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Biomedical subjects

R Markowitz

Publications and source records attributed to R Markowitz.

At least 19 recordsLinked to original sources
PubMed2000

Direct measurement of LDL-C in children: performance of two surfactant-based methods in a general pediatric population.

OBJECTIVES: Several pediatric advisory groups have recommended selective screening for dyslipidemia in children. Low-density lipoprotein cholesterol (LDL-C) is measured clinically with the Friedewald calculation in fasting samples. Nonfasting measurement of LDL-C would be clinically useful in children. DESIGN AND METHODS: In the present study, we examine the performance of two surfactant-based direct LDL-C assays in paired samples, fasting and nonfasting, from 100 children. RESULTS: LDL-C in the fasting state was significantly lower with the Friedewald estimation: 2.43 +/- 0. 61 mmol/L, N-geneous (Genzyme Corp.) direct LDL-C: 2.30 +/- 0.59 mmol/L, and Roche (Roche Diagnostics) direct LDL-C: 2.32 +/- 0.57 mmol/L than with ultracentrifugation-dextran-sulfate-Mg(2+) precipitation (UC-DS): 2.47 +/- 0.64 mmol/L. Moreover, there was increased negative bias using nonfasting samples with N-geneous: 2. 25 +/- 0.56 mmol/L and Roche: 2.26 +/- 0.56 mmol/L compared with fasting UC-DS. Correlation with US-DS was highest for Friedewald (r = 0.974) and fasting N-geneous (r = 0.973), and lowest with nonfasting N-geneous (r = 0.849) and Roche in fasting (r = 0.891) and nonfasting samples (r = 0.747). The sensitivity at LDL-C concentration of 2.85 mmol/L for the two direct methods when either fasting or nonfasting samples were used, was lower than that obtained with Friedewald. CONCLUSION: Overall, these direct LDL-C assays demonstrated limited utility in screening children but may be useful in the management of lipid disorders.

Autoanalysis↗
PubMed1997

The 22q11.2 deletion: screening, diagnostic workup, and outcome of results; report on 181 patients.

A submicroscopic deletion of chromosome 22q11.2 has been identified in the majority of patients with the DiGeorge syndrome, velocardiofacial syndrome, conotruncal anomaly face syndrome, and in some patients with isolated conotruncal cardiac anomalies, Opitz G/BBB syndrome, and Cayler cardiofacial syndrome. We have evaluated 181 patients with this deletion. We describe our cohort of patients, how they presented, and what has been learned by having the same subspecialists evaluate all of the children. The results help define the extremely variable phenotype associated with this submicroscopic deletion and will assist clinicians in formulating a management plan based on these findings.

Abnormalities, Multiple↗
PubMed1990

Multicenter clinical trial of ibuprofen and acetaminophen in the treatment of postoperative dental pain.

Pharmacological management of pain for acute and chronic conditions has been guided by a scientific understanding of peripheral and central acting mechanisms for the control of inflammation as well as pain. Oral surgery pain is a reliable model to reference the effectiveness of commonly used analgesics such as ibuprofen and acetaminophen. A total of 706 patients who were experiencing moderate to severe pain received a single dose of ibuprofen, acetaminophen, or placebo. After 6 hours, the degree of pain relief and tolerance was assessed. Ibuprofen has important implications for postoperative pain in clinical practice.

Acetaminophen↗
PubMed1987

Iatrogenic causes of large pleural fluid collections in the premature infant: ultrasonic and radiographic findings.

Ten cases of large pleural collections, all of which were iatrogenically induced in premature infants, are presented. There were five instances of hypopharyngeal tears communicating with the right pleural space, three of chylothorax secondary to superior vena caval obstruction in patients undergoing total parenteral nutrition catheterization (TPN), and two of direct erosion by the inferior vena caval TPN catheter into the pleural space. Ultrasonography was most helpful in detecting these pleural collections. It is important to recognize the presence of pleural fluid in these infants as a marker of iatrogenic injury.

