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Biomedical subjects

F Kaufman

Publications and source records attributed to F Kaufman.

18 recordsLinked to original sources
PubMed2001

Risk factors for cerebral edema in children with diabetic ketoacidosis. The Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics.

BACKGROUND: Cerebral edema is an uncommon but devastating complication of diabetic ketoacidosis in children. Risk factors for this complication have not been clearly defined. METHODS: In this multicenter study, we identified 61 children who had been hospitalized for diabetic ketoacidosis within a 15-year period and in whom cerebral edema had developed. Two additional groups of children with diabetic ketoacidosis but without cerebral edema were also identified: 181 randomly selected children and 174 children matched to those in the cerebral-edema group with respect to age at presentation, onset of diabetes (established vs. newly diagnosed disease), initial serum glucose concentration, and initial venous pH. Using logistic regression we compared the three groups with respect to demographic characteristics and biochemical variables at presentation and compared the matched groups with respect to therapeutic interventions and changes in biochemical values during treatment. RESULTS: A comparison of the children in the cerebral-edema group with those in the random control group showed that cerebral edema was significantly associated with lower initial partial pressures of arterial carbon dioxide (relative risk of cerebral edema for each decrease of 7.8 mm Hg [representing 1 SD], 3.4; 95 percent confidence interval, 1.9 to 6.3; P<0.001) and higher initial serum urea nitrogen concentrations (relative risk of cerebral edema for each increase of 9 mg per deciliter [3.2 mmol per liter] [representing 1 SD], 1.7; 95 percent confidence interval, 1.2 to 2.5; P=0.003). A comparison of the children with cerebral edema with those in the matched control group also showed that cerebral edema was associated with lower partial pressures of arterial carbon dioxide and higher serum urea nitrogen concentrations. Of the therapeutic variables, only treatment with bicarbonate was associated with cerebral edema, after adjustment for other covariates (relative risk, 4.2; 95 percent confidence interval, 1.5 to 12.1; P=0.008). CONCLUSIONS: Children with diabetic ketoacidosis who have low partial pressures of arterial carbon dioxide and high serum urea nitrogen concentrations at presentation and who are treated with bicarbonate are at increased risk for cerebral edema.

Age Factors↗
PubMed2001

First-phase insulin release during the intravenous glucose tolerance test as a risk factor for type 1 diabetes.

OBJECTIVE: To determine the relationship between first-phase (1 minute + 3 minutes) insulin production during the intravenous glucose tolerance test (IV-GTT) and risk factors for developing type 1 diabetes. STUDY DESIGN: Relatives of persons with type 1 diabetes (n = 59,600) were screened for islet cell antibodies (ICAs). Subjects who had positive screening results underwent IV-GTT (> or =2 times), repeat ICA screening, insulin autoantibody (IAA) screening twice, and an oral glucose tolerance test. RESULTS: Of the 59,600 subjects in the study, 2199 (3.69%) had positive findings on initial ICA test. IV-GTTs were performed in 1622 subjects, with children <8 years having the lowest first-phase insulin release (FPIR) and subjects 8 to 20 years of age having the highest FPIR. The FPIR was lower for subjects with a confirmed positive ICA test result or a positive IAA test result, subjects with higher titers of ICA or IAA, and subjects who had an abnormal (impaired or diabetic) oral glucose tolerance test result. CONCLUSION: FPIR in the IV-GTT correlates strongly with risk factors for development of type 1 diabetes.

Adolescent↗
PubMed2000

The radiological approach to precocious puberty.

Precocious puberty is caused by a heterogeneous group of disorders, which range from idiopathic to malignant tumours. The radiologist's role is to help: (1) differentiate precocious puberty from pubertal variants; (2) identify the underlying cause of precocity if present; and (3) assess for effectiveness of treatment. This pictorial review discusses the types of precocious puberty and their underlying aetiologies, differentiates precocious puberty from pubertal variants and illustrates the appropriate imaging evaluation for the patient diagnosed with precocious puberty.

Algorithms↗
PubMed1999

HIV-associated immune dysfunction and delayed pubertal development in a cohort of young hemophiliacs. Hemophilia Growth and Development Study.

