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Biomedical subjects

L Lawrence

Publications and source records attributed to L Lawrence.

At least 55 records · Page 3Linked to original sources
PubMed1988

Fatal disseminated cryptococcosis following intraocular involvement.

A 33-year-old man was treated with systemic steroids for a retinal inflammatory lesion before the diagnosis of cryptococcal retinitis and meningitis was suspected. He died from central nervous system disease despite treatment with parenteral antifungals. Histopathological studies demonstrated ocular and disseminated systemic infection with Cryptococcus neoformans. Direct cryptococcal involvement of the eye is rare and is usually associated with disseminated disease. Systemic steroids must be used with caution, and patients who take these drugs require frequent monitoring.

Adult↗
PubMed1986

Molecular epidemiology of cytomegalovirus in a nursery: lack of evidence for nosocomial transmission.

During a 3-year period, cytomegalovirus (CMV) was recovered from the urine of 35 hospitalized newborn infants (15 with congenital and 20 with acquired infections). Two of the infants with acquired infections lacked maternal antibody to CMV (seronegative) and received transfusions from multiple seropositive blood donors. After seronegative blood products were used exclusively for seronegative low birth weight (less than 1300 gm) infants, none of 154 seronegative infants acquired CMV. CMV was recovered from one seronegative nurse who became infected during the study period. EcoRl digestion of the DNA of the nurse's isolate and of 34 of the 35 infant isolates revealed that no two were identical. LBW seropositive infants were randomized to receive either seronegative blood products or blood products from random donors; there was no significant difference in the number of acquired CMV infections. There were no deaths among 18 infants with acquired CMV infection. Hepatosplenomegaly and worsening bronchopulmonary dysplasia developed in one LBW infant. These results prove that nosocomial transmission of CMV did not occur frequently during the 3-year period.

Antibodies, Viral↗
PubMed1984

Disposition of [14C]aztreonam in rats, dogs, and monkeys.

[14C]aztreonam was administered as single 25-mg/kg doses to dogs (intravenously and subcutaneously) and monkeys (intramuscularly and intravenously) and as single 50-mg/kg doses (intramuscularly and intravenously) to rats. In rats and dogs, radioactive moieties were excreted primarily in urine; in monkeys, they were excreted about equally in urine and feces. Unchanged aztreonam accounted for 77 to 86% of the radioactivity excreted in the urine of rats, dogs, and monkeys; SQ 26,992, the metabolite resulting from hydrolysis of the monobactam ring, accounted for 10 to 15%; and minor, unidentified metabolites accounted for the remainder. In rats with cannulated bile ducts, about 15% of an intramuscular dose was excreted in bile in 24 h; the bile contained a greater percentage of metabolites than that found in urine. In dogs, the apparent elimination half-life of aztreonam in serum was 0.7 h after intravenous administration. Aztreonam and SQ 26,992 accounted for most of the radioactivity in the sera of dogs and monkeys. Serum protein binding of aztreonam and its metabolites ranged from 28 to 35% in dogs and from 49 to 59% in monkeys. In the three species studied, aztreonam was most extensively metabolized in monkeys; SQ 26,992 and other minor metabolites from monkey urine were tested and found to be devoid of any significant antimicrobial activity.

Animals↗
PubMed1979

Quality of life after stroke: a three-year follow-up.

Forty-five people who had suffered a stroke three years previously were interviewed, as were their close relatives and friends. Changes in their lives which they attributed to stroke were explored, and information was gathered about health and social care resources they had used or needed. It was evident that stroke had devastated many peoples' lives: they ceased work prematurely, their interpersonal relations had deteriorated and over 70% viewed their future with uncertainty or gloom. Physical disability in itself was less important than peoples' response to their disability; inappropriate and dysfunctional responses were present in over half. In spite of adequate medical care, 40% of subjects would have been assisted by social work assessment, counseling and direction to appropriate community services.

Activities of Daily Living↗
PubMed1979

Inhibition by ascorbic acid (vitamin C) of chemical detection of blood in urine.

