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Biomedical subjects

E Wolf

Publications and source records attributed to E Wolf.

At least 271 records · Page 15Linked to original sources
PubMed1987

Chiral separation of enantiomers of substituted alpha- and beta-alanine and gamma-aminobutyric acid analogues by gas chromatography and high-performance liquid chromatography.

Gas chromatography (GC) with a chiral stationary phase, Chirasil-Val, has been used for separation of the enantiomers of several analogues of alpha- and beta-alanine as their N-trifluoroacetyl isopropyl esters. The same chiral phase GC procedure has been applied to the enantiomeric separation of various substituted gamma-aminobutyric acid analogues (GABA). Reversed-phase high-performance liquid chromatography (HPLC) with the chiral copper-L-proline complex allowed a clear resolution of all the alpha-amino acids in their underivatized forms. It yielded somewhat smaller separation coefficients for the substituted beta-alanines and no resolution for the GABA analogues. The influence of the nature of the amino acid, alpha, beta or gamma, and the effects of the different substituents on the separation coefficients obtained by GC and HPLC are discussed.

Alanine↗
PubMed1987

A non-invasive method for measuring inspiratory muscle fatigue during progressive isocapnic hyperventilation in man.

Eleven normal adults each performed a ten minute progressive isocapnic hyperventilation (PIHV) test in which ventilatory levels were increased every two minutes. All subjects exhibited mechanical fatigue by failing to maintain the target of 80% of maximum voluntary ventilation (MVV). The mean ventilation at this level was 67.5 +/- 1.4% MVV. This fatigue was accompanied by a fall in transdiaphragmatic pressure. During the test the EMG of the sternomastoid (SM) was monitored by surface electrodes and was analyzed using fast-fourier transform. The centroid frequency (Fc) fell as ventilation increased, and correlated negatively with the inability to achieve target ventilation(r = -0.99, p less than 0.015). Five subjects performed the test while the diaphragmatic EMG was recorded from an oesophageal electrode (DIes) and from surface electrodes (DIs). The Fc of DIes fell with increasing ventilation levels (r = -0.95, p less than 0.05) and there was a correlation between the Fc changes of both DIes and the SM (r = -0.92, p less than 0.001). The Fc of DIs did not correlate with either mechanical performance or the Fc of DIes, because of contamination of surface signals by signals from expiratory muscles. It is concluded that the PIHV along with surface monitoring of EMG activity from the sternomastoid can serve as a non-invasive method for evaluating inspiratory muscle fatigue.

Adult↗
PubMed1987

Resolution of the enantiomers of various alpha-substituted ornithine and lysine analogs by high-performance liquid chromatography with chiral eluant and by gas chromatography on Chirasil-Val.

A reversed-phase high-performance liquid chromatography method, with L-proline and copper as chiral mobile phase, is described for the enantiomeric resolution of various alpha-substituted ornithine and lysine analogs. Although ornithine gives no separation with the chiral eluant used, excellent resolutions are obtained for various alpha-alkyl-, alpha-halogenomethyl-, alpha-vinyl-, and alpha-ethynyl-substituted ornithines. Similar separations are also observed for the dehydroornithine and lysine analogs. Gas chromatography on a chiral stationary phase, Chirasil-Val, allows the resolution of the ornithine and lysine analogs after derivatization into the monofluoroacyl derivatives of their corresponding lactams. No resolution or only a poor resolution is obtained by GC on Chirasil-Val for the dehydroornithine analogs as their di-N-perfluoroacyl alkyl esters. The chiral eluant HPLC procedure is easily scaled up for the semipreparative resolution of several ornithine analogs, i.e., alpha-fluoromethylornithine, alpha-difluoromethylornithine, alpha-chlorofluoromethylornithine, and alpha-fluoromethyldehydroornithine, which are known as potent ornithine decarboxylase inhibitors in vitro and in vivo.

Chromatography, Gas↗
PubMed1987

Sequels to screening for hypertension and diabetes mellitus in Fiji.

We evaluated the outcome of a case-finding programme resulting from an epidemiological survey on diabetes and cardiovascular risk factors by re-interviewing 318 persons who had been found to have hypertension and/or diabetes mellitus in a population survey carried out in Fiji 1.5 years earlier in 1980. At re-examination, 34% of the hypertensive patients and 43% of the diabetic patients were not aware of their diagnosis. However, the proportion of treated hypertensive people was tripled and that of diabetic patients doubled. It was not possible to identify the characteristics of the persons who were missed in the follow-up. Many persons who were unaware of their condition regularly used, however, the existing health services available. On the other hand, several initially treated cases had no proper follow-up. More careful planning and development of comprehensive community-based programmes for hypertension and diabetes are needed in Fiji. Simple population screening for hypertension and diabetes may result in an extra work load and limit the available health care resources so that the overall outcome is not satisfactory.