As part of the Hemophilia Growth and Development Study (HGDS), we investigated the relationship between HIV-associated immune dysfunction and delayed pubertal development in a cohort of 333 boys and adolescents with moderate or severe hemophilia who were between the ages of 6 and 19 years at study entry in 1989. Sixty-two percent of the cohort was infected with HIV in the late 1970s and early 1980s through exposure to contaminated clotting factor concentrates. The cohort was observed during follow-up at 6-month intervals; measurements taken at each follow-up visit included Tanner stage and CD4+ cell count. This analysis of data from the first 4 years of follow-up revealed statistically significant delays in pubertal development associated with increasing levels of immune dysfunction. Our results emphasize the importance of following pubertal development in HIV-infected adolescent boys since delays in maturation may reflect underlying disease progression.

Adolescent↗
PubMed1999

Association of collagen type 1 alpha1 gene polymorphism with bone density in early childhood.

Osteoporosis is a disease characterized by the development of nontraumatic fractures, most commonly in the vertebrae of elderly women. Approximately 500,000 elderly women in the United States are newly diagnosed with vertebral fractures every year, as the compressive strength of the vertebra, mainly determined by the density of cancellous bone and its cross-sectional area, declines with age. A recent study in women suggested that a polymorphism in the Sp1 binding site of the collagen type I gene (COLIA1) was related to decreased vertebral bone mass and vertebral fractures. Determining the phenotypic trait(s) responsible for this relationship and whether this association is manifested in childhood would further define the structural basis for decreased bone mass and help identify children "at risk" for fractures later in life. We therefore studied the COLIA1 gene polymorphism and measurements of the size and the density of vertebral bone in 109 healthy, prepubertal girls. On average, 22 girls with the Ss genotype and one girl with the ss genotype had 6.7% and 49.4% lower cancellous bone density in the vertebrae than girls with the SS genotype. In contrast, there was no association between the size of the vertebrae and the COLIA1 genotypes.

Aging↗
PubMed1999

Evaluation of the effects of oxandrolone on malnourished HIV-positive pediatric patients.

OBJECTIVE: To determine the safety and efficacy of anabolic therapy to prevent or reverse wasting and malnutrition in human immunodeficiency virus (HIV)-infected pediatric patients. The anabolic steroid, oxandrolone, was evaluated because of its safe and effective use in other pediatric conditions. METHODS: Nine HIV-positive children who were malnourished or at risk for malnutrition (4 females, 5 males; 4-14 years of age) took oxandrolone for 3 months (.1 mg/kg/day orally). Quantitative HIV ribonucleic acid polymerase chain reaction and CD4(+) T-cell levels, complete blood cell count (CBC) and chemistry profile, endocrinologic studies, resting energy expenditure, respiratory quotient, nutritional measures, body composition assessment with quantitative computed tomography, and skinfold body composition measurements were determined before treatment, during treatment (3 months), and for 3 months after treatment. Statistical analyses were completed using the Friedman two-way analysis of variance and Spearman correlation tests. RESULTS: No adverse clinical or laboratory events or changes in Tanner staging or virilization occurred. Quantitative HIV ribonucleic acid polymerase chain reaction and CD4(+) T-cell levels did not change significantly. Insulin-like growth factor 1 increased, suggesting an anabolic effect of treatment. The rate of weight gain increased during treatment and was maintained after treatment. Linear growth continued and was maintained throughout treatment, whereas bone age did not increase significantly. Anthropometric assessments indicated an increase in muscle mass and a decrease in fat while patients were on treatment, and a mild decrease of muscle and increased fat posttreatment. Likewise, computed tomography scan results demonstrated similar changes in muscle mass. Resting energy expenditure and respiratory quotient remained stable throughout treatment and follow-up. No significant changes were seen in the quality of life questionnaire. CONCLUSIONS: Treatment with oxandrolone for 3 months in HIV-infected children was well-tolerated, safe, and associated with markers of anabolism. The latter effect was maintained partially for 3 months after discontinuation of a 3-month course of therapy. Additional studies are needed to assess the potential benefits and risks of a longer course of therapy or a higher dose of oxandrolone in HIV-infected children.

Adolescent↗
PubMed1998

Differential effect of race on the axial and appendicular skeletons of children.

