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Biomedical subjects

M C Stevens

Publications and source records attributed to M C Stevens.

72 records · Page 4Linked to original sources
PubMed1988

Intracardiac thrombus and tricuspid valve obstruction: a complication of Hickman catheter use.

The risk of catheter-related sepsis is well recognized in immunocompromised patients with an indwelling central venous line, but the hazard of thrombus involving the right atrium is less well known. We report the case of a child who died after intraartrial thrombus obstructed the tricuspid valve. The predisposing factors and available treatment strategies are discussed.

Catheterization, Central Venous↗
PubMed1988

Urea kinetics in adults with homozygous sickle cell disease.

The kinetics of urea metabolism were measured in four adults with homozygous sickle cell disease (HbSS). On a dietary intake of 1.2 to 2.7 g protein/kg/d the rate of urea production was 188 to 277 mg nitrogen/kg/d. A relatively small proportion of the urea was excreted in the urine (40 per cent), with a high fixed rate of hydrolysis in the bowel, 145 mg nitrogen/kg/d. Although 50 per cent of the nitrogen from hydrolysed urea was resynthesized to urea, and a further 10 per cent may have been lost in the stool, it is estimated that 58 mg nitrogen/kg/d was available for synthetic metabolic activity. Urea kinetics in sickle cell disease subjects are markedly different from normals, and this may be a reflection of the metabolic demands for increased red cell synthesis.

Adult↗
PubMed1987

Early congenital syphilis and severe haematological disturbance.

The early clinical signs and symptoms of congenital syphilis are diverse but, if undiagnosed, signs of the disease may subside until the late stigmata appear. We report a case that illustrates that the haematological signs and symptoms may be so severe as to mimic a diagnosis of leukaemia or disseminated malignant disease.

Diagnosis, Differential↗
PubMed1986

Alpha thalassemia and the hematology of homozygous sickle cell disease in childhood.

alpha Thalassemia modifies the hematologic expression of homozygous sickle cell (SS) disease, resulting in increased total hemoglobin and HbA2 and decreased HbF, mean cell volume, reticulocytes, irreversibly sickled cells, and bilirubin levels. The age at which these changes develop in children with SS disease is unknown. Ascertainment of globin gene status in a large representative sample of children with SS disease has afforded an opportunity to study the hematologic indices in nine children homozygous for alpha thalassemia 2 (two-gene group), 90 children heterozygous for alpha thalassemia 2 (three-gene group), and 167 children with a normal alpha globin gene complement (four-gene group). The two-gene group had significantly lower mean cell volumes from birth, higher red cell counts from one month, lower reticulocytes from three months, and higher HbA2 levels from one year, as compared with the four-gene group. Children with three genes had intermediate indices but resembled more closely the four-gene group. Differences in total hemoglobin or in fetal hemoglobin between the groups were not apparent by eight years of age. The most characteristic differences of the two-gene group were the raised proportional HbA2 level and low mean cell volume, the latter having some predictive value for alpha thalassemia status at birth.

Age Factors↗
PubMed1986

Prepubertal growth and skeletal maturation in children with sickle cell disease.

In a longitudinal study of 298 children with homozygous sickle cell (SS) disease and 157 children with hemoglobin SC disease, between birth and 9 years of age, observations of weight and height were made. These were compared with similar data derived from an age- and sex-matched group of 231 children with a normal hemoglobin (AA) genotype. Growth in children with SC disease was not significantly different from that in normal children, but children with SS disease had statistically significant, and progressive, deficits in both weight and height before 2 years of age. The average deficit approached 1 SD below the normal mean for age by 9 years. Observations of skeletal maturity, based on radiologic assessment of bone age at the wrist, were made on a proportion of these children at 5 and 8 years of age. Children with SS disease were significantly retarded at 8 years but not 5 years, which is consistent with increasing deficit in height. These observations confirm the early impact of SS disease on physical development and provide standards from which clinical expectations of growth may be derived. The relevance of these findings and their relationship to the characteristic delay in pubertal development is discussed together with a review of possible etiologic factors. The benign nature of SC disease is endorsed by the absence of an effect on growth in the prepubertal child.

Age Determination by Skeleton↗
PubMed1985

Haematological change in sickle cell-haemoglobin C disease and in sickle cell-beta thalassaemia: a cohort study from birth.

The haematological changes in early years following neonatal diagnosis have been observed in representative groups of children with sickle cell-haemoglobin C (SC) disease, sickle cell-beta(+) thalassaemia, and in sickle cell-beta(0) thalassaemia. Most haematological indices in SC disease were intermediate between previously published values in SS disease and in AA controls, generally being closer to values in normal children. Exceptions were microcytosis which may be genetically determined and a striking elevation of mean cell haemoglobin concentration from age 2 months to 4 years. The combination of a raised MCHC and a lowered MCV is unusual and may be characteristic of SC disease. Features in sickle cell-beta thalassaemia generally differed according to the type of beta thalassaemia gene. Sickle cell-beta(0) thalassaemia had lower levels of haemoglobin, MCHC, red cell count, MCV, and higher reticulocytes, most differences being significant before 1 year. No differences between S beta(0) thalassaemia and S beta(+) thalassaemia were apparent in HbF levels (which resembled those in SS disease) or in HbA2 levels (which exceeded those in SS disease by 1 year of age).

