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Biomedical subjects

J Knudtzon

Publications and source records attributed to J Knudtzon.

At least 37 records · Page 2Linked to original sources
PubMed1991

Baroreflex responsiveness during hypobaric hypoxia.

Baroreflex responses to graded neck suction during held expiration were studied in five healthy females at sea level and at a simulated altitude of 4,572 m (15,000 ft), with and without oxygen administration. An apparent resetting of the baroreflex was observed during hypobaric hypoxia, but this effect was abolished by oxygen administration. Held expiration alone induced a pulse prolongation in all experimental conditions, however this bradycardiac response was smaller during hypobaric hypoxia than during the two normoxic conditions. When the bradycardic responses of held expiration were subtracted, the baroreflex responses to neck suction were equal in all experimental situations. Similarly, the baroreflex was unaffected by hypobaric hypoxia when the R-R interval prolongations were expressed in percentage of the R-R intervals immediately prior to the neck suction. These data indicate that reduced ambient pressure per se has no influence on the carotid baroreflex control of heart rate.

Adult↗
PubMed1990

[Survey of growth hormone deficiency in children].

When other causes of retarded growth have been ruled out, investigation for classic growth hormone deficiency is indicated in children with reduced velocity of growth and retarded bone development. In cases of classic growth hormone deficiency there is insufficient increase in growth hormone levels after two stimulation tests. However, some short children whose stimulation tests are normal but whose spontaneous growth hormone secretion is reduced or pathological may possibly benefit from growth hormone treatment. Therefore measurements of spontaneous growth hormone secretion and insulin-like growth factor IGF-1 have also been used in the diagnosis of growth hormone-related short stature. The authors present a overview of the diagnosis of growth hormone deficiency in practice based on their own experience.

Growth Disorders↗
PubMed1990

[Survey of growth retardation in children].

Following investigation of 172 children submitted for retarded growth, 34 children obtained a specific diagnosis. 11 of these children had growth hormone deficiency and five had coeliac disease. The remaining 138 children either had genetically determined short stature or their growth and adolescence was constitutionally delayed. 27 prepubertal children received treatment with anabolic steroids, and 17 children were treated with growth hormone. We present a practical approach for the investigation of retarded growth.

Adolescent↗
PubMed1989

[Metabolic diseases causing acidosis in the neonatal period].

The diagnosis of metabolic diseases during the newborn period is difficult because symptoms and findings are similar to those generally encountered in newborn babies who are ill. Moreover, metabolic diseases are often complicated by infections and cerebral hemorrhages. The article presents a short clinical review of metabolic diseases associated with metabolic acidosis in the newborn and discusses appropriate investigations and differential diagnoses. It is important to remember the possibility of metabolic diseases as the cause of metabolic acidosis in the newborn period.

Acidosis↗
PubMed1989

Reduced systolic blood pressure elevations during maximum exercise at simulated altitudes.

Ten healthy female subjects performed maximum exercise on a bicycle in an altitude chamber during normoxia and hypobaric hypoxia simulating altitudes of 2,450, 3,700 and 4,600 m. The increases in systolic blood pressure responses were reduced with the degree of hypobaric hypoxia, whereas heart rate and diastolic pressure responses were unchanged. The increases in blood levels of aldosterone, plasma renin activity, adrenaline, noradrenaline, neuropeptide-Y and vasoactive intestinal peptide were similar at the different simulated altitudes. Angiotensin-converting enzyme and vasoactive intestinal peptide levels were not affected by hypoxia or maximum exercise. The present results suggest that the decreases in systolic blood pressure responses during hypobaric hypoxia could not be explained by altered responses of the measured vasoactive substances from the renin-angiotensin, gastrointestinal, and autonomic nervous systems.

Adult↗
PubMed1988

Turner's syndrome associated with chronic inflammatory bowel disease. A case report and review of the literature.

A 26-year-old woman with Turner's syndrome (45,X/46,X,i(Xq] and Crohn's disease is reported. The inflammatory bowel disease was aggressive with development of intestinal fistulas. Total proctocolectomy was performed, and the patient recovered remarkably well post-operatively. The association of Turner's syndrome and inflammatory bowel disease is reviewed, with special reference to karyotype, severity, mortality and treatment.

Adolescent↗
PubMed1988

Estrogen treatment of excessively tall girls with Marfan syndrome.

