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Biomedical subjects

C Engström

Publications and source records attributed to C Engström.

At least 19 recordsLinked to original sources
PubMed1994

Growth effects of instantaneous change in mandibular position: experimental study.

PURPOSE: To investigate the mandibular growth pattern in rats during adolescence after altering the position of the mandible in the frontal plane instanteously by two surgical procedures. METHODS: Mandibular morphology during growth was recorded by cephalometric methods during the 3-week experimental period. RESULTS: All procedures tested caused an altered mandibular morphology. An overall change was found in the shape of the mandible in the experimental groups, with the jaw being more square compared with the rectangular form found for the mandible in the control group. Condylar growth was abnormal and the cartilage of the experimental groups showed a reduced thickness and distorted morphology, indicating disturbed cellular activity. CONCLUSION: In view of the findings, it was concluded that considerations to instantaneously alter the mandibular position during adolescence may not be advisable.

Age Factors↗
PubMed1994

Thyroid function and root resorption.

The regulation of degradative activity such as phagocytosis and bone resorption in the periodontal region is greatly influenced by factors controlling general bone modeling. The purpose of this study was to determine if thyroxine has any influence on the occurrence of force-induced root resorption. Young male rats were divided into three groups: a group of normal rats, a control group in which appliances were placed, and an experimental group in which appliances were placed and I-thyroxine was administered (5 micrograms/kg bw for 12 days). Root resorptions were induced by orthodontic force on the maxillary incisors. Fewer force-induced root resorption lesions occurred in the thyroxine group than in the control group. Alkaline phosphatase activity in the thyroxine group was significantly different from the normal and control groups. Thus, the decrease of resorptive lesions in the thyroxine group seemed correlated to a change in the bone modeling process, especially as related to the resorption activity.

Alkaline Phosphatase↗
PubMed1994

Anticipation in Swedish families with bipolar affective disorder.

Anticipation describes an inheritance pattern within a pedigree with an increase in disease severity or decrease in age at onset or both in successive generations. The phenomenon of anticipation has recently been shown to be correlated with the expansion of trinucleotide repeat sequences in different disorders. We have studied differences of age at onset and disease severity between two generations in 14 families with unilinear inheritance of bipolar affective disorder (BPAD). There was a significant difference in age at onset (p < 0.008), in episodes per year with (p < 0.006) and without (p < 0.03) lithium treatment, and in total episodes per year (p < 0.002) between generations I and II. Furthermore, there was a highly significant correlation (p < 0.001) in age at onset between generations I and II. No evidence for specific paternal or maternal inheritance was found. We found evidence of anticipation and could rule out ascertainment bias or some other artefact. Anticipation is thus an inheritance pattern in BPAD which suggests that the expansion of trinucleotide repeat sequences is a possible mode of inheritance in BPAD.

Adolescent↗
PubMed1992

Influence of masticatory muscle function on craniofacial growth in hypocalcemic rats.

The aim of this study was to investigate the influence of low masticatory function on the craniofacial growth pattern in rats fed a low calcium and vitamin D deficient diet. Male growing rats were divided randomly into three groups: the Normal Hard Diet group, the Deficient Soft Diet group, and the Deficient Hard Diet Group. Lateral cephalograms were taken at days 0, 14 and at the end of the experiment, day 28. The craniofacial growth pattern was altered by an upwards rotation of the viscerocranium (orthocranialization) in the Deficient groups and, the total skull lengths were shorter than in the Normal Hard Diet group. The viscerocranium in the Deficient Soft Diet group was in an even more orthocranial position than in the Deficient Hard Diet group and the antegonial notch was shallower. This indicates that an induced disturbance of craniofacial morphology due to metabolic bone disease during growth is accentuated by a low masticatory function.

Animals↗
PubMed1991

Alcohol-related expectancies for self and others reported by alcoholic men and women.

A questionnaire used by Rohsenow in 1983 was administered to 87 alcoholic men and women taking part in rehabilitation programs at local Swedish outpatient rehabilitation clinics. The purpose was to explore their alcohol-related expectancies for themselves and for others and to compare these with the results from other similar studies in other cultures. The answers, scored according to Rohsenow's eight factors, indicated that alcoholics expected larger positive and negative effects for others than for themselves. This discrepancy was slightly modified by such variables as sex, age, and drinking habits. Alcoholics in Sweden seem to have alcohol-related expectancies similar to those of social drinkers both in Sweden and in other Western countries.

Adult↗
PubMed1991

Parathyroid hormone and enamel formation in rat maxillary incisors.

