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Biomedical subjects

L Lawson

Publications and source records attributed to L Lawson.

At least 37 records · Page 2Linked to original sources
PubMed1993

The effect of racial misclassification on estimates of end-stage renal disease among American Indians and Alaska Natives in the Pacific Northwest, 1988 through 1990.

Although several recent studies have documented a high incidence of end-stage renal disease (ESRD) among American Indians (AI) and Alaska Natives (AN), racial misclassification of AI/AN as members of other races on disease registries has not been accounted for. We conducted a study to link the Northwest Renal Network (NRN) ESRD database, which includes persons known to have begun dialysis in Idaho, Oregon, and Washington, and the Indian Health Service (IHS) patient registration file, which includes AI/AN enrolled for health care provided or paid for by IHS in the same states, for the period January 1, 1988 to December 31, 1990. Among the 3,356 persons included on the NRN ESRD database, 68 (2.0%) were coded as AI/AN. Of the 68 listed as AI/AN, 54 (79.4%) were identified on the IHS patient registration file. In addition to the 68 cases coded on the NRN as AI/AN, we identified 12 cases that were definitively matched to the IHS patient registration file but not coded AI/AN on the NRN. The age-adjusted annual incidence of ESRD treatment initiation among AI/AN in Idaho, Oregon, and Washington was 267.5 per million according to original racial coding on the NRN, but it increased to 311.6 per million after correction for racial misclassification. Among IHS-registered AI/AN, the annual incidence increased from 394.1 per million to 474.3 per million. Racial misclassification of AI/AN in ESRD registries may result in underestimates of AI/AN ESRD incidence for the United States.

Adolescent↗
PubMed1993

Serum albumin concentration-related Health Care Financing Administration quality assurance criterion is method-dependent: revision is necessary.

The objective of this study was to examine quantitative differences between the two commonly used methods for determining serum albumin concentration, bromcresol green (BCG) and bromcresol purple (BCP), in normal subjects and in 235 unselected dialysis patients in view of recently established Health Care Financing Administration (HCFA) quality assurance review criteria. The mean of normal results by the BCG method was 4.4 g/dL, and 97.5% of values were 3.8 g/dL or higher. The mean of normal results by the BCP method was 3.9 g/dL, and 97.5% of values were 3.3 g/dL or higher. Serum albumin concentrations in samples from the dialysis patients had respectively lower mean values by both methods. For the BCG method, the mean was 3.8 g/dL, and 82% of values were 3.5 g/dL or higher; for the BCP method, the mean was 3.3 g/dL, and 82% of values were 3.0 g/dL or higher. Likewise, for the reference immunonephelometric procedure, the mean value for the dialysis patients was 3.3 g/dL, and 82% of values were 3.0 g/dL or higher. For the samples from the dialysis patients, in comparison with the immunonephelometric method, the BCG method exhibited both constant (intercept = 9.3 g/L) and proportional error (slope = 0.87). The mean albumin value for the BCG method was 3.8 g/dL, 15% higher. In contrast, the BCP method compared closely with the reference method: slope = 1.00, intercept = 0.8 g/L, mean x = 3.3 g/dL, mean y = 3.3 g/dL. The HCFA quality assurance criteria are valid only for the BCG method.(ABSTRACT TRUNCATED AT 250 WORDS)

Bromcresol Green↗
PubMed1993

An unusual form of pulmonary aspergillosis in two patients with the acquired immunodeficiency syndrome.

Two cases of an unusual pathologic form of pulmonary aspergillosis in patients with the acquired immunodeficiency virus are reported. Each was characterized by chronic cavitary disease with involvement of small bronchioles and extension into subtending alveoli. It is suggested that this variant would best be described as chronic cavitary and invasive bronchopulmonary aspergillosis. A prominent feature in each case was the presence of numerous cytomegalovirus inclusions adjacent to the cavities and affected airways. The significance of this association is not known.

AIDS-Related Opportunistic Infections↗
PubMed1993

Predictors of self-reported psychopathology in children abused repeatedly by a parent.

OBJECTIVE: This study was designed to test the influence of gender, type of abuse, and other factors on the development of psychopathology in abused children. METHOD: Forty-one children who had been abused repeatedly either physically or sexually by a parent or parent figure were given the revised Diagnostic Interview for Children and Adolescents. RESULTS: Logistic regression analyses showed: conduct disorder was predicted by male gender and increasing age regardless of type of abuse; post-traumatic stress disorder was predicted by number of stressors other than abuse and not by sexual abuse versus physical abuse. Predictors of somatization, psychotic symptoms, suicidal ideation, and separation anxiety also were identified. CONCLUSIONS: Gender, age, and stressors other than abuse contribute to the prediction of psychiatric disorder in abused children. Early interventions with young abused boys could help prevent development of violent behavior or conduct disorder; case work to reduce other stressors and treatments designed to reduce the impact of stressors may ameliorate developing post-traumatic stress disorders and other emotional disorders in abused children.

