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Biomedical subjects

B Lindquist

Publications and source records attributed to B Lindquist.

At least 37 records · Page 2Linked to original sources

Identification of the 11,12-dihydro-11,12-dihydroxybenzo(a)pyrene as a major metabolite produced by the green alga, Selenastrum capricornutum.

Benzo(a)pyrene metabolites were isolated after incubation of [14C]-benzo(a)pyrene with the green alga, Selenastrum capricornutum. A significant amount of radioactivity chromatographed in the dihydrodiol region which did not coelute with any of the previously identified dihydrodiol metabolites isolated from this system. Following characterization by mass spectrometry, fluorescence spectroscopy, and high pressure liquid chromatography, this metabolite was identified as the cis-11,12-dihydro-11,12-dihydroxybenzo(a)pyrene. This metabolite has not been identified previously as a metabolite formed in a plant system.

Benzo(a)pyrene

Effects of adjuvants to local anaesthetics on their duration. II. Studies of some substituted dextrans and other macromolecules in rat infraorbital nerve block.

The effects of adding various macromolecular substances to 2% prilocaine on duration of rat infraorbital nerve block were investigated. The tested substances consisted of dextrans with lipophilic or charged substituents as well as other neutral or highly charged macromolecules. Most of the adjuvants caused significant prolongations of sensory block. For substituted dextrans the duration of sensory block degree 3 amounted to between 120% (3% capryldextran II) and 350% (3% carboxymethyldextran) in comparison to prilocaine plain. The corresponding values for hydroxypropylstarch (3%) alginic acid (0.5%), beta-cyclodextrin (1.5%) and hyaluronic acid (0.25%) were about 170%, 285% and 380%, respectively. The results suggest that the increased duration of local analgesia by prilocaine is related to increased viscosity of the solution produced by the macromolecular compounds. The mechanism seems to be of a physical character, and hyaluronic acid seems to be worthy of further studies.

Alginates

Effects of adjuvants to local anaesthetics on their duration. III. Experimental studies of hyaluronic acid.

The effects of addition of hyaluronic acid (sodium hyaluronate, Healon) to different local anaesthetics of the amide type on the duration of sensory or motor blocks following various regional anaesthetic procedures were studied in animal experiments. In the rat infra-orbital nerve block model, the addition of 0.1-0.5% hyaluronic acid (HA) to 2% prilocaine increased the duration of sensory block of varying degrees in a dose-dependent way by up to 500% of values obtained with plain prilocaine. The duration of degree 5 blocks produced by 0.5% etidocaine and 0.5% bupivacaine was also significantly prolonged when 0.4% HA was included to 206% and 282% of control, respectively, while blocks induced by 2% lidocaine were prolonged to 123% of control. The duration of motor block following spinal anaesthesia in the mouse was prolonged in a dose-dependent way when HA was added to prilocaine, bupivacaine and etidocaine. For solutions containing 0.4% HA, prolongations to 254%, 166% and 134% of control, respectively, were obtained. A concomitant increase of latency to onset of block and failure rate occurred with increasing concentrations of HA. The duration of corneal anaesthesia in the rabbit increased by 57% and 44% when 0.3% HA was added to prilocaine and bupivacaine, respectively. The duration of infiltration anaesthesia was not affected by the addition of HA to the local anaesthetic solutions. Addition of HA had no effect on the onset, depth and duration of prilocaine-induced block of the nervous transmission in vitro. The duration of infra-orbital nerve block and spinal anaesthesia shows a significant relation to the relative viscosity of the local anaesthetic solution.

Anesthetics, Local

Denture stomatitis in nursing home patients.

All 352 patients in two nursing-homes in Orebro were examined. In one of the homes microbiological tests could be done on the patients with full upper dentures. The samples were taken both from the denture and the oral mucosa. Candida albicans, Yeast, Staph. aureus, B-hemolytic streptococci and Klebsiella/Enterobacter were controlled. In samples from the oral mucosa a correlation was found between stomatitis, Candida albicans and Staph. aureus (P less than 0.01). A weak correlation was also found between stomatitis and Klebsiella/Enterobacter (0.01 less than P less than 0.05). In samples from the dentures there were only a weaker correlation between Stomatitis, Candida albicans and Staph. aureus (0.1 less than P less than 0.05).

Aged

Acid-base homeostasis of low-birth-weight and full-term infants in early life.

Renal tubular function tests on hydrogen ion excretion capacity and concentration capacity performed during the first month of life show that these functions are not fully developed although they may be adequate for the needs of the breastfed infant. A positive net acid balance due to a less well-developed renal acidifying capacity is a fairly common situation during the first weeks of life. Late metabolic acidosis could thus be demonstrated in a frequency of up to 20% in preterm babies depending on the quantity as well as the quality of the dietary protein; the corresponding figure in term babies was about 5%. Furthermore, it must be taken into account that the elimination of one metabolite may affect the efficiency of other excretory mechanisms. It could thus be shown that during an acid loading period, the maximum renal concentration capacity falls from preloading values of 500-600 to 300-400 mOsm/1. When a pitressin load was superimposed on an acidification test, the net acid excretion was reduced, especially in infants on a high protein intake. Therefore, if in the immature infant the composition of dietary intake is inappropriate as to the protein intake and/or solute load, the limit of capacity of certain renal tubular functions may be exceeded, especially under conditions of stress, and this could result in homeostatic disturbances, i.a. of the acid-base balance.

