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Biomedical subjects

J Bjure

Publications and source records attributed to J Bjure.

At least 19 recordsLinked to original sources

Radiopharmaceutical dosage of 99Tcm-HMPAO for cerebral blood flow SPET studies in children.

Four methods of calculating the activity of 99Tcm-hexamethylpropyleneamine oxime to be administered in cerebral blood flow investigations of children were evaluated in patient studies. Three of the methods were based on the size of the child. We also constructed a theoretical dosage model based on physiological data and attenuation effects. The aim of the study was to find a dosage calculation method that gave the same image quality for children of all ages as well as for adults. The results showed that the dosage method based on body weight is the only one of the four methods that does not exhibit an age-dependent variation in image quality and therefore this method is recommended.

Adolescent

Influence of breathing pattern on transcutaneous oxygen and carbon dioxide tension during histamine provocation in children with bronchial asthma.

The influence of the breathing pattern on transcutaneous blood gases was evaluated in 18 boys and 8 girls 7-18 years of age, with bronchial asthma, during bronchial provocation with histamine-HCl. Transcutaneous oxygen tension (tcPO2), carbon dioxide tension (tcPCO2) and the breathing pattern assessed by the transthoracic impedance technique were continuously monitored during the provocation. At reaction, when the fall in the forced expiratory volume in 1 s (FEV1) was 20% or more, the tcPO2 fell by 15% or more below the baseline in 22/26 and by 20% or more in 14/26 children. In some children, a marked fall in the tcPO2 was already noted after the saline inhalation and the first histamine dose steps without simultaneous changes in the FEV1. This early fall in the tcPO2 correlated to changes in the breathing pattern and was interpreted as a sign of compensatory hypoventilation secondary to the hyperventilation observed during the inhalations. We conclude that transcutaneous oxygen tension can be used as an indicator of a bronchial reaction during bronchial provocation tests in children only if one takes account of the fact that the breathing pattern during the inhalation of the challenge compound per se has an effect on the oxygen tension.

Administration, Inhalation

Respiratory resistance and transcutaneous PO2 during histamine provocation in children with bronchial asthma.

Bronchial reactivity was assessed in 66 children with bronchial asthma (aged 8-15 years) by provocation with histamine-HCl during a symptom-free period. A significant bronchial reaction to histamine was defined as a 50% increase in the resistance of the respiratory system (Rrs) determined by the forced oscillation technique. The provocative dose causing a 50% increase in the Rrs (PD50Rrs) was interpolated from the log dose-response curve. The mean PD50Rrs was significantly lower in children with asthma (0.22 mg/mL) compared with a group of healthy children in the same age range (1.55 mg/mL) (P < 0.001). In children with clinically severe asthma, the mean PD50Rrs was lower (0.13 mg/mL) than in children with mild asthma (0.34 mg/mL) (P < 0.001). Transcutaneous PO2 (PtcO2) was monitored in 25 of the children with asthma. In this group the proportion of mild and severe asthma, the baseline lung function variables, and the PD50Rrs were not significantly different from those of the whole group of children. During the reaction, the PtcO2 fell on average by 29% of the baseline value (P < 0.001); in 88% of the children, the fall in PtcO2 was 20% or more of the baseline value. We conclude that histamine provocation tests using the forced oscillation technique and transcutaneous PO2 to assess a bronchial reaction have a good discriminatory capacity for different degrees of clinical severity of asthma in children.

Adolescent

Transcutaneous blood gas monitoring during salbutamol inhalations in young children with acute asthmatic symptoms.

The effect of salbutamol inhalations on transcutaneous blood gases was investigated in 23 children (aged 11 months-2.5 years) with asthmatic symptoms. After one salbutamol inhalation there was a mean increase in transcutaneous PO2 (tcPO2) of 0.5 kPa (P less than 0.01); after a second dose given 30 minutes later, the mean increase was 1.2 kPa (P less than 0.001). The increase in tcPO2 after only one dose of salbutamol was significantly correlated to age (P less than 0.01). No such correlation was observed after a second dose. The overall increase in tcPO2 after two salbutamol inhalations showed a negative correlation to the duration of the current symptomatic period (P less than 0.05). We conclude that salbutamol inhalations have beneficial effects in young children with acute asthmatic symptoms, even below the age of 18 months, provided that an adequate dose reaches the lung and preferably at an early stage of obstruction.

Acute Disease

Evaluation of cerebrospinal fluid shunt function in hydrocephalic children using 99mTc-DTPA.

The increasing numbers and survival of children with shunt-treated hydrocephalus make it mandatory to refine the methods for cerebrospinal fluid (CSF) shunt function evaluation. Radionuclide shuntography with 99mTc-DTPA, which has proved to be a safe and effective method, was performed in eight children with suspected CSF-shunt dysfunction. Characteristic shuntography patterns were found for proximal and distal CSF-shunt catheter obstruction as well as for overdrainage and normal CSF-shunt function. Shuntography contributed to the explanation of suspected CSF-shunt dysfunction in all children investigated.

