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Biomedical subjects

S Ritz

Publications and source records attributed to S Ritz.

At least 19 recordsLinked to original sources
PubMed2000

Identification of two subtypes of infantile acid maltase deficiency.

Infantile patients with acid maltase deficiency have severe hypertrophic cardiomyopathy, left ventricular outflow obstruction, and generalized muscle weakness and die before 1 year of age. We identified 12 infants with acid maltase deficiency who had a similar clinical presentation but less severe cardiomyopathy and absence of left ventricular outflow obstruction, and 9 of 12 had longer survival with assisted ventilation and supplemental intubation.

Age of Onset↗
PubMed1996

Identification of osteocalcin as a permanent aging constituent of the bone matrix: basis for an accurate age at death determination.

Age at death determination based on aspartic acid racemization in dentin has been applied successfully in forensic odontology for several years now. An age-dependent accumulation of D-aspartic acid has also recently been demonstrated in bone osteocalcin, one of the most abundant noncollagenous proteins of the organic bone matrix. Evaluation of these initial data on in vivo racemization of aspartic acid in bone osteocalcin was taken a step further. After purification of osteocalcin from 53 skull bone specimens, the extent of aspartic acid racemization in this peptide was determined. The D-aspartic acid content of purified bone osteocalcin exhibited a very close relationship to age at death. This confirmed identification of bone osteocalcin as a permanent, 'aging' peptide of the organic bone matrix. Its D-aspartic acid content may be used as a measure of its age and hence that of the entire organism. The new biochemical approach to determination of age at death by analyzing bone is complex and demanding from a methodologic point of view, but appears to be superior in precision and reproducibility to most other methods applicable to bone.

Adult↗
PubMed1996

Postmortem diagnosis of diabetic metabolic derangement: elevated alpha 1-antitrypsin and haptoglobin glycosylation levels as an index of antemortem hyperglycemia.

Fatal diabetic metabolic derangement is difficult to diagnose postmortem because of the paucity of characteristic morphologic findings. Hyperglycemia is an indicator of diabetic derangement. Conventional biochemical parameters for postmortem diagnosis of antemortem hyperglycemic states are not sufficiently resistant to antemortem and postmortem non-diabetic influences or are suited only for long and medium-term assessment of diabetes control. In the search for other, more reliable, indices of immediately antemortem blood glucose levels, we investigated the value of glycosylation levels of serum proteins with very brief biologic half-lives: a) In vitro studies were performed on the glycosylation course of the short-lived serum proteins alpha 1-antitrypsin (alpha 1-AT) and haptoglobin (HP). b) Glycosylation levels were measured after purification of alpha 1-AT and HP from sera of living and deceased non-diabetics and diabetics. c) The resistance of alpha 1-AT and HP glycosylation levels to autolysis was investigated. Our studies revealed the following: 1) alpha 1-AT and HP glycosylate considerably more rapidly than either albumin or hemoglobin. This rapid glycosylation, combined with the rapid turnover of both proteins; facilitates detection of short-term changes in glycemia. 2) alpha 1-AT and HP glycosylation levels are autolysis-stable and can be assessed even after advanced hemolysis. 3) alpha 1-AT and HP glycosylation levels appear to allow reliable ante- and postmortem discrimination between normoglycemic and hyperglycemic metabolic states. As a tool in the postmortem diagnosis of antemortem hyperglycemic states, alpha 1-AT and HP glycosylation levels combine the advantages of a short-term parameter with resistance to non-diabetic influences.

Aged↗
PubMed1995

Age estimation in biopsy specimens of dentin.

Determination of age at death on the basis of aspartic acid racemization in dentin is one of the most reproducible and accurate methods. In Germany, age estimation by this method has so far generally not been applied to living persons, since the extraction of a tooth exclusively for age estimation when it is not medically indicated is regarded as ethically and legally problematic. The development of a biopsy technique applicable to dentin took place against this background. Testing the technique and analysis of dentinal biopsy specimens revealed that the biopsy technique is a low-risk procedure that causes only minor discomfort to the affected person. It is readily practicable and facilitates standardized specimen removal. The relationship between the extent of aspartic acid racemization in dentinal biopsy specimens and age is very close, facilitating age estimation. A prerequisite for accurate results is the performance of biopsies under strictly standardized conditions. If this is guaranteed, age determination on the basis of aspartic acid racemization in dentinal biopsy specimens appears to be superior in precision to most other methods in living persons and can be used for all age groups.