Catheterization↗
PubMed1987

Usefulness of chest radiographs in children with acute lower respiratory tract disease.

To determine how frequently and under what circumstances the chest radiograph changes pre-x-ray diagnoses and plans for management of suspected acute lower respiratory tract disease, experienced pediatricians performed a three-phased sequential evaluation (observation, history, physical examination), determined an initial diagnosis and the need for a chest radiograph after each phase, and recorded pre- and post-x-ray diagnoses and plans of management. Of the 102 children evaluated, the chest radiograph resulted in a change of the pre-x-ray diagnosis in 21% and pre-x-ray management plans in 16%. In the majority of these cases, a diagnosis previously considered less likely was "ruled in" or therapy was instituted rather than withheld. More important, when the pattern of decision making was consistent, with the initial diagnosis and the need for a chest radiograph remaining the same throughout all phases, the chest radiograph resulted in a change of pre-x-ray diagnosis in five (10%) of 48 patients, compared with a change in 16 (30%) of 54 when the pattern was inconsistent (P less than 0.02). Similarly, when the pattern was consistent, the pre-x-ray management was modified in only three (6%) of 48 patients versus 13 (24%) of 54 inconsistent cases (P less than 0.015). Chest radiographs are least useful when information from sequential observation, history, and physical examination is consistent in suggesting the same diagnosis and need for a chest radiograph. Radiographs appear to have greater impact on diagnosis and management when any inconsistencies arise.

Acute Disease↗
PubMed1987

CT-guided stereotaxic biopsy of brain tumors: new technology for an old problem.

On 63 patients, we used stereotaxic surgery combined with computer tomographic (CT) technology, for reasonably safe and precise biopsy of brain lesions. Histological confirmation was possible in 97% of the cases. More recently, we have also been using the CT-guided stereotaxic technique for brachytherapy, consisting of introduction of an array of radioactive isotope seeds (192Ir). The after-loading cannulas used for the isotope seeds are now also being used for introduction of probes for localized hyperthermia of brain tumors. CT-guided stereotaxic technique is proving to be a major technological advance both diagnostically and therapeutically.

Adolescent↗
PubMed1986

Maternal employment and use of pediatric clinic services.

This article explores the relative importance of maternal employment as a determinant of pediatric care utilization using data from a 6-month longitudinal study of pediatric clinic use. This study sample (N = 167) was taken from a population of users of a pediatric ambulatory care clinic of a large urban hospital. The clinic served an inner city with a predominantly low-income, working-class population. Independent variables come from personal interviews conducted with the mothers of the preschoolers and from a 4-week health diary. Data on episodic illness care use were obtained from the children's medical records. Results indicate that children of working mothers made fewer visits to the clinic than children of housewives. Somewhat different factors were associated with clinic use for children with employed mothers as compared with children with nonemployed mothers. Findings from multivariate analyses suggested that mother's employment influenced utilization through its relationship with social support and daily stress. Work outside of the home was associated with greater social support as well as greater daily stress. Both social support and stress predicted utilization. Implications of these findings for future research are discussed.

Adult↗
PubMed1985

Delayed gastric emptying in children with Crohn's disease.

To evaluate the role of delayed gastric emptying in the decreased nutritional intake and growth retardation of some patients with Crohn's disease, we looked at four groups: 1) Crohn's disease with growth retardation; 2) Crohn's disease with malnutrition or acute weight loss; 3) Crohn's disease without growth retardation or malnutrition; and 4) normal controls. Gastric emptying was measured by a test meal incorporating 99mTc sulfur colloid-labeled chicken liver as the solid phase marker and 111In-labeled water as the liquid phase marker. The percent of each isotope retained in the stomach over 120 minutes was compared among the groups and correlated with established nutritional parameters, caloric intake, and disease activity. Gastric emptying of the liquid component was the same in all groups, and emptying of solids in patients with Crohn's disease and growth retardation was not significantly different from controls. However, gastric emptying of solids was delayed in five of seven patients in the malnourished group; the mean emptying rate of all seven patients was significantly slower compared both to the normals (p less than 0.01) and the Crohn's patients without growth disturbances (p less than 0.05). This delay was correlated with caloric intake, but not with disease activity or any individual nutritional parameter except arm muscle area (p less than 0.01). Multiple regression analysis revealed that 54% of the variation in the emptying of solids could be accounted for by nutritional factors. Fifty-seven percent of patients with delayed gastric emptying had radiologic and/or endoscopic evidence of nonconstrictive involvement of the duodenum with Crohn's disease, while 80% of patients with such involvement had delayed gastric emptying. These results help explain the decreased caloric intake observed in Crohn's disease patients and support the role of liquid caloric supplements.

