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Biomedical subjects

P Hoffmann

Publications and source records attributed to P Hoffmann.

315 records · Page 18Linked to original sources
PubMedDate not supplied

Influence of dietary linoleic acid on cardiac function and prostaglandin release and on the effects of isoprenaline in the isolated rat heart.

We studied the effects of dietary linoleate on cardiac function and on the effectiveness of isoprenaline in isolated rat heart preparations. Male Wistar rats were fed either a diet rich in linoleic acid (LA) (25% of digestible energy as sunflower oil, 5% lard) or an LA-deficient diet (30% hydrogenated palm kernel oil). Control rats received a standard lab chow. Under certain experimental conditions the LA-rich diet resulted in increased contractile force, coronary flow rate, and prostaglandin (PG) release (PG-like substances and PGI2) and in a reduction in heart rate. These effects were modified by the duration of the feeding period and/or the age of the animals. In isolated perfused hearts of rats fed on a diet rich in LA for a 10-week period the inotropic effects of isoprenaline were diminished, whereas the isoprenaline-induced increase in coronary flow rate was augmented. The PG-releasing effect of isoprenaline was antagonized by the LA-rich diet. Preliminary in vivo investigations support these in vitro results. The mechanisms by which dietary LA influences cardiac function and the effectiveness of isoprenaline remain unclear.

Animal Feed↗
PubMedDate not supplied

Impaired catecholamine inactivation. A prohypertensive stimulus after dietary linoleate deficiency in salt-loaded rats?

Experiments were carried out on salt-loaded rats (1.5% NaCl as drinking fluid) to further explore the mechanisms by which blood pressure increases after a linoleic acid-deficient (LAd) diet. In 4-week-old LAd rats (0.5 cal% LA, hydrogenated palm kernel fat) compared to linoleic acid-rich rats (LAr, 13.3 cal% LA, sunflower oil), we observed, from the base of a reduced content of omega-6-polyunsaturated fatty acids in the tissues, an increase in blood pressure by 12 mm Hg (p less than 0.001), a diminished formation of prostaglandin E (PGE), and an unchanged formation of PGF in the aorta as well as a reduction in the in vitro uptake of 14C-norepinephrine into cardiac, aortic, and renal tissues, and a reduced degradation rate of 14C-norepinephrine in cardiac tissue. These differences in LAr vs LAd rats were not exaggerated. With respect to aortic PGE formation, 14C-norepinephrine uptake into aortic and renal tissues and 14C-norepinephrine degradation even lessened when the diet was begun prenatally, although the reduction of omega 6-polyunsaturated fatty acids in the tissues was aggravated. Our conclusion is that a fault in catecholamine inactivation may be involved in the pathogenesis of increased sympathetic activity and blood pressure elevation in LAd-fed, salt-loaded rats, possibly via alterations of endogenous prostanoid formation.

Animals↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: I. Studies on the acute oral toxicity of a complex mixture of waste products from the aluminium plasma etching process.

In dry etching processes--one of the sources of potential exposure to toxic wastes in the semiconductor industry--complex mixtures of inorganic and organic compounds arise from reactions between feed stock gases (BCl3/Cl2), top layers (aluminium photoresist), and the carrier gas (N2). Two different fractions of the complex mixture--one an ethanolic solution (ES) and the other an insoluble liquid residue (LR)--were examined for acute oral toxicity in rats. Analytical data showed that the ethanol soluble fraction contained mainly inorganic compounds, whereas the residue contained various halogenated hydrocarbons. Neither death nor behavioral changes occurred after oral administration and observation up to 23 days. ES caused a lower mean arterial blood pressure in both sexes, increased P-R-intervals in male rats, and caused some mild biochemical and hematological alterations and changes in relative organ weights compared to the control groups. Exposure to LR influenced food and water intake, and caused a significant decrease in body weights, signs of polyurie, as well as changes in various relative organ weights and biochemical and hematological parameters. The blood pressure of the male animals fell and the heart rates of both sexes decreased.

Aluminum↗
PubMedDate not supplied

Visible spectrophotometric determination of tantalum in soil, sediment, minerals, and alloys.

