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PubMed1995

Changes in adhesive force between the retina and the retinal pigment epithelium by laser photocoagulation in rabbits.

A closed eyeball model was designed to estimate the chorioretinal adhesion of the laser-photocoagulated region. We used it to measure the duration of development of retinal detachment during vitrectomy before and after killing the test rabbits. During testing, negative pressure was applied into the vitreous cavity of the pigmented rabbits. Laser burns were produced in the posterior retina by exposure to an argon blue-green laser beam with a focus diameter of 200 microns of 0.1 to 0.2 second duration and 150 to 250 mW intensity. One hour and one, two, five, seven and fourteen days following laser photocoagulation, vitrectomy was done with a cutting rate of 500 per minute, aspiration pressure of 50 mmHg and infusion pressure of 55.2 mmHg. After core vitrectomy, the rabbit was killed with an intravenous bolus of 100 mg sodium pentobarbital solution. After killing the rabbit, the vitreous cavity was continuously aspirated under the pressure of 25 mmHg while the infusion was stopped. The changes of the fundus, especially development of retinal detachment, were observed in the laser-treated and untreated regions before and after killing the rabbit. When retinal detachment was noted anywhere before killing the rabbit, this postmortem change was not observed. One hour following laser photocoagulation, the laser-treated retina was detached during core vitrectomy before killing the rabbit, and the untreated area was not detached. One day following photocoagulation, the retina was intact before killing the rabbit. After killing the rabbit, the laser-treated retina was detached in four minutes and the untreated retina in 18 minutes postmortem.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesiveness↗
PubMed1988

Cerebral perfusion of metabolic inactivators: a new method for rapid fixation of labile lipid pools in brain.

This paper describes a new method for the rapid fixation of labile lipid pools in the brain. Perfusion of the brain with 0.9% saline containing esterase inhibitors (p-bromphenacyl-bromide and diisopropyl fluorophosphate), an antioxidant (nordihydroguaiaretic acid) and a Ca2+ chelator (EDTA) resulted in a substantial reduction in the levels of free fatty acids, a biochemical marker for the degradation of labile membrane lipids. Levels of unesterified polyunsaturated fatty acids in whole brain were decreased by 90-96% as compared to levels in brains perfused with saline alone. Levels of docosahexaenoic acid approximated levels obtained after microwave irradiation. Unlike microwave irradiation, this perfusion technique perserves the cellular structure of the brain, thereby allowing subcellular fractionation with minimal postmortem changes in lipid pools. The release of arachidonic acid during isolation of the P2 (synaptosomal) fraction was completely inhibited by the presence of the metabolic inactivators. The results of this study demonstrate a new and useful technique for the postmortem inactivation of enzymes responsible for the degradation of labile lipids in the brain. Further, the data underscore the key role of phospholipase A2 and Ca2+ in mediating the release and accumulation of free fatty acids in the ischemic brain.

Animals↗
PubMed1983

The human vestibular organs observed by scanning electron microscopy.

In many of the reports dealing with disorders of the human inner ear the histology comes from temporal bone dissection. In the past decade the scanning electron microscope has changed, to a degree, the approach to inner ear investigation. However, many problems remain with adequate preservation of specimens from human temporal bones. Ordinarily, human material is obtained from cadavers at autopsy as soon as possible after death, and postmortem changes are evident. At the Otologic Medical Group, Inc., in Los Angeles, many translabyrinthine operations for acoustic neuromas are performed. This report covers findings from vestibular specimens obtained during surgery for removal of acoustic neuromas (four cases) and during eighth nerve surgery (one case).

Acoustic Maculae↗
PubMed1986

An elemental analysis of archaeological bone from Sicily as a test of predictability of diagenetic change.

Cortical human bone samples from three tightly dated components of a single Sicilian site were chemically analyzed employing the highly sensitive technique of inductively coupled plasma emission spectroscopy. Although the skeletons appeared to be excellently preserved, significant diagenesis was detected. Moreover, a majority of the elements tested showed no constant or linear variation over time, implying that diagenetic change tends not to be a predictable function of duration of interment. Variation among major long bones of a single skeleton was quite high, as was variation across the cortex. The latter may reflect chemical inhomogeneity in bone tissue or may be an artifact of postmortem change. The results demonstrate the hazards of unsuspected and unpredictable diagenesis, which must be controlled before reliable dietary inferences can be drawn.