The prevalence of osteoporosis and the incidence of fractures are substantially lower in black than in white subjects, a finding generally attributed to racial differences in adult bone mass. Whether these racial differences are present in childhood is the subject of considerable interest, as the amount of bone gained during growth is a major determinant of future susceptibility to fractures. We measured the density and size of the vertebrae and femurs of 80 black and 80 white healthy children, 8-18 yr of age, matched for age, gender, height, weight, and stage of sexual development, using computed tomography. Race had a significant and differential effect on the bones in the axial and appendicular skeletons. In the axial skeleton, black children had greater cancellous bone density, but similar cross-sectional area of the vertebral bodies. In contrast, in the appendicular skeleton, black children had greater femoral cross-sectional area, but similar cortical bone area and cortical bone density. Compared to white children, vertebral bone density and femoral cross-sectional area at sexual maturity were, on the average, 10.75% and 5.7% higher, respectively, in black children. Such significant variations may contribute to the racial differences in the prevalence of osteoporosis between black and white adults.

Adolescent↗
PubMed1997

Differential effect of gender on the sizes of the bones in the axial and appendicular skeletons.

Recent observations suggest that throughout life the size of the vertebral bodies in females is smaller than that in males even after accounting for differences in body size. To confirm these reports and to determine whether similar differences exist in the appendicular skeleton, detailed measurements of the sizes of the vertebrae and the femur were obtained using computed tomography in 30 pairs of prepubertal boys and girls matched for age, height, and weight. Anthropometric parameters as well as gender influenced the cross-sectional area of the vertebrae. Heavier children had greater vertebral cross-sectional area than slender children regardless of gender, and the vertebral bodies were found to be significantly smaller in girls than in matched boys (approximately 11%), both using Student's t test (P < 0.0001) and its multivariate analog, the Hotelling's T2 test (P < 0.0001). In contrast to these findings in the axial skeleton, gender status did not influence the size of the bones in the appendicular skeleton, and neither the cross-sectional area (3.28 +/- 0.84 vs. 3.10 +/- 0.56 cm2) nor the cortical bone area (1.80 +/- 0.37 vs. 1.85 +/- 0.36 cm2) at the midshaft of the femur differed between boys and girls. These values, however, correlated strongly with all anthropometric indexes, and multiple regression analyses indicated that both measurements were primarily related to weight. The results suggest that although increases in mechanical loading associated with growth are the main determinant of the cross-sectional properties of the appendicular skeleton in children, factors other than body mass and related to gender have a significant role in the regulation of the sizes of the bones in the axial skeleton.

Body Weight↗
PubMed1996

Decreased cortical and increased cancellous bone in two children with primary hyperparathyroidism.

The basis for this study is two children with primary hyperparathyroidism (PHPT) who radiographically manifested both marked subperiosteal resorption and prominent osteosclerosis. We hypothesize that the parathyroid hormone (PTH) elevation not only increased osteoclastic resorption of cortical bone but also simultaneously enhanced cancellous bone formation, giving rise to osteosclerosis. In this report, we describe the changes in trabecular and cortical bone density, as measured by quantitative computed tomography (QCT), in these two young patients with severe PHPT, before and after removal of a parathyroid adenoma. Before surgery, the radiographic findings of subperiosteal resorption and osteosclerosis were associated with low cortical and high cancellous bone density values in both children. Within 1 week of surgery, both cortical and cancellous bone density values increased and serum concentrations of calcium and, to a lesser degree, phosphorus decreased due to the "hungry bone syndrome." Twelve weeks after parathyroidectomy, QCT bone density values and skeletal radiographs were normal in both patients. The findings suggest that in patients with severe PHPT, the catabolic effect of PTH on cortical bone may be associated with a simultaneous anabolic effect on cancellous bone, and PTH may cause a significant redistribution of bone mineral from cortical to cancellous bone.

Adenoma↗
PubMed1991

Vertebral bone density in insulin-dependent diabetic children.