Adolescent↗
PubMed1994

Ethical, legal and medical problems on the borderline between life and death.

'Brain death' appears to be almost a closed chapter in medical history. But it remains fascinating, particularly regarding future developments, how medical discoveries, moral dilemmas, ethics and law have merged and lead to a common consent on the principal medical, ethical and juristic positions. After a consideration of these questions, topical problems concerning the extent and the limits of medical responsibilities, especially with regard to euthanasia and the problems of a broad interpretation of brain death are discussed.

Brain Death↗
PubMed1994

Estimation of age at death based on aspartic acid racemization in noncollagenous bone proteins.

Age at death determination based on the extent of aspartic acid racemization in dentin has been reported to be highly accurate and reproducible. To test the applicability of this method to human bone, aspartic acid racemization in noncollagenous proteins of bone was investigated. A close relationship was found between age at death and the extent of aspartic acid racemization in osteocalcin, the most abundant noncollagenous protein of the organic bone matrix. Our findings indicate that osteocalcin is a permanent, 'aging' constituent of the organic bone matrix whose D-aspartic acid content increases with age because of in vivo racemization. Thus, the extent of aspartic acid racemization in bone osteocalcin is a measure of the age of the peptide and hence of the entire organism. The relationship between age at death and the extent of aspartic acid racemization in purified bone osteocalcin appears to be close enough to serve as a basis for determination of age at death in forensic medicine.

Age Determination by Skeleton↗
PubMed1993

Postmortem estimation of age at death based on aspartic acid racemization in dentin: its applicability for root dentin.

The extent of aspartic acid racemization in total dentin and in dentin protein fractions from the roots of third molars was determined. In several cases coronal dentin was also investigated. The results of other authors, according to which the racemization of aspartic acid in root dentin apparently proceeds differently than in coronal dentin, could be confirmed. Consequently, the data published so far on age determination based on the extent of aspartic acid racemization in coronal dentin and the "entire dentin of longitudinal sections" cannot be applied to root dentin. In total root dentin and the acid soluble protein of root dentin, a close relationship was observed between the extent of aspartic acid racemization and age. Accordingly, estimation of age at death based on aspartic acid racemization in dentin is also possible for root dentin, apparently with good results. This is important particularly in those cases where a large portion of the coronal dentin is absent, for instance following dental treatment. In the investigation of root dentin, regression equations specific for root dentin must be employed in the estimation of age at death. Corresponding equations for third molars were calculated.

Adult↗
PubMed1993

Aspartic acid racemization in intervertebral discs as an aid to postmortem estimation of age at death.

We investigated whether measurement of aspartic acid racemization in intervertebral discs (IVD) could be used in the postmortem estimation of age at death. The extent of aspartic acid racemization in IVD tissues was found to increase with age. The rate of racemization turned out to be much higher in the nucleus pulposus than in the annulus fibrosus. The relation between age and the D-aspartic acid content in the anterior peripheral annulus fibrosus of IVD was close enough to allow postmortem estimation of age at death based on the extent of aspartic acid racemization in this tissue.

Adolescent↗
PubMed1992

Measurement of digitalis-glycoside levels in ocular tissues: a way to improve postmortem diagnosis of lethal digitalis-glycoside poisoning? I. Digoxin.

Prompted by animal studies reporting the accumulation of digitalis-glycosides in ocular tissues, we investigated whether measurement of digoxin levels in human ocular tissues can improve the postmortem diagnosis of lethal digoxin intoxication. Digoxin was measured in the vitreous humor and choroid-retina of patients who had received in-patient treatment with digoxin prior to death (therapeutic group) and in a single case of suicidal intoxication. The results were compared with the digoxin levels in the femoral vein blood, myocardium, kidney and liver, and evaluated in light of the medical history of each patient. In the therapeutic group the mean digoxin level was higher in the choroid-retina than in other tissues and body fluids. The range of variation in levels in the choroid-retina following therapeutic doses was comparable to that in the other tissues. An extremely high level of digoxin was present in the choroid-retina in the case of suicidal intoxication. In all cases, levels in the vitreous humor were very low compared to those in the choroid-retina. Hence, it is unlikely that significant distortion of choroid-retinal levels occurs due to postmortem diffusion of digoxin into the vitreous body. Our results indicate that measurement of digoxin levels in the choroid-retina can aid the postmortem diagnosis of lethal digoxin intoxication.