Adolescent↗
PubMed2000

Pathological changes of human unmyelinated nerve fibers: a review.

In the cutaneous nerves, unmyelinated nerve fibers outnumber the myelinated ones but are scarcely analyzed, especially at autopsy. This indifference toward the pathology of unmyelinated nerve fibers may be due to the necessity of electron microscopic analyses and, more importantly, the obscurity of pathological alteration of unmyelinated nerve fibers in aging as well as in peripheral nerve disorders. The aim of this article is to review (1) the normal appearance including postmortem changes, (2) the age-related changes, and (3) the pathological alteration in various neuropathic and non-neuropathic conditions, of unmyelinated nerve fibers in the sural nerve. For the complete analyses of sural nerve, qualitative and quantitative estimation of unmyelinated nerve fibers in all specimens should be recommended and it sometimes has an important diagnostic value.

Aging↗
PubMed2000

Experimental kerosene poisoning in goats.

Eighteen young native male and female goats were divided into 3 equal groups. Kerosene was given to Groups 1, 2 and 3 as single doses of 10, 20 or 40 ml/kg bw respectively. Clinical signs In-Group 1 were mild behavioral changes and in Group 2 were mild to moderate bloat, coughing and behavioral changes. None of the goats of Groups 1 and 2 died. Goats of Group 3 had severe signs of poisoning and died within 4 h to 11 d after dosing with clinical signs of severe bloat, frequent coughing, vomiting, and expelling of kerosene from the mouth and nose. Star-gazing, depression, recumbency and dyspnea also occurred. Postmortem changes in Group 3 were gangrenous pneumonia, pleuropneumonia, congestion in brain and kidney, perivascular and perineuronal edema in brain tissue, and renal nephrosis.

Animals↗
PubMed1989

Selective cortical neuronal damage after middle cerebral artery occlusion in rats.

We studied histopathologic changes in cerebral cortex of 20 rats after middle cerebral artery occlusion by using the Fink-Heimer suppressive silver impregnation method and conventional stains. At 6 hours after occlusion, Fink-Heimer-stained sections revealed abundant coarsely granular, intensely argyrophilic neurons in the ischemic cortex. These distinctive argyrophilic neurons could be clearly differentiated from neurons that suffered postmortem changes; argyrophilic neurons were present in all layers of the lateral parietal cortex but in only the superficial cortical layers II and III in the parasagittal area of the frontoparietal cortex and the temporo-occipital area. At 24 hours after occlusion as the ischemic region progressed to pannecrosis, argyrophilic neurons were still evident in peri-infarct regions, with more prominent neuritic silver deposits but no changes in number or spatial distribution. Over 2-7 days, the argyrophilic neurons gradually disappeared while many fine silver-impregnated degenerating terminals appeared in the peri-infarct regions. At 3-6 weeks after occlusion, no more argyrophilic neurons were seen in the cortex although degenerating axons were still present in the deep white matter. Our results indicate selective neuronal damage in the superficial cortical layers and massive axonal degeneration in the cerebrum surrounding infarcts. The neuronal damage does not appear to progress beyond 6 hours after middle cerebral artery occlusion. The Fink-Heimer method has many advantages over existing conventional stains for documenting selective neuronal damage in focal cerebral ischemia.

Animals↗
PubMed1996

Lack of toxicity of a non-sporidesmin-producing strain of Pithomyces chartarum in cell culture and when dosed to lambs.

