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Biomedical subjects

H Lou

Publications and source records attributed to H Lou.

100 records · Page 6Linked to original sources
PubMed1984

Combined tetrahydrobiopterin-phenylalanine loading test in the detection of partially defective biopterin synthesis.

Deficiency in the synthesis of biopterin causes neonatal hyperphenylalaninemia. We report a 10-year-old girl of normal appearance with a partial defect in biopterin synthesis, normal intelligence and normal serum phenylalanine levels (95 mumol/l) (1.6 mg/dl). During her 1st year of life serum phenylalanine levels were 250 mumol/l (4 mg/dl) and phenylalanine loading performed at 6 months and 1 year of age was not followed by an increase in serum tyrosine. At 9 years of age she had developed a severely abnormal EEG with focal spike activity but no observable clinical abnormalities. Determination of urinary pterins showed abnormal low levels of biopterin and high levels of neopterin. Phenylalanine loading combined with oral administration of tetrahydrobiopterin (BH4) was followed by a normal increase in serum tyrosine and a normal decrease in serum phenylalanine. Considering the importance of BH4 for the synthesis of dopamine, catecholamines, and serotonin we suggest that these cases should be followed carefully. If neurological symptoms appear, e.g., epilepsy, it may be worthwhile to consider treatment with BH4 and neurotransmitter precursors.

Adolescent↗
PubMed1984

Perinatal brain ischaemia: impact at four years of age.

A group of 15 children for whom cerebral blood flow (CBF) had been determined during the first few hours of life were examined between the ages of 3 years 9 months and four years. Clinical neurological and psychological (Stanford-Binet) tests were carried out and in three cases a computerised tomographic examination was made. Poor articulation, dysphasia, attention deficits and low IQ were found significantly more often among the five children with a documented episode of ischaemia (CBF less than 20 ml/100g/min) in the neonatal period. By summarizing the number of abnormal findings, the difference between the groups was found to be highly significant. It is concluded that ischaemia during the first hours of life is a critical determinant for the development of congitive disorders.

Asphyxia Neonatorum↗
PubMed1984

The effect of hypocarbia on the cardiovascular system of puppies.

Respiratory alkalosis (hypocapnia) is used to treat persistent pulmonary hypertension in newborns. With the exception of the brain, there are no data on the effects of hypocapnia on organ blood flow in the neonate. Therefore, we examined the effects of 2 h of hypocapnia on blood pressure, oxygen consumption, cardiac output and organ blood flows in puppies. In six animals (group I), reducing the PaCO2 to 21.8 +/- 1.5 mm Hg (pH 7.62 +/- 0.04) caused an immediate and sustained reduction in cerebral blood flow (40%) and in myocardial blood flow (25%). There were no significant changes in arterial blood pressure, total body oxygen consumption, cardiac output, right and left ventricular rate-pressure product, or blood flow to the gut, liver, muscle, and kidneys. In four control animals (group II)(PaCO2 39.8 +/- 3.0, pH 7.38 +/- 0.04), there were no changes in any of the measured variables (arterial blood pressure, total body oxygen consumption, cardiac output, or blood flow to any organ, including brain and heart) during 2 h of normocarbic ventilation. We did not determine whether the reductions in cerebral and myocardial blood flows were detrimental. We suspect that they were not because the animals did not develop metabolic acidosis and they had normal cardiac outputs, and ventricular rate-pressure products throughout the study.

Acid-Base Equilibrium↗
PubMed1983

Arterial oxygenation determines autoregulation of cerebral blood flow in the fetal lamb.

We examined autoregulation of cerebral blood flow (CBF) over the range of oxygen tension commonly observed in the chronic fetal lamb preparation. Seventeen animals were surgically prepared under general anesthesia for chronic in utero studies. Based on measured resting arterial PO2 and calculated % saturation 24-48 h after surgery, two groups were defined: a normoxic group of eight with saturation of 57% or higher (our laboratory normal for physiologically stable preparations) and an hypoxic group of nine with saturation less than 57%. Regional CBF was measured with radiolabeled 15-microns microspheres. Autoregulation of CBF was assessed by measuring the change in CBF when fetal mean arterial blood pressure (MABP) was acutely decreased and increased by withdrawal and reinfusion of fetal blood. In normoxic animals CBF was constant over an MABP range of 42-61 torr in all four areas of the brain examined: cerebral hemispheres, basal ganglia, cerebellum, and brain stem. In hypoxic animals CBF was pressure dependent in all areas over an MABP range of 46-73 torr, i.e., autoregulation was abolished. These studies demonstrate that the mechanism of autoregulation is functionally developed in the mature fetal lamb, but operationally dependent upon arterial oxygen concentration. Below a saturation of approximately 50-60% CBF varies directly with perfusion pressure.

Animals↗
PubMedDate not supplied

New X-linked syndrome with apraxia, ataxia, and mental deficiency: clinical, cytogenetic and neuropsychological studies in two Danish families.

In 2 unrelated families 9 males presented with ataxia, apraxia, and neuropsychological abnormalities or mental deficiency, inherited as an X-linked recessive syndrome with partial clinical expression in obligate female carriers. The symptoms were present in early childhood and were non-progressive. Additional findings in 2 males were congenital "club-feet" and generalized seizures. The affected males were 13-62 years old at the time of our examination. Chromosome abnormalities including fragile X fra(X) could not be demonstrated in any case. Results of metabolic screenings were also normal. The clinical picture with X-linked recessive inheritance distinguishes this syndrome from previously described inherited hereditary ataxias.

Adolescent↗
PubMedDate not supplied

The handicap code of the ICIDH, adapted for children aged 6-7 years. Classification Group of the Nordic Neuropediatric Association.

The handicap section of the ICIDH was developed with the experience of adults in mind. In its original form the H Code is not immediately applicable to young children with disabilities. The Classification Group of the Nordic Neuropediatric Association has developed an adaptation of the H Code for use in children aged 6-7 years, and the adaptation is presented in this paper.

Activities of Daily Living↗