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Biomedical subjects

K Iversen

Publications and source records attributed to K Iversen.

At least 37 records · Page 2Linked to original sources
PubMed1995

Myocardial oxygen extraction ratio is decreased during endotoxemia in pigs.

Why the myocardial oxygen extraction ratio (ERm) is decreased during septic shock in humans is unknown. Therefore, we calculated ERm in 15 anesthetized pigs by measuring arterial and coronary venous oxygen content. We measured myocardial lactate flux, myocardial contractility, and global myocardial blood flow and its distribution. After baseline measurements, animals received either saline (n = 6) or 50 micrograms/kg of endotoxin (n = 9). Measurements were repeated for 4 h. After endotoxin, ERm decreased from 67 +/- 12% at baseline to 36 +/- 10% (P < 0.01) at 1 h and 54 +/- 10% (P < 0.05) at 4 h, associated with an increased myocardial blood flow that was heterogeneous. Neither myocardial oxygen nor lactate consumption decreased in the endotoxin group, and changes in left ventricular contractility were not correlated with changes in ERm. We conclude that the decrease in ERm after endotoxin infusion is due to both increased blood flow and mismatching between myocardial oxygen delivery and demand. Impaired myocardial oxygen extraction capacity during sepsis did not cause global myocardial tissue hypoxia.

Animals↗
PubMed1985

Gammahydroxybutyric acid: central biochemical and behavioral effects in neonatal rats.

Administration of gammahydroxybutyric acid (GHBA) to 4 days old animals caused a dose dependent decrease in locomotor activity. GHBA also induced a marked hypoventilation, irregular breathing and finally apnea, while heart rate was slightly increased. Changes in monoamine neurotransmitter turnover indicated an inhibition of dopamine (DA) neurotransmission. It is concluded that GHBA mechanisms in the neonatal rat brain are biochemically as well as functionally mature at an early age and that the effects on locomotor activity and respiratory regulation at least partly may involve interactions with central DA neurotransmission.

Animals↗
PubMed1984

Central GABA mechanisms during postnatal development in the rat: neurochemical characteristics.

Various biochemical characteristics of the developing GABA system was studied in rats from 1 to 60 days of age. Endogenous GABA concentrations were high in the limbic system, midbrain, brain stem and spinal cord at birth. Until 7 days of postnatal age, GABA concentrations generally decreased, thereafter an increase was seen and at 60 days of age the GABA concentrations exceeded those found in the neonate except for the spinal cord regions. After GABA-T inhibition with AOAA, GABA concentrations increased in all brain regions, however considerably more marked in the 28 days old rats compared to the 4 days old animals. Turnover rate of GABA was estimated by investigating the rate of disappearance of GABA after GAD inhibition with 3-MPA. Calculated turnover time of whole brain GABA was 34.1 min in the 4 days old rats and 19.9 min in the 28 days old animals. The results from this investigation clearly indicate a caudal to rostral maturational gradient in the development of endogenous GABA concentrations as well as synthesis capacity. Furthermore, turnover rate of total whole brain GABA but probably not of GABA in the neuronal pool is retarded in the 4 days old rats compared to the adolescent animals.

3-Mercaptopropionic Acid↗
PubMed1983

Effects of GABA and some GABA analogues on respiratory regulation in the preterm rabbit.

Preterm neonatal rabbits (gestational age 29 days) were given GABA (750 mg/kg) or the GABA-like drugs muscimol (2 mg/kg) and GHBA (375 mg/kg) intraperitoneally. Basal respiration and the ventilatory response to 10% CO2 were studied, before and after drug administration, in a whole body plethysmograph during halothane anesthesia. The three drugs tested all caused a decrease in minute volume. The decrease in minute volume was mainly due to a decrease in tidal volume after GABA and muscimol, while GHBA reduced minute volume due to a decrease in respiratory frequency. A decrease in respiratory frequency was also seen after muscimol administration. Changes in the respiratory time intervals were seen after muscimol and GHBA both causing significant increases in expiratory and respiratory time. 'Inspiratory drive' and 'respiratory timing mechanisms' were evaluated by VT/TI and TI/TTOT, respectively. GABA and muscimol reduced both VT/TI and TI/TTOT while GHBA only reduced TI/TTOT. Addition of 10% CO2 to the inhalation gas caused an increase in tidal volume and minute volume during control conditions. This response to CO2 was abolished by GABA and GHBA treatment. Our findings demonstrate that GABA and GABA-like drugs cause respiratory depression in the preterm neonate. Central mechanisms are most likely involved in this response. These findings may be relevant to the irregular or apneic breathing sometimes seen in the preterm human infant.

Animals↗
PubMed1982

gamma-Aminobutyric acid concentrations in the cerebrospinal fluid of newborn infants.

gamma-Aminobutyric acid (GABA) concentrations in cerebrospinal fluid (CSF) were measured in 20 neonates with various gestational and postnatal ages. These concentrations varied between 9 and 45 nmol/ml which is approximately 20-100 times the concentrations found in adults. CSF GABA concentrations tended to decrease with advancing gestational age. No apparent alterations were noted with increasing postnatal age (until 6 weeks of age). Asphyxia but not neonatal sepsis was accompanied by an increase in CSF GABA concentrations compared to respective controls.

Asphyxia Neonatorum↗
PubMed1980

Mucosal malignant melanomas.