In New Zealand the fungus Pithomyces charturum normally produces sporidesmin, a mycotoxin, which is responsible for the hepatogenous photosensitisation disease known as facial eczema. Cultures from an isolate of P. charturum, which does not produce sporidesmin, were examined by cell culture and by dosing to lambs to determine whether other toxic metabolites were produced. Acute and long term toxicity studies were conducted with the toxic response being assessed by weight changes, postmortem and histological examination of tissues, blood biochemistry and haematology tests. An extract from a sporidesmin-producing isolate was highly toxic in cell culture, while extracts of the nonsporidesmin-producing isolate did not cause a cytotoxic response to HEp 2 cells. After dosing with a sporidesmin-producing isolate, lambs developed liver lesions and clinical signs of facial eczema. Serum biochemistry changes occurred which were consistent with sporidesmin poisoning. Lambs dosed with the nonsporidesmin-producing isolate, at the rate of thirty times the number of spores of the sporidesmin-producing isolate, showed no observable toxic effects. All organs were of normal appearance, and histological examination of tissues, blood biochemistry and haematology results showed no abnormal changes. Similarly, long term dosing of extracts of the nonsporidesmin-producing isolate, at a rate equivalent to 100,000 spores/g of grass, produced no indication of a toxic response. It was concluded that the nonsporidesmin-producing isolate of P. churtarum contained no toxic metabolites in significant concentration.

Journal Article↗
PubMedDate not supplied

Quantitative assessment of cortical synaptic density in Alzheimer's disease.

Significant progress has been made over the last decade in delineating the neuropathological and neurochemical changes in the brains of patients with Alzheimer's disease (AD). Less well studied are the actual synaptic connections of affected areas of the brain, such as the cerebral cortex. Because the final common pathway for neurotransmission involves synaptic integrity, we quantitatively assessed synaptic number and synapse size in lamina III and V of human frontal cortex (Brodmann area 9) in patients with AD and age-matched controls. Samples were also matched for postmortem interval, and artifacts associated with postmortem change were eliminated. We found a significant decrease in synaptic number per unit volume in both lamina, more marked in lamina III (-42%) than V (-29%). In both normal controls and AD brains, there was a negative correlation between synapse number and synapse size as indexed by the length of the postsynaptic density (PSD); cortical samples with fewer synapses had larger synapse size. This appeared to be a compensatory response, rather than a selective loss of small synapses, since the total amount of synaptic contact area per unit volume did not decline in lamina V (despite a 29% loss of synapses); in lamina III it was reduced 11% despite a 42% loss of synapses. The loss of synapses in AD is widespread and significant in frontal cortex; there is observable compensation by enlargement of synaptic size. This compensatory effort is overcome by the continuing loss of synapses in areas most affected by the degeneration.

Aged↗
PubMed1995

[Sudden unexpected natural death from a viewpoint of forensic pathology].