Adolescent↗
PubMed1982

Effect of intensive insulin treatment on linear growth in the young diabetic patient.

Although impaired growth is a well-recognized complication of uncontrolled diabetes, it has not been established whether less severe metabolic derangements commonly seen with conventional treatment adversely affected growth potential. To examine this question, growth velocity was measured in nine type 1 diabetic patients (age 14 +/- 3 years) before and after six months of intensive insulin treatment either with the insulin pump or with multiple injections, which lowered mean plasma glucose concentration from 270 +/- 96 to 105 +/- 55 mg/dl and total glycosylated hemoglobin from 12.4 +/- 3.0 to 8.4 +/- 1.5% (mean +/- SD). During conventional treatment, growth velocity (5.3 +/- 2.2 cm/year) was within the range of normal despite elevations in plasma glucose concentrations. However, growth velocity increased sharply during intensive treatment (to 9.4 +/- 3.9 cm/year, P less than 0.005), reaching values in excess of normal in seven patients. The increase in growth velocity observed during intensive treatment was associated with a twofold rise in plasma somatomedin-C values. Skeletal maturation, previously normal or slightly delayed, did not advance excessively. These data indicate that the metabolic changes accompanying intensive treatment may enhance growth in diabetic children, even in those with apparently normal growth velocity during conventional therapy.

Adolescent↗
PubMed1982

Evolution of an HMO.

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Blue Cross Blue Shield Insurance Plans↗
PubMed1977

Thrombosis of the left coronary artery in a newborn infant.

A unique occurrence of antenatal thrombosis of the left main coronary artery in a term infant is presented. The clinical features are indistinguishable from those of several other forms of congenital heart disease. The etiology of the thrombosis is unknown.

Autopsy↗
PubMed1976

Radiation injury to abdominal aorta and iliac artery sustained in infancy.

Late complications of radiation therapy will become more common as treatment of neoplasms in childhood becomes more successful. A patient with a successfully treated Wilm's tumour presented with hypertension 3 years after therapy. Angiography revealed extensive damage to the aorta and left common iliac artery, probably caused by the radiation therapy. The hypertension was the result of renal artery stenosis.

Aorta, Abdominal↗
PubMed1976

Naloxone blockade of morphine analgesia: a dose-effect study of duration and magnitude.

The purpose of the experiment was to determine the minimal dose of naloxone needed to block the analgesic effect of morphine as measured by the foot-shock titration procedure in the rat. Various groups of rats received, subcutaneously, various doses of naloxone hydrochloride, from 0.03 to 2.0 mg/kg, 15 minutes before receiving 10 mg/kg of morphine sulfate. The results indicate that 1.0 mg/kg of naloxone is the minimum dose necessary to provide full blockade of the measured morphine effect for up to 5 hours after the morphine administration. Partial blockade was evident at doses much smaller than 1.0 mg/kg of naloxone. A dose of 0.125 mg/kg of naloxone completely blocked the onset of a measurable effect from 10 mg/kg of morphine for 60 minutes in six out of the seven animals tested at that dose. The results provide a clear dose-effect relationship for both magnitude and duration of naloxone blockade of the analgesic effect of morphine.

Animals↗