Parathyroid hormone (PTH) plays an important role in regulating calcium in serum. It is also known to affect bone and dentin formation. The purpose of this investigation was to evaluate enamel formation in normal rats receiving added PTH. It is in two parts: a pilot study where a known method was tested, followed by the main study where the rats were given different doses of PTH. The enamel was examined in both studies and in the main study the ameloblasts were also investigated. Contradictory results were seen. In the pilot study, severe enamel aberrations occurred, while no divergence from normal amelogenesis was noted in the main study. A factor causing the disparate results was the use of a hard tissue marker (oxytetracycline) in the pilot study. It can be concluded that injections of PTH in doses that affect bone and dentin did not cause any changes in normal enamel formation.

Acid Phosphatase↗
PubMed1989

The effect of thyroxine on craniofacial morphology in the growing rat. Part I: A longitudinal cephalometric analysis.

The wide therapeutic use of hormones enhances the importance of detailed knowledge of the effects on skull growth. Thyroxine is known to regulate maturation of cell populations and long bone growth, but the influence on craniofacial bone remodelling is still obscure. One side effect of substitution therapy with thyroxine in children is premature closure of cranial sutures. The aim of the present study was to describe longitudinally the effect of different serum levels of thyroxine on craniofacial growth. In young rats injected with 20 micrograms/kg b.w. l-thyroxine for 28 days a change was found in craniofacial morphology measured by a cephalometric technique. A decrease in length of the viscerocranium was evident after 14 days, and occurred in connection with raised serum levels of thyroxine. In contrast, cranial base growth was increased between day 14 and 28 and also a catch-up growth in the viscerocranium was observed during this period. This observed change occurred after the induced peak in levels of thyroxine in serum had subsided. The inhibited forward directed growth of the viscerocranium was consistent with the fact that the skull in the thyroxine group developed a klinorhycial form in contrast to the normal orthocranialization. Thus, the craniofacial growth pattern was influenced by variations in the serum level of thyroxine. The effects of thyroxine on skull growth sites observed are consistent with reported effects of low dose of thyroxine on long bone growth.

Animals↗
PubMed1988

Histochemical analysis of masticatory muscle in the growing rat after prolonged alteration in the consistency of the diet.

Changes in muscle function induce alteration in craniofacial bone growth. To study morphological changes after alteration of masticatory function, NADH-TR reductase and myofibrillar Ca2+-activated ATPase were assessed histochemically, after alkaline and acid pre-incubation, in sections from the anterior deep masseter and the anterior digastric muscles. Type IIA, IIB and transitional fibres of the anterior deep masseter but not of the digastric muscle were smaller in a soft-diet group than in a normal-diet group. There was a small percentage of type IIA fibres and a large percentage of type IIB fibres in the anterior deep masseter in the soft-diet than in the normal-diet group. The elevator muscles do not encounter the same functional demands on a soft as on a normal diet, and this causes different biting and chewing loads, which may in turn induce skeletal changes.

Animals↗
PubMed1988

Effect of orthodontic force on periodontal tissue metabolism. A histologic and biochemical study in normal and hypocalcemic young rats.

The relationship between force and degradation activity after application of orthodontic force is still obscure. Of particular clinical interest are the etiologic factors behind excessive root resorptions appearing in connection with orthodontic movement of teeth that has been proposed to be influenced by systemic factors regulating the tissue-degrading activity in periodontal tissues. Thus, the aim was, by histologic and new biochemical methods, to investigate the effect of orthodontic forces on the periodontal tissues in the normal and the hypocalcemic situation with secondary hyperparathyroidism. Root resorptions were induced in upper incisors of normal and hypocalcemic rats by subjecting the teeth to a moderate orthodontic force. In both groups the resorption of the roots occurred consistently in the vicinity of reorganizing areas of the periodontal ligament (PDL) with ongoing degradative activities and alveolar bone resorption. Furthermore, specific cell metabolic changes in alveolar bone and PDL in tension and pressure zones were detected and quantified by biochemical determination of alkaline phosphatase activity. This biochemical quantification of the metabolic changes together with the morphologic observations gave the clinically valuable information that the observed increase in occurrence and severity of root resorptions in moderate hypocalcemia was related to an increase in alveolar bone turnover. This study has shown that root resorptions were clearly related to the degradation process occurring in the vicinity of the hyaline zone and that in the hypocalcemic situation, the increase in root resorptions was related to an enhanced alveolar bone resorption. Thus, factors that minimize the time for resorptive/degradative activity should be discussed in this context rather than force per se.

Alkaline Phosphatase↗
PubMed1988

Effect of bone matrix-derived growth factors on skull and tibia in the growing rat.

