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Biomedical subjects

H Petersen

Publications and source records attributed to H Petersen.

At least 163 records · Page 9Linked to original sources
PubMed1977

Solubility profiles and thermodynamics of parabens in aliphatic alcohols.

The solubility of a series of compounds was determined in a wide polarity spectrum of normal aliphatic alcohols over a limited temperature range. The solutes chosen were the methyl through n-butyl p-hydroxybenzoates, several of these being useful preservatives. Solubility profiles were determined for these compounds, and the effect of temperature upon their solubility behavior was investigated. The solubility of the solutes is expressed in several concentration notations; mole fraction plots showed a variable twin peak array as a function of the dielectric constant for the solutes studied. Since heats of fusion were available and data were generated as a function of temperature, thermodynamic parameters for these systems could be calculated. The relationship of these parameters to multiple solubility peak array is discussed.

Alcohols↗
PubMed1977

ECG recording in emergency home visits.

During the first half of 1974, 756 emergency home calls have been made by 6 doctors in the City of Oslo. A portable ECG instrument was available at all visits. The visits were unselected as regards complaints. ECG was recorded in 7% of all patients and in 19% of all patients over 60 years of age. The main indication for recording an ECG was chest pain (nearly 2/3 of all recordings). In only a small number of cases did the recording give a definite result as regards diagnosis of management of the case. However, a slight additional benefit was obtained with a majority of the ECG recordings, including what we defined as a phychotherapeutic benefit. The results of this study indicate that the value of a portable electrocardiograph is very limited for emergency home calls in a city.

Adolescent↗
PubMed1977

Pattern of acute drug poisoning in Oslo.

All 1742 admissions occasioned by acute drug poisoning to a medical ward in Oslo during the periods 1958--60, 1963--65, 1966--69 and 1970--73 have been reviewed. The number of admissions per annum in these periods was 99, 119, 128 and 144, respectively. Because the hospital situation and number of inhabitants in the city remained fairly constant from 1958 to 1973, the increasing figures were assumed to reflect a corresponding increase in the incidence of acute drug poisoning in Oslo. The incidence was estimated to be within the range of 1--2 per 1000 inhabitants per annum. No female predominance was noted except for the age group under 30 years. The occurrence of barbiturate poisonings decreased markedly during the peroids studied, whereas those due to non-barbiturate hypnotics, tranquillizers and tricyclic antidepressants showed a proportionate increase. Slightly less than one fourth of the females and half of the males had taken alcohol. More males (43%) than females (13%) also were alcoholics. A suicidal intention was, however, found more frequently among females (70%) than males (43%). The hospital mortality was approximately 1 %. No death was associated with tricyclic antidepressants, which in the last study period had been ingested by approximately 10% of all patients.

Adult↗
PubMed1977

Biomedical survey in North Samar Province, Philippine Islands.

A biomedical survey was carried out in North Samar Province, Philipines to update information on the prevalence of parasitic and other infectious diseases. A total of 1,394 stool specimens, 1,859 blood smears and 1,274 sera were collected from persons living in 8 barrios. Stools were examined for intestinal parasites, bloods smears for malaria and filariasis and sera tested for antibodies to Schistosoma japonicum, Entamoeba histolytica, Toxoplasma gondii, influenza A and B, and Japanese encephalitis virus. The prevalence rates for intestinal parasites were: Trichuris trichiura 90%, Ascaris lumbricoides 78%, hookworm 65%, Schistosoma japonicum 15%, Strongyloides stercoralis 1%, Entamoeba coli 16%, Endolimax nana 6%, entamoeba histolytica 5%, Giardia lamblia 3%, Entaemoeba hartmanii 1%, Chilomastix mesnili 1%. No malaria was found but microfilariae of Wuchereria bancrofti were detected in 4% of the blood smears; the MfD50 was 12.9. The circumoval precipitin test (COPT) was used to detect antibodies to Schistosoma japonicum and 65% of 994 sera was considered positive. The indirect hemagglutination test (IHA) was used for detecting antibodies to Entamoeba histolytica and Toxoplasma gondii and 5% and 3% of 1,274 sera tested were positive at titers equal to or greater than 1:128 and 1:256, respectively. Hemagglutination inhibition tests (HI) were used to detect antibodies to Influenza A2HK68, Influenza A2HK68, Influenza B2T62 and Japanese encephalitis virus and 72%, 12% and 78%, respectively, of 1201 sera were considered positive at titers equal to or greater than 1:20.