Adolescent

Pronounced detrusor hypercontractility in infants with gross bilateral reflux.

In this study the prevalence of bladder dysfunction in 18 children with gross bilateral reflux was investigated via cystometric recordings. In all except 1 infant maximal voiding detrusor pressure was 100 cm. or greater water (range 86 to 244). Pronounced instability during filling (overt instability) with pressure waves above baseline (mean 65 cm. water, range 42 to 194) was found in 9 infants. Another 5 children had evidence to suggest an uninhibited bladder, not manifested as unstable contractions during filling but as covert instability, meaning that the first unstable contraction was transformed into a premature and forceful voiding contraction. The high detrusor pressures found in 18 children with gross bilateral reflux during the voiding phase but also during the filling phase in half of the children suggest that a hypercontractile detrusor may be a contributory factor for the development of reflux even in this age group.

Female

Brain single photon emission computed tomography (SPECT) in neuropediatrics.

The clinical value in neuropediatrics of [99mTc]HM-PAO brain single photon emission computed tomography was preliminary evaluated by the consecutive investigation of 79 children. Planned epilepsy surgery was the most common indication for the investigation. In 56 children investigated because of epilepsy, SPECT yielded relevant information in 79% of cases examined. The corresponding figures for magnetic resonance imaging and CT were 49% of 35 and 36% of 56 cases, respectively. All 22 children with an epileptic focus, ascertained by freedom from seizures after removal of the area or by consistent neurophysiological and neuroradiological findings, also had abnormal perfusion in the relevant area. Twenty-three children were examined because of neurological signs and symptoms other than epilepsy. SPECT findings were useful for elucidating neonatal brain impairments. Hypoperfused areas in the brain of asphyxiated infants and in posthemorrhagic hydrocephalus corresponded to neuroradiological and autopsy findings. SPECT was found to be an excellent tool when analysing cerebrovascular accidents. In cases with signs and symptoms of a diffuse severe encephalopathy, SPECT did not clarify the etiology but provided information on the distribution of the lesions and probable underlying pathophysiological mechanisms.

Adolescent

Psychological and respiratory physiological effects of a physical exercise programme on boys with severe asthma.

Ten boys 9-12 years of age with severe perennial asthma participated in a physical exercise programme lasting 8 months. Pulmonary function and psychological tests were performed before training, immediately after, and one year after the end of the exercise programme. Static lung volumes, flow-volume variables and histamine tolerance were used as indicators of pulmonary function. Ego structure, body image, social development and concentration capacity were used as indicators of personality development. Before the study, the group had high FRC (p less than 0.05) and RV (p less than 0.001), low FEV1, MEF50 and MEF25 (all p less than 0.001) and low histamine tolerance. They showed marked disturbances in their personality development with low scores in psychological variables. During the training period, MEF50 and MEF25 increased slightly (p less than 0.01). Marked improvement was observed in all psychological variables (p less than 0.001). The positive effects remained during the following year. The marked and lasting improvement in personality development was regarded as an essential factor behind the more modest positive clinical and pulmonary function changes. The results emphasize the importance of including exercise programmes in the treatment of children with asthma.

Asthma

Respiratory sequelae and lung function after whooping cough in infancy.

The lung function of 31 children, aged 6-13 years, who had whooping cough as infants and 32 control children matched for age, sex, and residence area were compared in a community based cohort study. Family history of obstructive airway disease, smoking habits in the family, atopy, and other background factors examined were similar in the two groups. The ratios of recalled repeated acute respiratory infections did not differ among the groups. Children in the control group were slightly more involved in physical activities. History of obstructive airway disease, findings on chest radiography, and distribution of immunoglobulin concentrations, including IgE, did not differ significantly. Lung function before and after exercise and after inhalation of salbutamol were not different. No impairment of small airways was detected. Our data do not support the hypothesis that whooping cough in itself is a causal factor for later obstructive respiratory disease.

Adolescent

Hypoxia reinforces laryngeal reflex bradycardia in infants.

The laryngeal chemoreflex involves bradycardia, apnea, swallowing and peripheral vasoconstriction. This reflex was studied in twelve infants, aged 5 days-28 weeks, who had sustained an apparent life-threatening event or were siblings of infants who had died of the sudden infant death syndrome. The bradycardic and apneic components of the reflex were found to be significantly, and sometimes powerfully, reinforced when elicited by pharyngeal water instillation during acute, mild hypoxia (transcutaneous PO2 4.6-8.3 kPa). Apnea duration during normoxia was 0.7-15 sec, and during hypoxia 2-30 sec. Heart rate change ranged from +26% to -21% during normoxia, as compared with -4% to -63% during hypoxia. The percentage change in heart rate was found to inversely correlate with the transcutaneous PO2-level prevailing when the reflex was elicited. The conclusion is that there is a significant reinforcement of the cardiorespiratory adjustments when the laryngeal reflex is activated during simultaneous excitation of the peripheral arterial chemoreceptors. One infant, showing a particularly strong increase of the cardiorespiratory response to laryngeal receptor stimulation during hypoxia, later died of sudden infant death syndrome.