Aged↗
PubMed1992

Measurement of digitalis-glycoside levels in ocular tissues: a way to improve postmortem diagnosis of lethal digitalis-glycoside poisoning? II. Digitoxin.

Postmortem digitoxin levels in the choroid-retina and vitreous humor of patients who had undergone digitoxin therapy (therapeutic group) and in one case of suicidal digitoxin poisoning were measured and compared with levels in femoral vein blood, myocardium, kidney and liver. The results were interpreted in light of the medical history of each patient. The digitoxin level in the choroid-retina of the single case of suicidal poisoning was far higher than the choroid-retinal levels in the therapeutic group. In the latter, variation in choroid-retinal levels was comparable to that in the other tissues. In cases where the choroid-retina of the right and left eyes were examined, digitoxin levels in both eyes were essentially equal. There was no indication of significant changes in choroid-retinal levels due to postmortem diffusion of digitoxin into the vitreous body. Based on these results, determination of digitoxin levels in the choroid-retina could contribute to improving postmortem diagnosis of lethal digitoxin poisoning.

Adult↗
PubMed1990

[Interpretation of postmortem digoxin levels: evaluating a "corrective factor" for postmortem blood digoxin concentration].

Interpretation of postmortem serum digoxin levels is made difficult above all by a possible prefinal or postmortem rise in digoxin concentrations in the blood. To compensate for this postmortem increase, Eriksson et al. (1984) divided the level of postmortem digoxin in femoral venous blood by a factor of 1.5; in the opinion of these authors, postmortem digoxin levels still exceeding "therapeutic levels" after division by 1.5 are an index of digoxin overdose. The diagnostic value of this "correction factor" was investigated. In 56 cases with documented digoxin medication, samples of postmortem femoral venous blood were taken and the level of digoxin determined. In none of the cases had there been a clinical diagnosis of digoxin intoxication. Fifty percent of the measured values were above "therapeutic levels" (0.7 ng/ml to 2.2 ng/ml). Following division by 1.5, 20% of the cases still showed levels exceeding 2.2 ng/ml; the highest "corrected" value was 4.44 ng/ml. Taking into account the length of time between final dosage and death, individual differences in sensitivity to digitalis glycoside, and the complexity of ante- and postmortem dispersion processes, we concluded for the cases we studied that an (undetected) digoxin overdose was not even likely in those cases whose postmortem values after division by 1.5 lie above "therapeutic levels". The "correction factor" proposed by Eriksson et al. (1984) is only of limited diagnostic value; at best the "corrected" values can give an approximate indication of the corresponding antemortem serum digoxin concentrations. In particular, "corrected" values only a little above "therapeutic levels" could not confirm suspicion of an overdose with sufficient certainty.

Adolescent↗
PubMed1990

The extent of aspartic acid racemization in dentin: a possible method for a more accurate determination of age at death?

In the current study the objective was to find to what extent a reliable determination of age at death is made possible by establishing the degree of aspartic acid racemization in the dentin of teeth. The results of the investigation of 46 teeth are in agreement with the values found by other authors. The method presented makes a reproducible and accurate estimation of age possible. We intend to elaborate and improve this promising method for determination of age at death. The relevant points are presented here.

Adolescent↗
PubMed1988

The effect of unilateral naris occlusion on cell dynamics in the developing rat olfactory epithelium.

The effect of unilateral naris occlusion on the cellular dynamics of developing olfactory epithelium was investigated in postnatal rats. Nares of rat pups, at 1, 5, and 10 d postnatally, were cauterized; after a 30 d survival period, the olfactory mucosa was examined histologically, and quantitative estimates were made of total number of receptor neurons (together with basal cells), supporting cells, and epithelial thickness. In each group, there were significant differences between occluded and patent sides in total numbers of neurons and in epithelial thickness but no difference in number of supporting cells. The differences were greater in the animals that had been occluded for 1-30 d than in the 5-35 or 10-40 d groups, suggesting that the earlier postnatal days are more sensitive to the effects of occlusion. We evaluated the number of mature olfactory neurons by staining immunohistochemically with an antibody against olfactory marker protein. There were no differences in the number of mature receptor neurons between the occluded and non-occluded sides, indicating the effect of naris occlusion was on the neurons in the immature and/or the "almost mature" population. Using 3H-thymidine autoradiography, we determined that there was a 40% reduction in the rate of neurogenesis in the animals occluded 1-30 d after birth. Further, the rate of cell proliferation in nasal respiratory epithelium declined by approximately the same amount.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