To determine the effect of insulin-dependent diabetes mellitus (IDDM) on bone mass, we compared the trabecular and cortical bone density in lumbar vertebrae, measured by quantitative computed tomography (CT), in 48 white diabetic patients (23 females, 25 males; 5.2 to 19.6 years of age) with those of a control group of 48 healthy subjects, matched for race, sex, and age. Patients with neuropathy, retinopathy, nephropathy, and those with recent ketoacidosis were excluded from the study. The patient and control groups did not differ in sexual or skeletal maturation, weight, height, surface area, body mass index, abdominal fat, or paraspinal musculature. In diabetic children, cortical bone density was slightly but significantly lower than in controls (3.5% lower, P less than .02); there was no difference between patients and controls regarding trabecular bone density. The decrease in cortical bone density in the diabetic group did not correlate with age, sex, duration of diabetes, or glycosylated hemoglobin levels. These results suggest that in children with uncomplicated IDDM, decreased vertebral bone density is a minor abnormality that only affects cortical bone.

Adolescent↗
PubMed1990

Results after organ-preserving surgery for renal cell carcinoma. An Austrian multicenter study.

Data from 120 patients diagnosed as having renal cell carcinoma (RCC), and treated in an organ-preserving surgical manner were analyzed from 11 participating Austrian urological centers. The male to female ratio was 66:54. The subjects age ranged from 27 to 75 years with mean age of 59 years. The indication for conservative tissue-saving surgery was a solitary kidney in 48 instances, a bilateral RCC in 18 cases and, in 2 patients, a horseshoe kidney tumor. In 52 cases the indication for conservative surgery was a peripheral, easily resectable, low-stage tumor (elective indication). Results were comparable to radical nephrectomy of low-stage tumors especially relating to survival rates. Ninety-nine patients survived and were tumor free at the point of check up (December 1988). Thirteen patients had either local tumor recurrence and/or metastases and 5 patients died from the disease. The operative mortality and the morbidity rate was very low.

Adult↗
PubMed1982

[Control of recruitment of muscle motor units by optimization of energy expenditure].

In order to vary the force it is exerting a muscle calls upon a variable number of motor elements (spatial mobilisation) and modulates the contraction frequency of each of the fibers (temporal mobilisation). We have studied the frequency distribution as a function of the strength developed and of the elongation of the muscle, as well as the number of fibers recruited. Based on a double approach, experimental and mathematical, we propose a function controlling this two-fold muscular mobilisation: the optimisation of the energy expenditure. In other words, to develop a particular force, the number of fibers called upon and the contraction frequencies of each of them are such that the quantity of energy required by the muscle is a minimum. The study is limited to voluntary isometric muscular contraction. Using optimization techniques, numerical results corresponding to the model's simulation has been obtained by using a digital computer.

Energy Metabolism↗
PubMed1970

Biological electron transport systems.

The solid-state electrical conductivities of a number of ferredoxin model compounds are reported. For one of these compounds, (KFeS(2))(n), an electron transfer rate for a 25 A unit is shown to be at least 1 x 10(8) electrons sec(-1). The rate becomes proportionally larger for smaller molecular units. This rapid rate is consistant with a short pipe model for electron transport between two reaction sites. Some of the factors leading to this rapid transfer rate are considered.

Binding Sites↗
PubMedDate not supplied

Grandparent/caretaker education session.

The education session was well received. Including the session in the youth conference encouraged the whole extended family of the diabetic child to attend. The participants had fun learning together and sharing experiences in addition to learning the basics of how to care for the child with diabetes.

Aged↗
PubMedDate not supplied

Scleroderma-like changes in insulin-dependent diabetes mellitus: clinical and biochemical studies.

Children with insulin-dependent diabetes mellitus (IDDM) were examined for scleroderma-like changes of digital sclerosis and joint contractures. Of the 104 patients, 19 (18%) demonstrated these features; five patients had both multiple joint involvement and skin changes; three were studied in detail. All three had restrictive pulmonary disease. Histopathology of skin in these three patients demonstrated increased accumulation of collagen in the lower dermis. In two of the patients, the extractability of collagen in 0.5 N acetic acid was decreased by about 50% as compared with normal controls, which suggests increased cross-linkage of collagen. In addition, the mean nonenzymatic glycosylation of collagen in these three patients was 13 times that of controls. The results indicate that distinct histopathologic and biochemical changes can be detected in the skin of these patients. The results further support the hypothesis that nonenzymatic glycosylation may alter the turnover of collagen, thus contributing to the development of a scleroderma-like syndrome with skin, joint, and pulmonary findings in patients with IDDM.

Adolescent↗