and in whom external cardioversion was unsuccessful. After the application of a bifasic shock of 10 joules between a catheter in the right atrium and another one located at the coronary sinus, the patient was converted to sinus rhythm. At two months of follow up, the patient continues in sinus rhythm.

Atrial Fibrillation↗
PubMed1998

Heart transplantation in patients with heparin-induced thrombocytopenia on the Novacor left ventricular assist system.

We report on two patients with development of heparin-induced thrombocytopenia with thrombosis while on the Novacor left ventricular assist system. Heart transplantation was successfully performed in both patients with heparin used for cardiopulmonary bypass after careful monitoring of heparin-associated antibodies. The approach to the patients' management and potential alternatives for anticoagulation are discussed.

Anticoagulants↗
PubMed1998

[Implantable defibrillators in the management of malignant ventricular tachyarrhythmias. Experience at the Arrhythmia National Center].

BACKGROUND: Implantable defibrillators are the most effective means to prevent sudden death in patients with malignant ventricular tachyarrhythmias. The availability of this type of devices is limited in Chile, due to their high price. AIM: To report the first patients treated with implantable defibrillators in our hospital. PATIENTS AND METHODS: Nine males and one female aged 13 to 65 years old are reported. Three presented with ventricular fibrillation (presenting out of the hospital in three) and the rest had ventricular tachycardia resistant to drugs or radiofrequency ablation. RESULTS: All implants were performed using intracardiac electrodes. The generator was implanted in the pectoral region in nine and in the abdomen in one. A successful defibrillation was obtained with less than 15 J in four patients, with 20 J in three and with 24 J in three. There were no complications during the procedure. After a 12 months follow up, four patients have been treated by the implantable device. One of these subjects had a ventricular fibrillation in two occasions. One patient died of a bronchopneumonia two years after the implant. CONCLUSIONS: Implantable defibrillators are an effective therapy for the treatment of malignant ventricular arrhythmias with a high risk of sudden death.

Adolescent↗
PubMed1998

[Sudden death due to recuperated ventricular fibrillation: Brugada syndrome?].

We report a 47 years old male who was recuperated from a sudden death, and in whom the cardiological assessment showed a right bundle branch block and a fluctuating ST segment elevation V1 to V3. During the electrophysiological study, a polymorphic tachycardia and a ventricular fibrillation were induced. Procainamide administration enhanced ST segment alterations in right precordial leads, and isoproterenol normalized the EKG. All these disturbances are similar to the condition described by Brugada brothers. The patient was treated with an internal implantable defibrillator, without the use of antiarrhythmic drugs and is well after four months of follow up.

Bundle-Branch Block↗
PubMed1997

Identification of a neuronal endocytic pathway activated by an apolipoprotein E (apoE) receptor binding peptide.

Apolipoprotein E (apoE) is the only serum apolipoprotein that is also found in the extravascular fluid of the brain, where it is thought to play an important role in lipid transport in the central nervous system. In addition apoE has also been implicated in neural regenerative processes and in the etiology of Alzheimer's disease. Peptides derived from the receptor binding domain of apoE are biologically active and bind to low density lipoprotein (LDL) receptors and LDL receptor related protein. There is, however, no direct evidence that these apoE peptides are able to directly activate the endocytic process, either in the brain or elsewhere. In the present paper, we have used electron microscopy and video imaging fluorescence microscopy to investigate the effects of a peptide derived from the receptor binding domain of human apoE on endocytosis in cultured rat cortical neurons. We have found that this tandem dimer repeat peptide induces neuronal endocytosis via a receptor associated protein sensitive pathway. Although the peptide induces a rise in cytoplasmic calcium, this is not required for the induction of endocytosis. On the other hand, normal processing of the endocytic vesicles does appear to require the elevation of cytoplasmic calcium, since inhibition of the calcium response results in the accumulation of large endocytic vesicles.

Amino Acid Sequence↗
PubMed1997

Cyclic guanosine 3',5'-monophosphate-mediated neuroprotection by nitric oxide in dissociated cultures of rat dorsal root ganglion neurones.

In dissociated cultures of dorsal root ganglia (DRG) derived from 15-day-old rats, many neurones expressed nitric oxide synthase (NOS) and this expression was found to be reduced by nerve growth factor. The application of blockers of NOS caused selective death of those neurones expressing NOS. The soluble guanylate cyclase (sGC) blocker ODQ also caused neuronal death. The appearance of the neurones undergoing cell death was typical of apoptosis. This suggests that NO has a neuroprotective action in DRG neurones which is probably mediated by its activation of cyclic guanosine 3',5'-monophosphate. These observations are discussed in relation to the developmental and neuropathic changes in NOS expression by DRG neurones.

Animals↗
PubMed1997

Nerve growth factor inhibits the expression of nitric oxide synthase in neurones in dissociated cultures of rat dorsal root ganglia.

In dissociated cultures of DRG derived from 15-day-old rats the numbers of neurones expressing immunocytochemically detectable quantities of the neuronal isoform of nitric oxide synthase (nNOS) was determined and the effects of different culture media examined. The availability of NGF in the cultures was found to be a critical determinant of nNOS expression. In a serum-rich media (SRM) supplemented with NGF, 24% of the neurones expressed nNOS compared with 72% in the absence of added NGF and the presence of an antibody to NGF (t-test, P < 0.0001). Cultures grown in a defined media (DM) developed poorly and many neurones died, these cultures also showed poor growth of other cell types. Immunostaining for NGF revealed that some of the non-neuronal cells produce NGF and that this would be predicted to contribute to the survival of the neurones. In cultures in which neurones were dying most of the surviving neurones expressed nNOS suggesting it may have a survival promoting function.

Animals↗