Forty-seven cases of mucosal malignant melanomas and the recent literature are reviewed. Twenty patients had head and neck mucosal malignant melanomas; 14 had vulvar and 7 vaginal melanomas. Included are also isolated cases of urethral, anal and esophageal melanoma. Mucosal malignant melanomas are more aggressive and behave differently from cutaneous melanomas. The pathologic description and leveling system known from cutaneous melanomas are not applicable in mucosal melanomas, and other prognostic factors such as depth of invasion seem more important. Extensive surgical procedures is the favored treatment when cure is intended whereas radiation, chemotherapy and immunotherapy currently serve mainly as palliative measures. The prognosis is generally grave. In this review, 5 of the 20 patients with head and neck tumors and 3 of the patients with vulvar tumors had 5 years cures, but later recurrences are not infrequent. Two patients are alive with metastatic disease whereas the rest died from primary or recurrent disease. The main problem in head and neck tumors was gaining control over the local disease process, whereas metastatic disease was less ominous and less frequent. This was different in vulvar melanomas, in which disseminated metastatic disease made the disease difficult to control in the majority of cases. The course of the 47 patients, the poor treatment results and the rarity of the disease show the need for centralized registration and management of mucosal malignant melanomas.

Adult↗
PubMed1980

The role of acute hepatitis type A, B, and non-A non-B in the development of chronic active liver disease.

In 19 patients followed from biopsy-verified acute viral hepatitis to chronic active liver disease and 74 patients followed to complete resolution verified by a normal liver biopsy, sera from the acute phase were studied for serologic evidence of hepatitis type A and B. Eleven of the 19 patients who developed chronic active liver disease progressed from acute hepatitis type B and 7 from acute hepatitis type non-A non-B. One patient could not be classified because the sera were exhausted. None had serological markers of actual hepatitis type A infection. Of the 74 patients with a histologically complete resolution, the acute episode could be classified as type B hepatitis in 47 and type A hepatitis in 13 patients. The remaining 14 patients were classified as having acute viral hepatitis type non-A non-B. Our findings confirm that type B and non-A non-B hepatitis may give rise to chronic liver disease, whereas type A hepatitis so far has not been demonstrated to initiate a chronic liver disease.

Age Factors↗
PubMed1980

Human leucocyte antigens in patients with alcoholic liver cirrhosis.

No significant differences in the frequencies of HLA-B8, -B40, and other HLA-A, -B, and -C phenotypes were found among patients with histologically verified alcoholic cirrhosis compared with normal controls when the p values were multiplied by the number of comparisons. This was found both in the present study of 45 patients and in the combined data of this and three other similar studies. However, these findings do not rule out that alcoholic cirrhosis might be associated with HLA factors (for example. HLA-D/DR antigens) controlling immune responses.

Adult↗
PubMed1979

Effects on the child of alcohol abuse during pregnancy. Retrospective and prospective studies.

Retrospective and prospective investigations of children to alcoholic women gave an incidence of fetal alcohol lesion of one per 300 deliveries of whom half had the complete fetal alcohol syndrome. Perinatal and infant mortalities were increased seven to tenfold and low birth weight (less than or equal to 2 500 g), preterm deliveries (less than 37 weeks) and smallness for gestational age (less than -2 S.D.) were increased eightfold, threefold and twelvefold, respectively. Small size at birth correlated with reduced mental performance later in life, 58% had IQ below 85 and 19% below 70.8% had cerebral palsy. The incidence of cerebral palsy associated with maternal inebriety was 1/5 000 deliveries, i.e. every sixth case of cerebral palsy. Tracing of alcoholic women during pregnancy and treatment gave favourable effect on intrauterine growth when sobriety could be induced early in pregnancy but could not protect from functional brain disturbance measured by neurological performance and be evoked response electroencephalography. Damage to the fetus by alcohol is now the largest known health hazard by a noxious agent that is preventable.

Alcoholism↗
PubMed1975

A review of children operated upon because of stenosis of the pelvo-ureteral junction.

The authors report the late results of reconstructive surgery on stenosis of the pelvo-ureteral junction in children. 69 patients had been operated during 1965--1970. The results on clinical grounds were good: the infections and pain disappeared and the renal function was normal; however, the operation had no noticeable effect on the hydronephrosis.

Adolescent↗
PubMed1975

Acute viral hepatitis: factors possibly predicting chronic liver disease.

A number of clinical, biochemical, immunological and morphological variables were recorded at first admission of 500 consecutive patients with biopsy verified acute viral hepatitis in the period February 1969-June 1972. In February 1973, 28 of these patients had a morphologically documented chronic liver disease: 4 cirrhosis of the liver, 15 chronic aggressive hepatitis, and 9 chronic persistent hepatitis. 74 patients were followed up until morphological normalization took place. The initially recorded variables in the two groups were compared, and the following factors were significantly higher in the group with subsequent development of chronic liver disease:--frequency of drug addicts, median of the highest gammaglobulin, ANA, SMA, partial destruction of the limiting membrane, incidence of piecemeal necrosis, and pronounced plasma cell infiltration in the portal tracts. These preliminary results suggest that factors in the initial phase of acute viral hepatitis can be helpful to some extent in predicting the course and prognosis of the disease.

Acute Disease↗
PubMed1975

Acute viral hepatitis: a comparative study of clinical, biochemical, morphological and immunological features in patients with and without Australia Antigen.

500 consecutive patients with acute viral hepatitis verified by biopsy were divided into groups of 202 patients with detectable Australia (Au) antigen and 298 patients without antigenaemia at the time of admission to hospital. Comparison was made of the initially recorded clinical, biochemical, histological and serological variables in the two groups. Judged by both histological and biochemical criteria, the acute disease was more severe in the 202 patients with Au antigen than in the 298 patients without Au antigen. Evidence is presented that this difference is possibly due more to qualitative aetiological differences between the two groups than to the duration of antigenaemia or the time of hospitalization. Thus, the demonstration of Au antigenaemia provides not only epidemiological but also relevant clinical information.

Acute Disease↗