Adolescent↗
PubMed1976

Solubility of straight-chain and branched alkyl barbiturates in straight-chain alcohols.

The solubilities of a series of chemically related barbiturates, including some medically useful ones as well as phenobarbital, were determined at 25 degrees in the straight-chain alcohols methanol through butanol. The solubility values are given in both milligrams per milliliter and the mole fraction notation. The solubility in methanol was the highest and decreased nonlinearly for the solubility in 1-butanol. In several cases, mole fraction solubility gave shouldering or peaking as a function of the carbon number of the solvent. This series of barbiturates was broken down into two subsets of straight-chain and branched alkyl barbiturates, and solubility ratios in these subsets were considered.

Alcohols↗
PubMed1976

Molecular orbital calculations for parabens: a possible mechanism of action.

Molecular orbital calculations were carried out on the series benzoic acid, p-hydroxybenzoic acid, methylparaben, and ethylparaben. The characteristic trends of this entire series of preservatives are demonstrated by these members. The computer program used was Iterated Extended Hückel Theory. These systems were characterized in terms of atomic charge distributions, effect of hydroxyl and ester groups (both sterically and electronically), preferred molecular conformations, and distinguishing features of molecular orbitals. Through this approach, it was hoped that a common mode of action for all members of this series could be detected and that the trend(s) in this feature would correlate with known trends in activity of members of this series.

Chemical Phenomena↗
PubMed1976

Altered pancreatic function after proximal gastric vagotomy in man.

The secretion of bicarbonate into the duodenum in response to stepwise increasing doses of secretin (0.078, 0.23, 0.7, and 2.1 U/kg-hr) was investigated in 11 duodenal ulcer patients before and about 1 1/2 years after proximal gastric vagotomy. After the vagotomy the mean output of bicarbonate in response to the two lowest doses of secretin increased from 2.2 to 3.7 mmoles per 30 min im response to 0.078 U/kg-hr and from 6.6 to 9.8 mmoles per 30 min in response to 0.23 U/kg-hr. On the other hand, the output of bicarbonate in response to the highest dose of secretin decreased from 20.3 mmoles per 30 min before to 16.5 mmoles per 30 min after the vagotomy. The dose of secretin required for half-maximal stimulation decreased from 0.7 to 0.3 U/kg-hr. The calculated maximal bicarbonate response decreased from 27.8 to 17.7 mmoles per 30 min. Thus, increased sensitivity of the bicarbonate-producing cells to low doses of secretin and decreased bicarbonate secretory capacity of the pancreas after proximal gastric vagotomy were found.

Adolescent↗
PubMed1976

[Hemodynamics, metabolism and function of the perfused pancreas under normal temperature].

The canine pancreas-duodenum has been perfused for 3 h with a membrane oxygenator, a pulsatile pump and a heat exchanger at a temperature of 37 degrees C. Among the criteria used in this study, the insulin output into the venous blood in response to glucose administration, as well as pancreas secretion after secretion stimulation were those found to be the most reliable indicators as to the viability of the pancreas. This is further supported by an average oxygen consumption of 0,77 ml O2/100 g at a constant flow of 80 ml/min and a perfusion pressure of 75 mm Hg. The pressure/flow relationship as for any other perfused organ was a safe indicator as to the viability of the perfused pancreas. The functional viability correlated with our anatomical findings.

Animals↗
PubMed1975

[Experimental surgery in pancreas/autotransplantation (author's transl)].