Acid-Base Equilibrium

Growth in relation to protein intake of low birth weight infants.

In a prospective longitudinal study of 48 very low birth weight and preterm infants with mean birth weight 1385 +/- 343 g and gestational age 30.8 +/- 2.9 weeks an assessment was made of the impact of varying the protein intake in the postnatal period from the 3rd to 7th week of life. The infants were randomly allocated to one of three dietary groups with isocaloric energy supply but different protein content, i.e. human milk (1.6 g/100 kcal), formula 1 (2.3 g/100 kcal) and formula 2 (3.0 g/100 kcal). In the human milk group 12 of 18 infants were fed their own mother's breastmilk. During the study period the mean weight gain was slight higher in the infants fed formula. There were no group differences in S-albumin but B-urea-N and B-base deficit were significantly higher in formula-fed infants compared to infants fed human milk. After the study period that lasted to about 20 weeks of age the slope in weight gain remained slightly higher for formula fed infants, whereas the gain in body length and hear circumference was equal in all three groups. After around 8 months of age there was no difference in any growth parameter. Neurodevelopmental examinations showed no group differences during the follow-up period to 2 years of age. With few exceptions breastmilk-preferably from their own mothers-was adequate for both early and longterm growth and development of the very low birth weight infants in this population.

Body Weight

A comparative study of varying protein intake in low birthweight infant feeding.

In a prospective longitudinal study of 48 very low birthweight and preterm infants with mean birthweight 1 385 +/- 343 and gestational age 30.8 +/- 2.9 w an assessment was made of the impact of varying the protein intake in the postnatal period from the 3rd to 7th week of life. The infants were randomly allocated to one of three dietary groups with isocaloric energy supply but different protein content--i.e. human milk (1.6 g/100 kcal), formula 1 (2.3 g/100 kcal) and formula 2 (3.0 g/100 kcal). In the human milk group 12 of 18 infants were fed their own mother's breastmilk. During the study period the mean weight gain was slightly higher in the infants fed formula 1 and 2. There were no group differences in S-albumin whereas B-urea-N and B-base deficit were significantly increased in the formula fed infants in comparison to infants fed human milk. After the study period until around 15 weeks of age the slope in weight gain remained slightly higher for formula fed infants. However, the gain in body length and head circumference was equal in all three groups. After around 8 months of age there was no difference in any growth parameter. Neurodevelopmental examinations showed no group differences during the follow-up period to 2 years of age.

Acid-Base Equilibrium

Early detection of preschool health problems--role of perinatal risk factors.

To evaluate a perinatal risk-grouping system, 1 262 4-year-old children went through a comprehensive health examination. A total of 41.5% of the newborns were included in the wide criteria of risk, which were more common among boys and among children of the youngest and oldest mothers. Among the 4-year-old, the frequency of significant physical health problem was 15.8%, including 10.1% visual disturbances and 2% neurological disorders. In some combinations of risk groups and later health problems there were statistically significant correlations, e.g. regarding prematurity and cerebral irritation vs. cerebral palsy, but not sufficient to serve its purpose as a screening instrument. Even the accumulation of especially serious events in the perinatal period gave no clue to later neurological disorders. The addition of low socioeconomic status as a perinatal risk did not influence the outcome either. The reasons for the weak correlation between perinatal risk factors and later outcome of health disorders and handicaps are discussed, and it is concluded that to detect children with health problems, there seems to be no acceptable alternative to a comprehensive health surveillance as part of a general health service programme of all children, including clinical examinations and screening procedures by well trained personnel.

Age Factors

Recent views on infant nutrition.

Particular problems under discussion in the field of infant nutrition today are the following. (1) The frequency of breastfeeding including the effect of promotion to uncrease it. (2) The protein requirement of low birth weight infants including relevant parameters for evaluation of the requirement. Recent studies indicate that the protein requirement of low weight is only slightly higher (or may be the same) as that supplied by breast milk. (3) The tolerance for intake of certain nutrients in early infancy - mainly protein and minerals - in relation to the development of organ functions, including homeostatic disturbances that may arise when the tolerance is exceeded. Adverse effects of a too high protein intake are particularly acidosis and increased osmolar load on kidney function. Excess mineral adds to the renal solute load, implying a threat to water balance. (4) The introduction of Beikost, when and why, and (5) Atherosclerosis as a problem for the pediatrician. The need for identification of risk factors, especially screening for hyperilipidemia, in early life and for recommendation of dietary measures instituted in early childhood has to be further studied.

Acidosis