A new, sensitive, and selective method is described for the spectrophotometric determination of Ta(V). The method is based on the extraction of the Ta(V)-F-CV+ complex (CV+ = crystal violet cation) with a benzene solution of imidoyl derivatives (ID), i.e., N,N'-diphenylbenzamidine (DPBA), N-hydroxy-N,N'-diphenylbenzamidine, and N-(2,5-dimethyl)phenyl-p-tolylimidoylphenylhydrazine, from sulfuric acid solution; DPBA was selected for detailed study. The molar absorptivities of the Ta(V)-F-CV+-ID complexes in the benzene solution were in the range of (1.00-1.65) x 10(5) L/mol x cm at 600 nm. The limit of detection was 7 ng Ta/mL (which had an absorbance greater than that of the blank + 3 standard deviations). The optimization of the analytical variables, the composition of the complex, and the effect of diverse ions in the determination of Ta are discussed. The present method was applied to the determination of Ta in environmental samples, i.e., soil, sediment, minerals, and alloys.

Acids↗
PubMedDate not supplied

Delayed cutaneous hypersensitivity after multiple injury and severe burn.

LetHality and overall prognosis after multiple injury and severe burn are determined to a major degree by the incidence and severity of infectious complications. Immunological reactions are influenced by the extent of trauma. Multitest Mérieux is an appropriate and an easily applicable means to delayed hypersensitivity testing (DHT). This study investigates to what extent Multitest Mérieux can help to predict the prognosis of multiply injured and severely burnt patients and whether new therapeutic measures can be recommended. This study encloses 52 patients during 1985: 16 severe burns, 20 multiple injuries with craniocerebral trauma and 16 without. Beginning with the day of injury standard laboratory and cardiopulmonary parameters were recorded every 48 hours. Delayed hypersensitivity testing was performed using Multitest Mérieux. The extent of trauma was determined by help of the ISS. All quantitative laboratory and cardiopulmonary parameters showed no significant changes in correlation to the clinical course during the period under investigation. However, a significant correlation between Multitest reaction at days six and eight and its overall results and the rate of infectious complications was found. Moreover, the extent of trauma measured by ISS shows a positive correlation with the rate of anergic reactions in Multitest. Thus Multitest Mérieux is an easily applicable and reliable means to the assessment of the prognosis after multiple injury and severe burn. Therapeutical recommendations beyond today's intensive care concepts cannot be given.

Brain Injuries↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: II. Studies on the subacute inhalation toxicity and genotoxicity of gaseous waste products from the aluminum plasma etching process.

Male and female Wistar rats were exposed to waste gas arising from a plasma etching process in the semiconductor industries for six hr per day, five days per week, for four weeks in order to characterize subacute organ toxicity and genotoxicity. The waste gas was a complex mixture of different chlorinated hydrocarbons, inorganic by-products, and unused process gases, diluted by room air. Neither death nor behavioral changes occurred after subacute exposure. No significant exposure-related effects on body weight gain, hematology, or cardiovascular parameters were observed. Only slight effects on organ weights and clinical chemistry were seen in the exposed animals. The exposed rats of both sexes showed statistically significant increases in chromosomal aberrations and sister chromatid exchanges in bone marrow cells.

Administration, Inhalation↗
PubMedDate not supplied

[The role of endoscopy in the diagnosis and treatment of keratinizing and desquamating malpighian metaplasia of the kidney pelvis].

Keratinized squamous cell metaplasia of the renal pelvis (KSMRP) is a rare lesion, difficult to differentiate from urothelial tumour on the basis of the usual morphological examinations. It is therefore usually diagnosed retrospectively, on histological examination of a nephroureterectomy specimen. However, as its benign nature justifies conservative treatment, preoperative recognition of this lesion is essential. Upper urinary tract endoscopy, which allows diagnosis and treatment of this disease, is therefore very important in this context. Endoscopy is indicated when KSMRP is suspected clinically in a doubtful case of urothelial tumour of the upper urinary tract, in a context of passage of soft stones or a history of renal stones or upper urinary tract infection. Ureteroscopy constitutes the first step to confirm the diagnosis. It must be completed by a percutaneous procedure to eradicate any residual lesion, which could be responsible for recurrence. We report a case of KSMRP in a solitary kidney treated by retrograde and percutaneous endoscopic surgery.

Diagnosis, Differential↗