Anemia, Sickle Cell↗
PubMed1983

Body shape in young children with homozygous sickle cell disease.

Body shape, defined by detailed anthropometric measurement, was compared in 64 children with homozygous sickle cell (SS) disease, and in 123 children with a normal hemoglobin (AA) genotype, aged 4 to 6 years. Children with homozygous sickle cell disease showed an average reduction in weight, height, sitting height, limb length, interacromial and intercristal diameters, and skinfold thickness. They showed increased anteroposterior chest diameters with an increased anteroposterior-lateral chest diameter ratio. This report establishes that the effect of homozygous sickle cell disease on growth patterns in childhood is apparent before the age of 6 years. The relationship to changes in body shape, seen during adolescence and in affected adults, and their possible determinants, are discussed.

Anemia, Sickle Cell↗
PubMed1982

Sickle cell-Hb Lepore Boston syndrome. Uncommon differential diagnosis to homozygous sickle cell disease.

Two siblings assumed on the basis of clinical and hematological evidence to have homozygous sickle cell (SS) disease were found to have a mother without sickle hemoglobin. Subsequent investigation and hemoglobin structural studies indicated the diagnosis to be sickle cell-Hb Lepore Boston syndrome. This syndrome generally manifests clinically significant sickle cell disease, and this genotype should be borne in mind in apparent SS disease where a parent without sickle hemoglobin in discovered.

Amino Acids↗
PubMed1981

Fetal hemoglobin and clinical severity of homozygous sickle cell disease in early childhood.

The relationship of the clinical features of homozygous sickle cell disease in the first two years of life to the level of fetal hemoglobin at age 6 months was investigated. Mean HgbF levels were significantly lower in children manifesting early palpable splenomegaly, dactylitis, acute splenic sequestration, and in those who died. The risks of dactylitis and ASS were significantly greater in patients with lower HgbF levels. Since early splenomegaly itself may increase the risks of ASS, infection, and death, the relationship of HgbF to these features was further analyzed within the early splenomegaly group. The results suggest that a low HgbF may have a direct effect on the etiology of ASS, but any effect on infection or death is probably mediated via its relationship with the appearance of a palpable spleen. A protective effect of a high HgbF on the risk of dactylitis was demonstrated coincident with the accepted theory of its pathogenesis. Early HgbF determinations may be of value in identifying patients at high risk of serious complications during infancy.

Anemia, Sickle Cell↗
PubMed1981

Acute splenic sequestration and hypersplenism in the first five years in homozygous sickle cell disease.

A cord blood screening programme initiated in June 1973 had screened 68 000 normal deliveries by February 1979 with the detection of 216 cases of homozygous sickle cell disease. Regular review of these children in the Medical Research Council paediatric clinic has identified acute splenic sequestration as a major cause of morbidity and mortality in the first 5 years of life. In addition to classical episodes characterised by peripheral circulatory failure, minor episodes of increasing anaemia associated with an enlarging spleen and an active marrow were also common. These minor episodes appeared to have predictive value in children who later developed severe life-threatening episodes of acute splenic sequestration. Sequestration. Sustained hypersplenism was also appreciably more common in children developing minor or major episodes of acute splenic sequestration compared with those without such a history. It is proposed that the classification of acute splenic sequestration be expanded to include these minor episodes, and that consideration be given to prevention of recurrences by splenectomy particularly in patients who also develop sustained hypersplenism.

Acute Disease↗
PubMed1981

Observations on the natural history of dactylitis in homozygous sickle cell disease.

The incidence of the hand-foot syndrome (dactylitis) has been studied in a group of 233 children with homozygous sickle cell (SS) disease followed prospectively from birth. Dactylitis affected 45% of the children by the age of 2 years, with most cases occurring before this age. Episodes were significantly more common during colder months of the year, similar to the seasonal relationship previously noted in painful crises. Comparison of hematologic indices at age 6 months in patients with and without development of dactylitis indicated a lower fetal hemoglobin and higher reticulocyte counts in affected patients. The occurrence of dactylitis in combination with low fetal hemoglobin may serve to identify high-risk patients with SS disease.

Anemia, Sickle Cell↗
PubMed1978

Fasting metabolism in infants. I. Effect of severe undernutrition on energy and protein utilization.