We have described to technique of one stage intraabdominal heterotopic pancreaticduodenal autotransplantation which has resulted in long term survival of dogs in good health. Malnutrition related to pancreatic exocrine hypofunction occurs initially but gradual recovery by 3 months nutrition is normal. In contrast, endocrine function is well preserved throughout the postoperative period except for a few days immediately after transplantation. Tolbutamide testing showed a significant prolongation of hypoglycemia as compared to controls although glucose tolerance curves were normal. There was no fibrosis after pancreas-autotransplantation. This experimental model is useful for long term evaluation of heterotopic transplantation of the pancreas. Denervation and lymphatic interruption of the pancreas may cause a transient but not definitive influence on pancreatic endocrine or exocrine function.

Animals↗
PubMed1975

[Thiamine and thiamine pyrophosphate in obsese patients during partial and total fasting (author's transl)].

The development of vitamin B1 (thiamine) deficiency was investigated in 17 obese patients in the course of a 1000 calory diet or during total fasting for a fortnight. Compared with normal persons no changes of concentrations of total thiamine, TPP, and pyruvate in the blood; thiamine excretion in the urine, or activiation coefficient of the eryhrocyte transketolase (alphaETK) were observed during the reducing diet. However, during a fortnight's total fasting all values decreased significantly to those of thiamine deficiency. The thiamine pyrophosphate (TPP) levels in the blood dropped from the 1st to the 14th day, whereas the alphaETK rose accordingly and the pyruvate levels showed a delayed rise. Total thiamine content of the blood and thiamine excretion in the urine only showed significantly different values when comparing the 1st and the 14th day. There was no dependency of thiamine excretion on urinary output. Clinical symptoms of thiamine deficiency could be demonstrated in no case.

Diet, Reducing↗
PubMed1975

Pentagastrin dose-response in peptic ulcer disease.

Stepwise increasing doses of pentagastrin (0.166, 1, and 6 mug/kg-hr) were given to 21 healthy volunteers (HV), 22 patients without peptic ulcer disease (MI), and 22, 18, and 19 patients with duodenal (DU), pyloric (PU), and gastric ulcer (GU) respectively. Maximal response (Vmax) and half maximal dose of pentagastrin (Km) were calculated for both acid and pepsin. The ability to secrete acid and pepsin was in PU and GU slightly higher and lower, respectively, than in the non-ulcer groups. Markedly elevated values were found in DU, and the pepsin secretion was relatively more increased than that of acid. The values for Km suggested a different behavior of the chief cells and the parietal cells in DU. Whereas the sensitivity of the parietal cells appeared to be abnormally high, that of the chief cells tended to be lower than normal. The discrimination between DU and the non-ulcer groups was better by estimation of pepsin than of acid secretion and tended to improve with increasing stimulation. Superiority was however, found for a submaximal dose of pentagastrin for acid secretion. No superiority in discrimination between groups was found for Vmax. Km was poorly reproducible for acid and pepsin and showed little diagnostic significance. The study suggests that pentagastrin dose-response does not provide more diagnostic information than a single dose (1 mug/kg-hr), which is maximal for pepsin and submaximal for acid.

Adolescent↗
PubMed1975

Fasting serum gastrin and basal gastric acid secretion.

The gastric secretion of acid was examined 30 minutes basally (BAO) and in response to stepwise increasing doses of pentagastrin in subjects with (n = 51) and without (n = 40) peptic ulcer disease. None of them showed basal anacidity. Before insertion of the gastric tube, blood was taken for radioimmunological determination of the serum gastrin concentration (SG). A significant positive correlation was found between SG and BAO in the subjects without ulcer. This was mainly due to a close correlation in 20 healthy young volunteers. When BAO and SG was expressed as proportions of calculated maximal acid response (Vmax) and half maximal dose of pentagastrin (Km), respectively, the positive correlation between SG and BAO was improved and reached significance also in the individuals with peptic ulcer disease. The findings suggest that the serum concentration of gastrin plays a role in the basal gastric secretion.

Duodenal Ulcer↗