Sudden unexpected natural death (SUND) has several characteristics, such as unknown clinical history, very short course to death, evidence of trauma, interference of postmortem changes and social implications of diagnosis. From these points, SUND involves important challenges in forensic pathology. Presented here are the highlights of our SUND studies which allow scientific speculation into the antemortem pathophysiological course to death and a subsequent accurate diagnosis of the cause of death in SUND cases. 1. Forensic problems of SUND of unknown etiology 1) Do sudden infant death syndrome (SIDS) studies continue endlessly? In Japan there are many cases of sudden unexpected infant death (SUID) which were regarded as SIDS, often without postmortem examination. Pure SIDS should be a diagnosis of exclusion under thorough postmortem examination. Additionally, many SIDS studies have focused on pathogenesis of pure SIDS based on the analysis of so-called SIDS cases described above. In this sense, SIDS studies may continue forever. To clarify whether SIDS is an onion type, that is a heterogeneous disease entity, or bamboo shoot type, a single disease entity with a single cause, it is more vital to accurately search autopsy findings to exclude the cause of death, rather than to study pathogenesis of SIDS. Thereafter, pure SIDS will be carved in relief and we could study the pathogenesis, if it remains in the future. Present in 40% of our SUID cases examined was the existence of viral infection as a cause of death. 2) Pokkuri disease It has long been believed that the main branches of coronary arteries in Pokkuri-disease cases are macroscopically hypoplastic and cause sudden cardiac death. However, our two-dimensional morphometric analysis of the main branches, such as wall thickness, degree of stenosis, lumen area, area within internal elastic lamina, showed no significant differences between Pokkuri-disease cases and age and sex-matched control cases. 2. Information for grasping antemortem pathophysiological state in SUND cases 1) Standardization of the degree of cardiac hypertrophy based on heart weight. In the course of our preliminary examination, we found that heart weight correlates significantly with body length and weight. Therefore, we tried to standardize the range of normotrophy, hypertrophy and hypoplasia/atrophy of the heart based on the correlation between heart weight and body type index calculated by body length and weight (Broca's index). 2) Evaluation of the clinical laboratory data in cadaveric blood. We examined 32 clinical laboratory parameters in cadaveric blood samples obtained from 192 autopsy cases. Behaviour of the laboratory parameters in cadaveric blood in relation to postmortem interval was divided into four types: increased, decreased, no particular tendency and remaining between upper and lower normal value. Parameters included in the last type, which is a useful tool for speculation of antemortem pathophysiology were T-Bil, TTT, ZTT, BUN, Cre, UA, alpha 1- and beta 2-microglobin, T-Chol, GHA1c, TP, A/G, Hb and Hct. A case was demonstrated in which values of clinical laboratory parameters in agonar stage were the same as in cadaveric blood obtained at autopsy. This indicates that caution is necessary in evaluating clinical laboratory data in agonar patients in the emergency room. 3) Diagnostic evaluation of immunohistochemical myoglobin staining in the kidney In order to evaluate the diagnostic value of myoglobin (Mb) staining in the kidney in medicolegal autopsy cases, Mb staining was carried out on the kidney sections of 141 victims, including 59 natural and 82 unnatural deaths. At the same time, Serum and Urine GFR parameters were measured and systemic histological changes were observed on some sections of each kidney. The incidence of Mb positive cases was 74.6% in unnatural, and 25.4% in natural death, indicating the importance of nontraumatic rhabdomyolysis in natural death cases.

Brain↗
PubMed1987

Glycylproline dipeptidyl aminopeptidase and gamma-glutamyl transpeptidase in human hepatic cancer and embryonal tissues.

Changes of glycylproline dipeptidyl aminopeptidase (GPDA) and gamma-glutamyl transpeptidase (gamma-GTP) activities and their subcellular distributions were compared in human hepatic cancer and embryonal tissues. The activity of GPDA in cancer tissues was significantly higher than that found in healthy liver, though there were no significant differences between fetal and adult livers. The placenta, however, had the highest GPDA activity. The activity of gamma-GTP, on the other hand, was increased significantly not only in cancer tissues but also in live tissues adjacent to the tumor, and it was higher in the fetal liver but much lower in the placenta. Subcellular distribution of GPDA was also different from that of gamma-GTP in cancer tissues, especially after postmortem changes. These results suggest the possibility that GPDA has carcinoembryonic characters similar to gamma-GTP, but the mechanisms, whereby serum activities of these two enzymes were increased in hepatocellular carcinoma patients, are different from each other.

Adult↗
PubMed2001

The forensic entomologist in the context of the forensic pathologist's role.

An adequate death investigation requires the combined efforts and cooperation of experts in different disciplines: crime scene technicians, death investigators, forensic pathologists, anthropologists, entomologists, other medical and non-medical professionals. These front-line experts play a crucial role in every death investigation process. The forensic pathologist normally has the legal authority to take charge of the dead body at a death scene and his primary functions are the exterior and interior examination of the cadaver by analyzing the extent of antemortem injuries and the postmortem changes and the recovery of physical evidence. He is responsible for determining how, when and why of any death which is the result of violence, suspicious or unexplained circumstances or a death which is sudden or unattended, defending and explaining the reasons for making these diagnoses in a courtroom. The forensic entomologist can provide invaluable aid in death cases where human remains are colonized by insects and in the overall investigation. His principal role is to identify the arthropods associated with such cases and to analyze entomological data for interpreting insect evidence. He is responsible for determining the period of insect activity according to all the variables affecting insect invasion of remains and their development. The major goal of medico-criminal entomology is to contribute to the determination of the time, cause, manner and place of the investigated death (especially on badly decomposed corpses or skeletonized human remains) with the support of all the elements which can be inferred from the study of insects found on the cadaver or nearby. The application of techniques devised recently in forensic entomology can allow experts in the field to collect strong entomological evidence and provide useful information not only in a death investigation including movement or storage of the remains following death, time of dismemberment, postmortem artifacts on the body but also at the scene, and even more in child neglect, sexual molestation and identification of suspects. As the role of the forensic entomologist at the death scene, at the autopsy and in the laboratory is defined and well known, this paper focuses on the difficulties that could arise if forensic pathologists and entomologists are uncertain about the procedures that they have to follow, do not realize the value of objective findings or fail to evaluate them. Although every forensic case presents a slightly different set of circumstances and has to be tackled individually, the forensic pathologist should work with the forensic entomologist from the visual observations of the cadaver on the scene, through the collection of arthropods and temperature data at the death scene and at the autopsy, up to the final report with the interpretation of entomological and other biological evidence.