Adolescent↗
PubMed1993

Identification of macrophages and dendritic cells in the osteopetrotic (op/op) mouse.

We used a panel of monoclonal antibodies and immunocytochemistry to identify macrophages and dendritic cells in mice that are deficient in macrophage colony stimulating factor (M-CSF or CSF-1) because of the recessive osteopetrotic (op/op) mutation. Prior work had shown that osteopetrosis is associated with a lack of osteoclasts, phagocytic cells required for remodelling in bone. Additional macrophage populations proved to be very M-CSF dependent. op/op mice had few and sometimes no peritoneal cavity phagocytes, splenic marginal zone metallophils, and lymph node subcapsular sinus macrophages. Other populations, however, reached substantial levels in the absence of M-CSF, including phagocytes in the thymic cortex, splenic red pulp, lymph node medulla, intestinal lamina propria, liver (Kupffer cells), lung (alveolar macrophages) and brain (microglia). Dendritic cells, which are specialized accessory cells for T-dependent immune responses and tolerance, were readily identified in skin and in the T-dependent regions of spleen, lymph node and Peyer's patch. The identification of dendritic cells utilized antibodies to MHC class II products and four different antigens that are primarily expressed by these accessory cells. Our findings indicate that only a few macrophage populations are critically dependent upon M-CSF in vivo. With respect to dendritic cells, the data are consistent with prior in vitro work where it was noted that GM-CSF but not M-CSF supported dendritic cell viability, function and growth.

Animals↗
PubMed1993

Modification of catalytic properties of chicken liver fructose 1,6-bisphosphatase by allicin.

The activity of chicken liver fructose 1,6-bisphosphatase increases dramatically after incubation with allicin, a major biologically active compound produced by garlic. Activation is more pronounced when the enzyme is assayed with Mn2+ than Mg2+. Maximum activation is accompanied by the disappearance of 4 highly reactive sulfhydryl groups per molecule of enzyme. This modification also leads to loss of activation by K+, and reduced sensitivity to inhibition by AMP, fructose 2,6-bisphosphate, and high concentration of fructose 1,6-bisphosphate. All the altered properties induced by allicin can be reversed by dithiothreitol or tris(2-carboxyethyl)phosphine, the latter being much more effective.

Animals↗
PubMed1993

A comparison of Epi-Lock and saline dressings in the treatment of pressure ulcers.

The use of Epi-Lock dressings was compared to moist saline dressings as a treatment for Stage II and III pressure ulcers in 38 patients. Demographic and clinical data were collected at the onset of the investigation. At the time of enrollment and during weeks six, 12 and 24, pressure ulcers were inspected and measured, and laboratory data were collected. More healing occurred with Epi-Lock dressing than with moist saline dressing for Stage II and III pressure ulcers. Although individual Epi-Lock dressings were more expensive than saline dressings, they required less dressing changes. Therefore considering cost of nursing time, Epi-Lock dressings are more cost effective.

Adult↗
PubMed1992

Spectrum of tuberculosis in patients with HIV infection in British Columbia: report of 40 cases.

OBJECTIVE: To review the clinical features, treatment and outcome of all known cases of tuberculosis in patients with human immunodeficiency virus (HIV) infection in British Columbia between 1984 and 1990. DESIGN: Retrospective case review. SETTING: Provincial tuberculosis registry and university-affiliated HIV clinic. PATIENTS: All people with HIV infection in whom active tuberculosis was diagnosed during the study period. RESULTS: All 40 patients identified were men; their mean age was 38 years. Of the subjects 30 (75%) were homosexual, 6 (15%) were homosexual and used intravenous drugs, 2 (5%) just used intravenous drugs, and 1 (2%) had had heterosexual contact with prostitutes; for the remaining subject the risk factor for HIV infection was not established. In all cases cultures of specimens from 15 body sources yielded Mycobacterium tuberculosis. Thirty-five of the patients had acquired immunodeficiency syndrome (AIDS), and five had HIV infection uncomplicated except for tuberculosis. In 28 (70%) of the cases no AIDS-defining disease had previously been diagnosed, and in 23 (58%) extrapulmonary tuberculosis represented the AIDS-defining disease. Symptoms at presentation included weight loss (in 80% of the cases), fever (in 75%), cough (in 70%) and night sweats (in 55%). The mean CD4 lymphocyte count was 0.2 x 10(9)/L (in 15 cases). Tuberculin skin test results were positive in 8 of 16 cases. The most striking radiologic finding was intrathoracic adenopathy. All except one of the 36 patients who received appropriate treatment responded favourably at first. Adverse reactions necessitating changes in treatment occurred in 12 (33%) of the cases. Relapse occurred after completion of therapy in two cases (one at 3 weeks and the other at 9 months after treatment was stopped). Tuberculosis was the cause of death in five cases. CONCLUSIONS: Tuberculosis in people with HIV infection commonly presents as extrapulmonary disease and precedes or coincides with other AIDS-defining opportunistic infections. In most cases tuberculosis is the AIDS-defining disease. Even though radiologic findings are often unusual physicians should suspect tuberculosis. A careful examination for evidence of disease at multiple sites should be done. The duration and choice of therapy must be adequate to avoid relapse.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Aerosol pentamidine-induced bronchoconstriction. Predictive factors and preventive therapy.