Aberration in cranial skeletal morphology during growth due to metabolic bone diseases associated with hypocalcemia is related to abnormalities in cranial suture growth. It was found in previous experimental studies that a changed cranial growth pattern induced by hypocalcemia and secondary hyperparathyroidism was dependent on a decreased bone apposition in viscerocranial growth sites. Of interest was the observation that obliterative osteogenesis occurred with this disturbance. In vitro studies have shown that when bone resorption is stimulated by parathyroid hormone, mitogenic factors for bone cells are released from the matrix. The aim of the current study was to elucidate a possible local regulatory mechanism for bone growth especially with regard to cranial growth. Two groups of young rats were injected daily with 150 micrograms and 750 micrograms respectively of bone matrix-derived growth factor preparation (BMDGF) for 2 weeks. By using cephalometric analysis, the BMDGF administration was shown to alter skull morphology during growth. Since the high doses of BMDGF caused markedly more changes than the low dose, the overall effect on craniofacial growth seemed to be dose dependent. The high dose of BMDGF induced a decrease in cortical bone apposition found in this region, as well as in the diaphysis of the tibia. Also a change in position of the viscerocranium in relation to the cranial base was found in the BMDGF-treated rats: the flexure between the viscerocranium and the cranial base being greater compared with the normal skull. This change in relationship seemed to be related to the enhanced bone apposition found in the viscerocranial sutures of BMDGF-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

BM-5, a centrally active partial muscarinic agonist with low tremorogenic activity. In vivo and in vitro studies.

The acute and chronic effects of the centrally active oxotremorine analog, BM-5, [N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)-acetamide] were examined in rats and mice. In vivo studies in mice and rats indicated that this compound is a partial muscarinic agonist with large regional differences in its efficacy: BM-5 produced low tremor in doses which evoke full salivary response. The maximal tremor response to BM-5 was much smaller than that produced by oxotremorine, while the maximal salivary response to BM-5 was greater than that evoked by oxotremorine. The tremor response to BM-5 was bell-shaped, the peak dose being around 2 mg/kg. In contrast, the salivary response increased with increasing doses of BM-5. The apparent muscarinic antagonist properties of higher doses of BM-5 were specific to the striatum in which BM-5 (0.05-10 mg/kg) caused significant decreases in the level of acetylcholine while these levels were unaltered in the cerebral cortex, hippocampus, and brainstem. Pretreatment of rats with BM-5 (5 mg/kg) also prevented the increase in striatal acetylcholine induced by oxotremorine (0.75 mg/kg). Chronic treatment of mice with BM-5 (0.2-2 mg/kg) for 14 days also showed that BM-5 at higher doses, behaved as an antagonist, since it caused supersensitivity to oxotremorine on the tremor response. In addition, the number of receptor sites, as measured by binding of 3H-3-quinuclidinyl benzilate (3H-3-QNB), was increased in the striatum while no similar increase was observed in other brain areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1986

Iodinated derivatives of the vasoactive intestinal polypeptide (VIP) are agonists at the cat pancreas and the rat submandibular salivary gland.

Porcine VIP was iodinated by the chloramine-T method. The reaction products, which were separated by high pressure liquid chromatography, included residual native VIP, oxidized VIP and at least two iodinated VIP species. The iodo-VIP derivatives were recognized by antibodies raised against VIP and by VIP receptors. Furthermore, they appear to be approximately equipotent agonists to VIP in activating the adenylate cyclase in membranes from the rat submandibular salivary gland and in the stimulation of pancreatic secretion in vivo.

Adenylyl Cyclases↗
PubMed1985

Jaw morphology in edentulous individuals: a radiographic cephalometric study.

The jaw morphology in the mandible and maxilla was studied by cephalometric analysis in two groups of edentulous subjects and in two groups of individuals in possession of all teeth. The predominating facial type in these groups was the orthognathic type. The alveolar bone height differed significantly between men and women in the edentulous groups but not in the subjects in possession of all teeth. Thus, there seemed to be a sex difference in alveolar bone diminution after extraction of all teeth. The gonial angle was significantly greater in both men and women in the edentulous groups than in either sex in the groups in possession of all teeth. Thus, the basal bone morphology in the mandible seemed to be changed in the same manner in both sexes in the edentulous groups after extraction of all teeth, in contrast to the alveolar bone diminution. Indications were found that the gonial angle might be age related. The chin angle as such was found to be less than 60 degrees in the majority of edentulous individuals which makes this value seem to be of minor importance when selecting edentulous individuals for surgical deepening of the vestibular sulcus.

Adolescent↗