Fasting energy metabolism was studied in infants to determine the rates of utilization of endogenous carbohydrate, fat, and protein in relation to length of fasting, glucose homeostasis, other circulating energy substrates and hormones, and severe depletion of energy reserves due to prior malnutrition. Five subjects about 1 yr of age were each studied before and after restoration of their energy reserves. Following 3 days of a standard maintenance intake of energy and protein, the subjects were fasted until glycogen oxidation became negligible. Total energy utilization, determined by hourly oxygen consumption, did not diminish as a result of fasting but was significantly less when malnourished than when recovered, 66 versus 79 kcal/kg/day. In all cases the major energy source shifted from oxidation of dietary carbohydrate and glycogen to oxidation of fat, determined from the respiratory quotient, until the oxidation of glycogen became negligible and fat provided 94% of energy in the malnourished subjects after 21 hr and 92% in the recovered subjects after 27 hr. Utilization of protein, determined from urinary nitrogen excretion, remained very low in the malnourished infants accounting for a maximum of 4% of energy, 103 mg N/kg/day, whereas after recovery, protein utilization doubled as a result of fasting, finally accounting for 7% of energy, 226 mg N/kg/day (p less than 0.005). Urea accounted for 60% of total urinary N in both groups and plasma urea increased correspondingly in the recovered but not in the malnourished subjects. Plasma glucose decreased to about 40 mg/100 ml in both groups as glycogen oxidation diminished. The maximum amount of glucose that could have been derived from dietary carbohydrate, glycogen, glycerol, and amino acids decreased over this time from about 6 to 1 mg/kg/min. Alanine declined in relation to glucose concentration and was not different in the two groups in spite of the difference in urea production. Glycerol free fatty acids, beta-hydroxybutyrate, and acetoacetate increased in both groups, but the latter three of these remained significantly less in the malnourished group. Insulin decreased rapidly and remained equally low in both groups. Urinary epinephrine increased in both groups and cortisol was elevated after fasting, while growth hormone did not increase significantly. It is concluded that fasting infants complete the transition from dietary carbohydrate to endogenous fat as the major energy source much faster than do adults, proportionate to relatively greater energy utilization. Severe wasting did not prevent energy homeostasis in spite of greatly depleted body fat. Oxidation of fat continued to provide virtually all of the fasting energy requirements, although ketosis was relatively less. Utilization of endogenous protein also increased as a result of fasting but, by contrast, provided only a very small fraction of total energy, and this was substantially diminished as a result of wasting, similar to what has been found in starved adults...

Blood Glucose↗
PubMedDate not supplied

Pediatric oncology and hematology in Birmingham, England.

The hematology and oncology service at Birmingham Children's Hospital was established in the late 1960s and now is one of the largest in the United Kingdom. It provides comprehensive care for the entire range of childhood malignancies, coagulation disorders, and hemoglobinopathies and other hematological disorders, and undertakes bone marrow transplant and megatherapy/peripheral blood stem cell procedures. Research includes clinical trials of treatments of childhood cancers; molecular biology studies on leukemia, Hodgkin's disease, neuroblastoma, and sarconas; childhood cancer epidemiology, and geographical and racial incidence; and treatment of hemophilia and molecular investigation of coagulation disorders. These activities involve collaboration with local, national, and international research groups.

Child↗
PubMedDate not supplied

Spectrum of peritoneal mesothelioma in childhood: clinical and histopathologic features, including DNA cytometry.

Different types of peritoneal mesothelioma (PM) occur in children and adults. All these share certain histopathologic features but differ in other aspects, such as age of occurrence, site and sex predominance, etiology, and biologic behavior. The article describes four patients, two with cystic PM (one of whom had multiple recurrences) and two with malignant PM (one of whom had pleural metastases). These cases illustrate the variable behavior of this tumor in childhood and highlight the difficulties encountered in diagnosis and treatment. Three different groups of mesothelioma are recognized: a classic, asbestos-related, malignant mesothelioma of adults, typically occurring in the pleural cavity; a multicystic mesothelioma, predominantly affecting the pelvic peritoneum of young women and associated with a good prognosis; and mesotheliomas in children, which are not associated with asbestos exposure and have an unpredictable biologic behavior requiring individual treatment strategies. In the patients studied, DNA index measured by flow cytometry showed a difference between the cystic (aneuploid) and malignant (diploid) tumors. The proliferative rate (S phase) of the tumor was low in all four cases.

Adolescent↗
PubMedDate not supplied

Recurrent hemangiopericytoma of the chest wall: report of a case in a 5-year-old boy.

Hemangiopericytoma in infants and children is usually benign. A case of recurrent hemangiopericytoma of the mediastinum in a 5-year-old boy is reported. The tumor recurred twice because of incomplete excision in the first instance. Immunohistochemistry of this enigmatic tumor is reviewed and ultrastructural features are described. The importance of total initial excision of the tumor and a prolonged follow-up is highlighted.

Child, Preschool↗