OBJECTIVE: To describe the frequency of aerosol pentamidine-induced bronchoconstriction, its relationship to non-specific airway responsiveness, and its response to preventive therapy using salbutamol, ipratropium bromide, or sodium cromoglycate. METHODS: Consecutive HIV-infected individuals starting prophylactic AP were eligible if they had not been previously treated with this agent. Simple spirometry was performed before and 10 min after a single 60-mg dose given through an ultrasonic nebulizer. Methacholine challenge was performed in all subjects 24 h to four days after the initial AP dose. Subjects with a change in FEV1 (delta FEV1) greater than or equal to 10 percent decrease after the initial AP dose were restudied on three separate occasions (greater than 24 hours apart) after premedication with two puffs of salbutamol (200 micrograms), ipratropium bromide (40 micrograms), or sodium cromoglycate (2 mg), in random order. RESULTS: Fifty-three subjects were studied. The median delta FEV1 after a single dose of AP was -7.0 percent (range: -47 percent, 1.8 percent). The delta FEV1 following AP was only partially predicted by the degree of nonspecific bronchial responsiveness as measured by a standard methacholine challenge. Age, current smoking, history of asthma, baseline FEV1, or a prior episode of PCP failed to predict the delta FEV1 following AP. Eighteen subjects (34 percent) had a delta FEV1 greater than or equal to 10 percent decrease (median: -17.0 percent). In these subjects, after premedication with salbutamol, ipratropium bromide, and sodium cromoglycate, the median delta FEV1 was 1.0, 0.8, and -9.6 percent, respectively. CONCLUSION: Aerosol pentamidine produced a decrease in FEV1 greater than or equal to 10 percent in 34 percent of subjects. This was not accurately predicted by the methacholine response. The bronchoconstriction induced by AP was effectively prevented by either salbutamol or ipratropium, whereas cromoglycate was only partially effective.

Adult↗
PubMed1990

Tumor necrosis factor mRNA localized to Paneth cells of normal murine intestinal epithelium by in situ hybridization.

Paneth cells in normal murine small intestine contain TNF mRNA that is readily detectable by in situ hybridization, unlike resident macrophages in lamina propria, which are negative. Northern blot analysis of whole tissue shows the presence of mRNA that has the same electrophoretic mobility as TNF mRNA from activated macrophages. A low level of TNF bioactivity, but no immunoreactivity, was detected in normal small intestine, and TNF production in resting Paneth cells appears to be post-transcriptionally controlled. Typical leukocyte surface membrane markers were not found on Paneth cells, but were expressed by the surrounding lamina propria macrophages. Paneth cells are thus epithelial cells with leukocyte-like secretory potential that may be important in intestinal physiology and pathology.

Animals↗
PubMed1990

Residents' attitudes toward the legal system and court testimony in child abuse.

Resident physicians' contacts with the legal system during management of abused children may influence their attitudes, which were evaluated in a pilot survey completed by 42 pediatric and medicine/pediatric residents. Although negative attitudes toward attorneys were common, almost all of the residents considered general and hearing-specific legal training to be a legitimate part of their residency program. They reported lower levels of stress of court testimony than expected by the authors. Most who had testified in court believed their testimony had been needed and helpful, but all who believed their testimony had been a waste of time were senior-level residents. Although most residents believed the laws and courts usually work for protecting children, only 8 of the 20 residents who had previously testified in court responded affirmatively, and none of the 10 senior residents who had previously testified held this belief. The disillusionment of senior-level residents appeared to affect attitudes toward patient care less than expected, in that 90% of those who planned to enter private practice indicated they would perform physical abuse evaluations and 70% planned to perform sexual abuse evaluations. Only one resident who did not expect to perform the evaluations gave as a reason the prospect of having to testify in court.

Arkansas↗
PubMed1990

Bench and ambulatory field evaluation of the A & D TM-2420 automated sphygmomanometer.