Review of results of 9,620 consecutive urinalyses revealed 892 urines that contained microscopic evidence of erythrocytes and 98 for which there were discrepancies between microscopic evidence of hematuria (greater than 20 erythrocytes/high-power field) and chemical detection of blood (0 or "1+" when results should be "3+"). Eleven specimens (from ten patients) showed negative results of chemical tests for blood and greater than 40 erythrocytes/high-power field (HPF). Nine of these patients were receiving ascorbic acid supplementation. In a random sample of 20 patients with greater than 40 erythrocytes/HPF and strongly positive tests for blood, none was receiving ascorbic acid, a significant difference by chi-square analysis. In a prospective study, low levels of ascorbic acid inhibited chemical detection of blood. At 25 mg/dl ascorbic acid, 10--20 erythrocytes/HPF could not be detected; at 35 mg/dl ascorbic acid, greater than 20 erythrocytes/HPF were undetectable. For quantitation of the low level at which ascorbic acid inhibits chemical detection of blood, fresh urine specimens should be analyzed. Ascorbic acid is oxidated in vitro to products that partially inhibit detection of blood yet do not assay as ascorbic acid.

Ascorbic Acid↗
PubMedDate not supplied

Spastic paraplegia with iron deposits in the basal ganglia: a new X-linked mental retardation syndrome.

We report on a family with X-linked mental retardation (XLMR) and severe spastic paraplegia. Appearance is normal but there is severe involvement of the lower limbs (affected relatives never walked), with minimal involvement of the upper limbs and unusual MRI findings including macrogyria, white matter hypoplasia, lack of myelination and a markedly increased paramagnetic signal suggestive of iron deposition. Linkage studies documented possible linkage, with no recombination, between the disease locus and DXS424. A 7-point linkage analysis yielded a maximum LOD score of 1.9, (theta = 0.00) for three loci spanning Xq22-q25. The combination of the unusual clinical and MRI findings and the tentative localization to a region different than other XLMR syndromes with spastic paraplegia, provide good evidence that this is a new XLMR syndrome.

Adult↗
PubMedDate not supplied

Allan-Herndon-Dudley syndrome: clinical and linkage studies on a second family.

We restudied a family with X-linked mental retardation (XLMR) originally reported in abstract form by Davis et al. [1981]. All 8 living affected males were examined. Characteristics included severe mental retardation, spastic paraplegia, dysarthria, muscle wasting, scoliosis, broad shallow pectus excavatum, long face, large ears with minor modeling anomalies, foot deformities, joint contractures, and neck drop. Stature, OFC, testicular volume, high resolution chromosome and fragile X studies, and plasma amino acids were all normal. Their manifestations closely resemble those of a large family with XLMR originally reported by Allan et al. [1944] and restudied by Stevenson et al. [1990]. This condition has been termed the Allan-Herndon-Dudley syndrome (AHDS). As AHDS has been mapped to Xq21, mapping studies were undertaken to determine if this family maps to the same location. These studies demonstrate tight linkage to Xq21, with a maximum lod score of 2.88 obtained with probe pX65H7 (DXS72). Multipoint analysis located the mutant gene quite close to pX65H7 (multipoint Z = 4.14), slightly more proximal in Xq21 than was suggested by the data from the original AHDS family. It appears likely that this family is the second reported family with AHDS.

Adult↗
PubMedDate not supplied

Distinct patterns of microvascular endothelial cell morphology are determined by extracellular matrix composition.

Endothelial interactions with the extracellular matrix (ECM) play important roles in angiogenesis but whether specific ECM signals can determine specific cellular morphologies is unclear. The authors compared in vitro ECM-induced morphological responses of the phenotypically distinct human placental microvascular endothelial cells (HPMECs) with large vessel endothelial cells (HUVECs). HPMECs showed distinct patterns of reorganization in response to collagen-I or collagen-IV (monolayer disruption, sprouting, migration) and Matrigel or laminin-A (intussusception, cord formation, tubulogenesis), and an intermediate response to fibrin; whereas HUVECs responded similarly to collagen-1 and Matrigel (elongation, lattice formation, vacuolation) and showed little response to fibrin. Although the extent of collagen and Matrigel responses of HPMECs were increased by serum, acidic or basic fibroblast growth factor (aFGF, bFGF), or vascular endothelial growth factor (VEGF), and varied with matrix protein concentration, the basic patterns were matrix specific, and were independent of fibronectin. The collagen responses correlated with disruption of adherens and tight junctions and the formation of filopodial protrusions. Matrigel responses were associated with up-regulated junctional localization of VE-cadherin, and tubulogenesis developed mainly through paracellular remodeling rather than intracellular vacuolation. Overall, these findings suggest that distinct ECM interactions stimulate specific morphological responses. These signals may regulate morphological behaviour in the angiogenesis cycle, switching endothelial cells between migratory and vasculogenic phenotypes.