Five girls with Marfan syndrome were treated with estrogens for reduction of their final heights. Treatment was started at a chronological age of 12.0 +/- 0.5 years and height of 173.0 +/- 3.1 cm (means +/- SEM). Skeletal age was 12.4 +/- 0.2 years and Bayley-Pinneau final height prediction 186.3 +/- 1.4 cm. Estrogen treatment for 2.0 +/- 0.4 years resulted in final height of 184.1 +/- 0.2 cm (p less than 0.05). The weight increased with 7.8 +/- 2.7 kg during the treatment period. The present results indicate that estrogen treatment may be effective in reducing adult height in girls with Marfan syndrome, but that the effect is probably less than that observed in normally tall girls. This may probably be explained by the rather late start of treatment. No immediate effects on aortic root diameters were observed. Estrogen treatment in Marfan syndrome is discussed with regard to beneficial effects, possible side-effects and optimal age for starting treatment.

Body Height↗
PubMed1988

45,X/47,XY,+13 mosaicism and Crohn's disease.

The unusual karyotype 45,X/47,XY,+13 in an 8.5-year-old girl with the Turner phenotype is described. She displayed none of the phenotypic manifestations of trisomy 13. The patient suffered from Crohn's disease, which is known to be associated with the Turner syndrome. To our knowledge this is the first reported case of Crohn's disease in a patient with 45,X and Y chromosome mosaicism.

Child↗
PubMed1987

45,X/46,XY mosaicism. A clinical review and report of ten cases.

The clinical findings in ten patients with 45,X/46,XY mosaicism are described. Three girls presented with short stature, delayed sexual development or Turner-like stigmata without signs of virilization. Bilaterally gonadoblastomas were found in two girls, and the gonads in one of these girls also contained mucinous cystadenomas. The remaining seven patients were raised as boys. Three had scrotal hypospadias and mixed gonadal dysgenesis. Three presented as male pseudohermaphrodites with scrotal or penoscrotal hypospadias and bilateral testes. One male was diagnosed in adulthood because of gynecomastia, but had normal male external genitals. The clinical findings illustrate the wide spectrum of phenotypic manifestations of 45,X/46,XY mosaicism, ranging from females with Turner-like phenotypes, phenotypic males and females with mixed gonadal dysgenesis, male pseudohermaphroditism to almost phenotypic normal males.

Adolescent↗
PubMed1987

Elevated 1,25-dihydroxyvitamin D and normocalcaemia in presumed familial Williams syndrome.

Two brothers with Williams syndrome without hypercalcaemia are presented. One boy died during the first month of life. His brother also had the typical phenotypic features of the elfin facies. He developed severe microcephaly and cataract and died at the age of 9 years. The skeleton was osteosclerotic at birth, and became generally osteoporotic at the age of 2 years. He had persistently elevated 1,25-dihydroxyvitamin D levels during the first 2 years of life, in spite of normocalcaemia. At autopsy, microcalcifications were found in the brain and kidneys. The present report underscores the familial occurrence of Williams syndrome of severe degree. Elevated 1,25-dihydroxyvitamin D levels without hypercalcaemia have not been reported previously, and may suggest causal heterogeneity of the Williams syndrome.

Brain↗
PubMed1987

Growth hormone therapy in short stature.

Unlimited availability of growth hormone (GH), and the demonstration of increased growth velocity (GV) during GH treatment in non-GH-deficient children have suggested new indications for GH therapy in short stature. There are two principle conditions with GH-related short stature: classical growth hormone deficiency (CGHD) and growth hormone neurosecretory dysfunction (GHND). Present knowledge about the effects of GH treatment in these and other disorders of short stature are reviewed. In non-CGHD, it is not possible to predict the short-term effect on growth during GH therapy, and even if GV increases, the effect on final adult height remains to be documented. This, together with potential side effects and the high expense of GH treatment, exhort to a restricted attitude towards routine GH treatment of short children without GH deficiency.

Adolescent↗
PubMed1987

Growth hormone deficiency associated with the ectrodactyly-ectodermal dysplasia-clefting syndrome and isolated absent septum pellucidum.

Two growth hormone-deficient patients with particular developmental defects are presented. One patient had the ectrodactyly-ectodermal dysplasia-clefting syndrome with lobster-claw deformities of the hands; thin, blond, and dry hair and enamel hypoplasia; and a facial raphe on the right side of the philtrum. The other patient had isolated absence of the septum pellucidum. The facial raphe and the absent septum pellucidum are related to cleft lip and septooptic dysplasia, conditions that have been associated with growth hormone failure. The association of the ectrodactyly-ectodermal dysplasia-clefting syndrome with isolated growth hormone deficiency has not been described previously.

Abnormalities, Multiple↗