Blood Gas Monitoring, Transcutaneous

Untreated bacteriuria in asymptomatic girls with renal scarring.

Recurrences of bacteriuria after treatment occur in 50% to 80% of asymptomatic patients. Previous experience with short-term treatment as well as long-term prophylaxis has been disappointing, with a significant risk of infections, ie, development of symptoms after treatment. Results with nontreatment are described in this report with reference to clinical course, renal growth, and glomerular filtration rate in 26 asymptomatic girls with established renal scarring and bacteriuria. Acute pyelonephritis was not seen in those with continuing bacteriuria or spontaneous clearance. Neither in scarred nor in unscarred kidneys did the duration of bacteriuria influence renal growth or glomerular filtration rate. Asymptomatic patients with bacteriuria may gain from nontreatment and may have a reduced risk of pyelonephritic attacks.

Adolescent

The epidemiology of sudden infant death syndrome and attacks of lifelessness in Sweden.

Infants who died showing the syndrome of sudden infant death (SIDS) and infants who survived attacks of lifelessness (AL) were examined in a prospective epidemiological multicentre study over 24 months covering close to 40% of all births in Sweden. Seventy SIDS cases and 34 cases of AL were observed, giving an incidence for SIDS of 0.94/1000 and for AL of 0.46/1000. This SIDS incidence is higher than that observed during the seventies. The boy/girl ratio was 1.4:1 for SIDS and 1.6:1 for AL. The age distribution for AL resembled that for SIDS. Similarities were also seen with regard to place of occurrence. Sixty per cent of the SIDS cases occurred during the daytime/evening. Twenty-nine per cent of the infants with AL had more than one apneic spell during the three-day-period around the attack, indicating a period of respiratory instability, but only 12% had such spells later on. None of the infants who had had AL died from SIDS. The possible relationship between AL and SIDS is discussed.

Age Factors

Transcutaneous oxygen and carbon dioxide levels and a clinical symptom scale for monitoring the acute asthmatic state in infants and young children.

Measurement of transcutaneous PO2 and PCO2 in addition to a clinical symptom grading system was used to monitor the acute asthmatic attack in children under two years of age. tcPO2 was lowered already at signs of mild obstruction and decreased in parallel with clinical deterioration. tcPCO2 was almost unchanged at mild to moderate obstructive symptoms. With clinical deterioration tcPCO2 rose steadily. An increase of the oxygen concentration to 30-40% in the inspired air increased tcPO2, on the average by 70%, but did not change the tcPCO2, level. Continuous recording of tcPO2 and tcPCO2 as well as the clinical grading system are valuable tools when monitoring severely obstructive infants and young children.

Acute Disease

Long-term follow-up of infants under intensive care with tracheotomy during the period 1956-1965.

Twenty-seven infants who survived intensive care during early infancy in the pioneering period of neonatal intensive care (1956-1965) were investigated after 8-17 years. The selection criterion was maintenance of a tracheotomy for more than 15 days during the first 12 months of life. A variety of clinical, physiological, radiological and psychiatric sequelae was found. Respiratory symptoms were the dominating problem during the post-tracheotomy period. The long-term follow-up revealed that these symptoms had a strong tendency to subside. At the time of the follow-up, as many as 20 children (74%) did not experience any functional impairment.

Child Development

Forced oscillation technique and maximum expiratory flows in bronchial provocation tests in children.

Variables obtained with the forced oscillation technique (total respiratory resistance and impedance at 2, 4 and 12 Hz) and with the forced vital capacity manoeuvre (FVC, FEV1, MMEF, MEF75, MEF50, MEF25) were used in the evaluation of the bronchial allergen challenge test in 2 groups of asthmatic children. Each method was applied in 15 provocation tests and the changes of the different variables, allowing for their respective variations, were compared with the clinical assessment. Agreement with the clinical evaluation was found in 15 of 15 occasions with the forced oscillation technique and in 12 of 15 occasions with the forced vital capacity manoeuvre. With the forced oscillation technique a bronchial reaction was detected in 6 of 10 patients at 1/10 of the allergen concentration that gave positive clinical signs and the single most sensitive variable was resistance determination at 4 Hz, with significant change in 5 of 10 cases. The forced vital capacity manoeuvre allowed detection of a bronchial reaction preceding clinical signs at a tenfold lower allergen concentration in 2 of 9 cases and the most sensitive variables were FEV1 and MEF25.

Adolescent