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Biomedical subjects

D Johnsen

Publications and source records attributed to D Johnsen.

At least 19 recordsLinked to original sources
PubMed1993

Intra- and inter-individual variations in energy expenditure of 14-15-year-old schoolgirls as determined by indirect calorimetry.

Eleven 14-15-year-old schoolgirls were investigated four times within 1 year to determine variations in energy expenditure between individuals (inter-individual variability) and within subjects (intra-individual variability). Indirect calorimetry was used to determine metabolic rates in the fasting and resting state (RMR), and during physical activities which were grouped into standardized and non-standardized activities. Analyses of variance supplied information about intra- and inter-individual variabilities of rates of energy expenditure. The mean resting metabolic rate in adolescent girls was 4.41 (SD 0.40) kJ/min. The overall coefficient of variation (9.1%) was approximately twice as high as the mean coefficient within subjects (4.3%). The reproducibility of the RMR of the girls was high (significant F value of variance analysis), even over a prolonged investigation of 1 year. This seemed to depend primarily on the constant body weight during the period of investigation. A workload of 30 W on a bicycle ergometer and walking at an individually chosen speed did not reveal significant differences between inter- and intra-individual variabilities of energy metabolic rates. However, in most non-standardized activities, e.g. relaxation at home, washing dishes and vacuum cleaning, inter-individual variability was significantly higher than intra-individual variability. There are true differences in energy expenditure rates between subjects which may be demonstrated by duplicated measurements. Conclusions on future experimental design were drawn, where differences between groups rather than between individuals are to be studied.

Adolescent↗
PubMed1989

Baby bottle tooth decay (BBTD): issues, assessment, and an opportunity for the nutritionist.

Baby Bottle Tooth Decay (BBTD) is a rampant form of caries affecting the maxillary incisors, and frequently the molars, that occurs before the age of 2 years and is of growing concern. BBTD is a nutritional disorder whose outcome is carious teeth. Treatment involves extensive and expensive restoration of teeth or extraction of teeth associated with physical restraint, sedation, or general anesthesia in a hospital. This review of several issues regarding BBTD includes description, etiology and pathogenesis, prevalence, background factors, treatment, timing for intervention, existing strategies, and research opportunities. The disease is of significance to the nutritionist because it is totally preventable and occurs at an age when many children have seen a nutritionist (e.g., in a WIC program) but may not have seen a dentist. The dietetic practitioner can identify children at risk, determine awareness by the parent, and establish a behavioral contract with the parent. The practitioner needs to succeed for only a brief time to prevent BBTD.

Dental Caries↗
PubMed1988

Risk factors in the population of the GDR-MONICA Study (1983/84).

The GDR-MONICA project comprises 25 administratively defined areas with a population of nearly two million people aged 25-64. Data from the first random sample survey are reported here. The survey gathered information regarding risk factors, dietary behaviour, physical activity and psychosocial factors from 11,281 persons aged 25-64. The average risk factor levels were high in the population: The mean casual blood pressure was 140/88 mmHg and 138/86 mmHg for men and women respectively. In both sexes the mean total cholesterol level exceeded 6.1 mmol/L, and the mean body mass index (BMI) was just over 26.0. The study population consumed, on average, excessive amounts of energy, fat, alcohol, and sodium, and too few carbohydrates. Preliminary conclusions regarding unfavourable trends in risk factor levels have been drawn by comparing the present data with other recent reliable epidemiological studies.

Adult↗
PubMed1984

Distribution of enamel defects and the association with respiratory distress in very low birthweight infants.

Although dental defects have long been observed among surviving pre-term infants, only few systematic studies address this problem. In a clinic limited to recall of infants of very low birthweight (less than 1.5 kg), enamel hypoplasia of primary incisors was found in 14/67 (21%) children, and enamel opacities were found in an additional 31% of the children. In contrast, enamel hypoplasia and opacities were found in 4% and 22%, respectively, of a control group of 46 normal birthweight children. The difference was significant (p less than 0.05) for the hypoplasia but not for the opacities. Primary incisor enamel hypoplasia was more commonly noted in maxillary central incisors than in lateral incisors (X2 = 28.0, p less than 0.01). Furthermore, hypoplasia was more common in maxillary incisors than in mandibular incisors (X2 = 48.4, p less than 0.01). In infants with dental defects, there was no significant correlation with pregnancy risk factors, gestational age, birthweight, septicemia, first-week caloric intake, serum bilirubin, or calcium. Infants with enamel hypoplasia were more likely, however, to have severe respiratory distress syndrome (X2 = 7.2, p less than 0.01), than infants with unaltered enamel. Central incisor edge involvement may indicate post-natal processes and/or a systemic disturbance extending back to the middle trimester of pregnancy.

Child, Preschool↗
PubMed1982

Quantitative assessment of intrapulpal axon response to orthodontic movement.

Nerve fiber changes are of potential concern during tooth movement. Quantitative and qualitative assessments using electron microscopy of nerve fibers entering the tooth give an indication of change in the remainder of the pulp. Eight healthy mandibular first premolars were selected from four subjects, so that respective pairs had open apices and short-term movement, open apices and long-term movement, closed apices and short-term movement, and closed apices and long-term movement. These were compared to forty-nine untreated control teeth. No significant differences in myelinated or unmyelinated axon number were observed between experimental and control teeth. Altered myelin figures, possibly degenerating, were observed in only a small percentage of axons in teeth moved for a short period. No alterations were observed in teeth moved for long periods. It is concluded that intrapulpal axon alterations are minimal and not progressive with conservative orthodontic tooth movement.

Axons↗
PubMed1981

Nitrous oxide-induced myeloneuropathy: report of cases.

The development of neurologic symptoms, especially a myeloneuropathy, remains a serious hazard of nitrous oxide exposure. The need to use it in a well-ventilated environment with a scavenger system and the avoidance of its self-use are clear from the cases reported. The findings of the questionnaire disclose that the majority of dentists have experienced none of these problems while using nitrous oxide in a professional manner; however, self-use of nitrous oxide, with its potential neurologic sequelae, may be a serious problem among dental personnel.

Adult↗
PubMed1979

Nitrous oxide-induced myelopathy-neuropathy: potential for chronic misuse by dentists.

The myelopathy and neuropathy associated with chronic misuse of nitrous oxide are potentially reversible if the habit is discontinued. This occurred in each of the reported cases, including our case, when it was transiently discontinued. Although a causal relationship between nitrous oxide and this myelopathy-neuropathy has not been proved, the circumstantial evidence is convincing. Both physicians and dentists should be aware of this potentially serious complication of chronic self-administration of nitrous oxide, especially in persons inclined to misuse drugs. Dentists, with their access to nitrous oxide, may be particularly at risk.

Adult↗