Adult↗
PubMed1987

Dissociation of the natriuretic and antikaliuretic properties of triamterene derivatives by dose-response experiments.

Several derivatives of triamterene were synthesized with the aim of obtaining physicochemical properties superior to those of triamterene. Their effects on electrolyte excretion were tested with dose-response curves in rats: a dissociation of ED50 values of Na+ excretion from those of K+ retention was found; while the ED50 values of natriuresis were structure independent, the ED50 values for potassium retention depended highly on the charge of the side chain of triamterene derivatives. Acidic compounds displayed low and amines high K+-retaining potencies. Hence we postulate that there are at least two sites of action of the tested compounds in the kidney. (i) The first is the Na+ difference; this is the main driving force for K+ secretion. The affinity to the Na+ conductance is not correlated with the basic/acidic properties of the compounds. (ii) The second site is the finite K+ conductance of the luminal membrane of the distal tubule. The affinity of the drugs to this K+ conductance depends strongly on the charge of the molecule. Only pteridine derivatives with a basic side chain, i.e., with a high pKa value, block the membrane K+ conductance and are therefore potent potassium-retaining drugs.

Animals↗
PubMed1987

Familial bilateral paralysis of diaphragm. Adult onset.

At age 50 two homozygote twin brothers developed bilateral paralysis of the diaphragm. No infectious, metabolic, degenerative or proliferative disorders of the neuromuscular system and no thoracic diseases which could explain this lesion were detected during four years of follow-up. It appears thus to be an isolated lesion of genetic origin. To the best of our knowledge, no similar cases have been reported in literature.

Diaphragm↗
PubMed1987

[Intensified conventional insulin therapy in children and adolescents with type I diabetes].

Children and adolescents with type-I-diabetes are examined with regard to the influence of Intensified Conventional Insulin Therapy (ICT) on metabolic control, insulin requirement and weight development. On average the period of treatment with ICT lasted 10 months (SD: 3 months). The average insulin requirement under ICT slightly increased from 0.82 to 0.87 I.U./kg BW. The need for longer acting insulin decreased from 0.5 to 0.35 I.U./kg BW. Snacks were not necessary. On average the insulin-BE quotient increased to 2.4 I.U./BE in the morning, 1.9.I.U./BE at lunch time and 2.1 I.U./BE at night. Compared to a group being treated with Conventional Insulin Therapy the quality of metabolic control improved. Within the ICT group the part of well controlled patients rose from 10 to 30% whereas the part of poorly controlled patients decreased from 30 to 10%. Provided that Continuous subcutaneous insulin infusion pumps (CSII) cannot be applied, ICT represents the best form of therapy for well educated and highly motivated diabetics aged 12 years old or more.

Adolescent↗
PubMed1987

Trends in stroke and stomach cancer in Austria compared to selected Eastern and Western European countries.

The age-adjusted rates of stomach cancer in men and women aged 45-74 years tended to decrease in different countries in Europe between 3.0% and 5.3% per year over the last 10-15 years. East European countries had generally higher stomach cancer death rates than West European countries, and of these Austria and Finland had the highest rates. Stroke mortality decreased in West European countries in a similar way; the underlying factor might be salt intake. Between and also within West European countries a positive association has been found between changes in salt intake and trends in both stomach cancer and stroke mortality. In most East European countries, stroke mortality has increased. The greatest annual increases were in Poland and Czechoslovakia ranging between 2.9% and 4.8%. Thus, although the decline in stomach cancer mortality in Europe suggests a general reduction of salt intake, this alone was not sufficient to result in a decline in stroke mortality in East European countries. The stroke-salt intake association in East European countries might have been modified by other factors such as increased fat intake and obesity causing high blood pressure. Further studies are therefore needed to clarify the role of salt intake as a linking factor of stomach cancer and stroke.

Aged↗
PubMed1986

Prevalence of diabetes mellitus in elderly men aged 65 to 84 years in eastern and western Finland.

We studied the prevalence of diabetes mellitus in men aged 65 to 84 years in Finland. The study sample consisted of 763 men, the survivors of the Finnish cohort of the "Seven Countries Study" first examined in 1959. The participation rate in the present survey was 94%. Blood glucose, fasting and 2 h after a 75-g oral glucose load, was determined from capillary blood. Current WHO criteria for diabetes mellitus were used. The mean fasting blood glucose level, adjusted for age and body mass index, was higher in east than west Finland. It rose with age in both areas. The prevalence of diabetes was 38% in the east and 36% in west Finland. About one-third of the men had impaired glucose tolerance. In the age group 75 to 79 years, the prevalence of diabetes was 65% in the east and 50% in the west. No systematic variation in the prevalence of impaired glucose tolerance with age was found. The mean levels of body mass index decreased with age in the same way in men with diabetes, impaired glucose tolerance and normal glucose tolerance. Body mass index was not higher in men with diabetes or impaired glucose tolerance than in men with normal glucose tolerance.