Antigens, CD↗
PubMedDate not supplied

Cytomegalovirus infections in neonates acquired by blood transfusions.

One hundred seventy-eight newborns were cultured for cytomegalovirus (CMV) on admission and weekly after 4 weeks of age until discharge. Eight (all with birth weights of 1050 g or less) acquired CMV while hospitalized. At least seven of the infected infants were born to CMV-seronegative mothers. The risk for seronegative infants weighing less than 1250 g of acquiring CMV was 24%. There was no correlation between duration of hospitalization and birth weight for infants hospitalized over 30 days. There was a significant correlation (P less than 0.0001) between the number of blood donors for an infant and the acquisition of CMV. Infected infants received blood from eight or more donors prior to CMV shedding. Infected low birth weight infants received blood from an average of 6.5 CMV antibody-positive donors, while uninfected low birth weight infants received blood from an average of 3.1 CMV antibody-positive donors. No infant received nonmaternal breast milk. After acquiring CMV, three infants died (only one was autopsied and had proved disseminated CMV disease), two developed hepatitis and one developed hepatosplenomegaly. These results suggest that acquired CMV infection is a significant risk to seronegative low birth weight infants who receive blood from seropositive blood donors.

Antibodies, Viral↗
PubMedDate not supplied

School-based care: clinical challenges and research opportunities.

PURPOSE: To explore clinical challenges and research opportunities in one school-based clinic in a faculty practice model of health care delivery CLIENT POPULATION: Ninth-through twelfth-graders at an Eastern urban high school, 80% of the students are from ethnic minorities CONCLUSIONS: Clinical, administrative, and research challenges need to be addressed on a larger scale through practice-based research networks across the country in order to have an impact on policy PRACTICE IMPLICATIONS: School-based care required integration of primary care and management of psychosocial and developmental needs. Practice in this setting includes primary, secondary, and tertiary prevention as intervention.

Adolescent↗
PubMedDate not supplied

The use of magnetic resonance imaging in the evaluation of retinoblastoma.

We examined a 4-year-old boy who had a painful blind eye, rubeosis iridis, and leukokoria. Ultrasonography and computed tomography (CT) detected intraocular calcification and other features suggestive of retinoblastoma. The CT scan showed extraocular extension along the optic nerve. Intracranial extension of the tumor could not be definitely excluded by CT scan with intrathecal metrizamide infusion. Magnetic resonance imaging (MRI) and CT performed after radiation and chemotherapy were useful in excluding intracranial spread of malignant cells, thereby aiding the selection of a surgical approach to ensure complete removal of the involved portion of the optic nerve.

Child, Preschool↗
PubMedDate not supplied

A study of the quality of prescriptions issued in a busy pediatric emergency room.

An analysis of 2,213 prescriptions written by physicians in a busy, urban pediatric emergency room revealed that only 110 or 5 percent had no errors or omissions of specifications. The quality of the prescriptions was evaluated according to the standards of acceptable prescribing for the following specifications: quantity, dosage, time interval between doses or specific hours to be given, and specific instructions. The hospital pharmacists, also under pressure, generally failed to monitor the prescriptions adequately--either they did not rectify the physicians' errors or at times they made incorrect changes. To improve the quality of prescriptions issued under pressure in an emergency room, several courses of action are recommended: Pharmacology departments of medical schools should place more emphasis on teaching students the art of writing explicit, comprehensible prescriptions. The physician and pharmacist should work as a team in the interest of providing patients with accurate and detailed prescriptions; or both the physician and the pharmacist should delegate the composition of prescriptions to an automated computer system, thereby reducing human error in writing and monitoring prescriptions and allowing both professionals more time for direct contact with patients.

Child↗