Adequate evaluation of automated sphygmomanometers, in terms of safety, accuracy, mechanical reliability, patient acceptability and ability to record ambulatory blood pressure is essential before these devices are used in clinical practice and in clinical trials. We have evaluated the accuracy and performance of the A & D TM-2420 automated sphygmomanometer, an auscultatory device designed for ambulatory blood pressure recording. Four devices were tested for accuracy by simultaneous comparison against two experienced observers using standard mercury column sphygmomanometers. Two of these devices developed faults that precluded complete evaluation. One of the remaining devices met and one failed to meet the somewhat liberal criteria for accuracy recommended by the American Association for the Advancement of Medical Instrumentation, the current standard for evaluation (mean difference of less than or equal to 5 mmHg and standard deviation of differences less than or equal to 8 mmHg). The mean differences (standard deviation of differences) between observers for simultaneous triplicate observations of systolic/diastolic pressure in 50 subjects, including 35 hypertensives, were 0.8 (3.0)/-0.6 (2.4) mmHg. In comparison, the differences between each device and each observer were: device 11, observer 1, -6.4 (5.4)/-6.3 (9.9); device 11, observer 2, -5.6 (4.7)/-7.0 (10.4); device 12, observer 1, -4.9 (5.2)/-4.0 (7.5); device 12, observer 2, -4.1 (4.9)/- -4.5 (7.7) mmHg. Ambulatory trials were carried out with a further 10 devices. Of these, seven developed faults requiring their return to the supplier. Numerous additional problems were encountered with microphones, cuffs, leads and connections, the processing unit, error algorithms and data-handling software. The device was not capable of making truly ambulatory recordings. We do not confirm the previously favourable, but limited, evaluation of this device. We stress the vital importance of subjecting a number of devices to benchtesting for accuracy, and the need to undertake extensive 'field' testing before any devices can be considered suitable for ambulatory recording. Exercise testing under laboratory conditions is not an adequate substitue for true ambulatory evaluation.

Algorithms↗
PubMed1989

Acute respiratory failure secondary to Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. A potential role for systemic corticosteroids.

Pneumocystis carinii pneumonia (PCP) remains the most frequent life-threatening complication of HIV infection. A retrospective study was undertaken in an attempt to establish the incidence of acute respiratory failure (ARF) in AIDS-related PCP, its mortality, and the impact of adjuvant systemic corticosteroids on its outcome. Of 127 AIDS-related PCP episodes diagnosed at St. Paul's Hospital between Jan 1, 1981, and March 31, 1987, 27 developed ARF (21 percent), and the 24 who consented to ICU admission for ventilatory support were reviewed. All were given IV pentamidine or trimethoprim-sulfamethoxazole or both sequentially. Overall mortality of ARF secondary to AIDS-related PCP was 50 percent. The use of adjuvant systemic corticosteroids was associated with a decreased mortality. Of the 18 patients treated with IV hydrocortisone (400 to 1,000 mg/day in divided doses for the duration of ARF followed by a tapering regimen over 10 to 15 days), seven (39 percent) died, while five of six (84 percent) treated without corticosteroids died (p = 0.05). Survivors received ventilation for 5 +/- 2 (mean +/- SD) days and all were discharged from hospital after 20 +/- 4 days. Survivors were also younger (34 +/- 8 vs 43 +/- 10 years, p = 0.034) and presented earlier (14 +/- 3 vs 34 +/- 7 days after onset of symptoms p = 0.017). Known AIDS, previous PCP episodes, and arterial blood gas values at the onset of ARF did not correlate with outcome. We conclude that ARF secondary to AIDS-related PCP merits aggressive management. In particular, younger patients presenting early after the onset of respiratory symptoms appear to have a better prognosis. The decreased mortality associated with the use of adjunctive corticosteroids supports the need for prospective controlled evaluation of this therapeutic modality.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Surgical management of spontaneous pneumothorax in patients with acquired immunodeficiency syndrome.

Spontaneous pneumothorax has been reported with increasing frequency in patients with acquired immunodeficiency syndrome and Pneumocystis carinii pneumonia. In the past year, we treated 4 patients with spontaneous pneumothorax. All of them were treated with closed tube thoracostomy, and 1 patient with bilateral apical cysts eventually required bilateral thoracotomies and pleurectomies. Only 1 patient had an uncomplicated hospital course. The remaining patients had prolonged air leaks, and 2 had synchronous pneumothoraces. Pneumothorax appears to be associated with P. carinii pneumonia. We recommend closed tube thoracostomy as the initial treatment in symptomatic patients. Pleurectomy for air leaks persisting longer than seven days can be safely performed in patients fit for thoractomy.

Acquired Immunodeficiency Syndrome↗