Aged↗
PubMed1986

[Morphometric studies on numerical area density of glomerular cells (nuclear section) in the pathogenetic evaluation of minimal glomerular abnormalities].

Minor glomerular abnormalities (MGA) with hypercellularity (according to the WHO-nomenclature) are one of the most frequent glomerular lesions. Minimal proliferative changes in the glomerular structure can be proven only with the aid of morphometric methods. Morphometric glomerular studies were carried out in MGA with hypercellularity and with rare or minor deposits of immunoglobulins and/or complement (C3) or without deposits. Clinical symptomatology was variable (minimal to mild proteinuria, massive proteinuria, haematuria or haematuria with proteinuria). The groups examined were divided as follows: MGA without deposits and with minimal (mild) proteinuria. MGA with minor deposits and with minimal (mild) proteinuria. These two groups were statistically compared with: normal glomerular structure (after Wehner 1974); MGA with massive proteinuria or nephrotic syndrome (includes the minimal changes with nephrotic syndrome), which showed minor deposits of complement; diffuse mesangial proliferative glomerulonephritis (IgA-nephritis). The glomerular cell density, i.e. the total number of glomerular cells, averaged 3.48 cells/1,000 micron 2 in the first group and 4.26 cells/1,000 micron 2 in the second group. In normal renal corpuscles the average was 2.30 cells/1,000 micron 2. The first group has an average of 51% and the second group has an average of 84% higher cell density than normal renal corpuscles. The cell density in diffuse mesangial proliferative glomerulonephritis (IgA-nephritis) is increased by 160% compared with the norm. The first group was not statistically different in cell density from MGA with high proteinuria. We conclude, that MGA with hypercellularity and minimal to mild proteinuria represents a minimal mesangial proliferative glomerulonephritis.

Adolescent↗
PubMed1986

[Quantitative pathomorphological findings in chronic glomerulonephritis at autopsy: characterization of the grade of renal insufficiency for correlation studies].

The investigation is based on 49 autopsies at which chronic glomerulonephritis (GN) was found. The glomerular findings were classified by the WHO classification of renal diseases. The ratio of kidney weight (g) to body height (cm) gave a constitutional kidney index which correlated with the degree of global and segmental (more than 50%) sclerosis of glomeruli in chronic GN (diffuse intracapillary type). The negative correlative coefficient from simple linear regression was rho = -0.606. Chronic GN was then further subdivided into four groups which mutually correlate: diffuse sclerosing GN (so-called end-stage kidney). Index: 0.27 g/cm; diffuse sclerosing GN (over 80% glomerular sclerosis). Index: 0.49 g/cm; diffuse proliferative and extensive sclerosing GN (more than 50% and less than 80% sclerosis) Index: 0.59 g/cm; diffuse proliferative and mild to moderate sclerosing GN (less than 50% sclerosing). Index: 0.93 g/cm. The indices of the diffuse extracapillary GN were high in comparison with diffuse intracapillary GN. The kidney index of diffuse extracapillary proliferative and extensive sclerosing GN with over 80% fibrous crescents was 0.78 g/cm. Index of diffuse extracapillary proliferative and mild to moderate sclerosing GN, mostly epithelial and fibro-epithelial, few fibrous crescents was 1.30 g/cm. The mean values of the indices for normal kidneys were (males) 0.78-0.81 g/cm and (females) 0.73-0.75 g/cm (age: 20-60 years). These results may be used for correlative investigations with morphometric parameters of renal osteopathy.

Adolescent↗
PubMed1986

[Incidence and early detection of glomerulonephritis].

Within of a for the first time performed aimed study of the early recognition and frequency of the glomerulonephritis in 1,425 males the findings of an "asymptomatic proteinuria" were proved in 5.26% of the affected persons. As a result of a comprehensive investigation, the close of which was in every case the biopsy of the kidney with the histological examination of the renipuncture cylinder, a frequency of glomerulonephritis of 2.8% was found. Within this investigation the findings of an "asymptomatic proteinuria" proved to be the decisive parameter independent of the size of excretion and the reproducibility. The serological investigations did not show any specifity and proved to be insignificant for the early recognition. The results confirm that the diagnosis of "physiological proteinuria" may be made only then when there is an inconspicuous histological finding. In lacking renal histology every form of the proteinuria should at first be attributed to glomerular process.

Biopsy, Needle↗