Animals↗
PubMed1984

A new model for examining chorioretinal adhesion experimentally.

A method for examining retinal adhesion in vitro is described. Retinal detachment is produced experimentally by injecting Ringer's solution from a micropipette into the retinal pigment epithelial interface. The resulting detachment is a round blister, demonstrating equal retinal adhesion and elasticity in all directions under physiologic conditions. Measurement of hydrostatic pressure in the experimental detachment allowed postmortem changes to be followed up. Normal adhesion was found up to ten minutes after enucleation. Reduced adhesion was evident more than 15 minutes following enucleation; after 25 minutes, adhesion was so poor that blisters could no longer be formed. The loss of retinal adhesion seems to result from the exhaustion of metabolic substrates in the isolated tissue. Local alterations in adhesion, as after photocoagulation, can be detected as characteristic changes in the shape of experimental detachment and indicates enhanced, diminished, or unchanged adhesion. The present method, thus, defines normal conditions, identifies degenerative and artifactual changes, and permits localized changes in adhesion to be differentiated.

Animals↗
PubMed1980

The role of respiratory infection in intrathoracic petechiae. Implications for sudden infant death.

Intrathoracic petechiae are characteristic of the postmortem changes found in sudden infant death syndrome. The presence and distribution of these petechiae have been claimed as evidence for airway obstruction as the mechanism of death. In a group of young, mature rats that were free of infection, hypoxic asphyxia produced an insignificant number of petechiae, whereas in all littermates infected with an enzootic virus (Sendai) large numbers of petechiae with hypoxic asphyxia developed. Rats similarly infected, but killed with an overdose of pentobarbital sodium, had no petechiae. Most importantly, infected rats with unremitting airway obstruction were free of petechiae. Thus, the experimental conditions necessary for the presence of intrathoracic petechiae are profound hypoxia and infection, with persistent circulation and respiratory effort; persistent airway obstruction does not produce petechiae, with or without infection.

Airway Obstruction↗
PubMed1998

Human liver paraoxonase (PON1): subcellular distribution and characterization.

The subcellular localization and different biochemical properties of a human hepatic microsomal enzyme that hydrolyses paraoxon (paraoxonase, PON1) were studied and compared to the paraoxon hydrolase activity found in human plasma as well as in rat liver and plasma. Having evaluated the influence of the postmortem interval by a parallel experiment performed in rats, we conclude that the paraoxonase activity was preferentially localized in the microsomal fraction. The enzyme reaction was optimized according to temperature, pH, buffer, ionic strength, substrate concentration, and enzyme protein concentration. The characterization of human liver paraoxonase included the study of optimum pH, pH stability, heat inactivation assays, and kinetic parameters (K(m) and Vmax). In addition, the enzyme activity showed an absolute requirement for exogenous calcium. The activity was lost after incubation with EDTA and partially restored by the addition of calcium; however, other metals assayed were not able to activate the human liver enzyme as did calcium. Our results support the possible identity between human plasma and liver paraoxonases. In spite of the technical difficulties of this study and the possible interference of the postmortem changes in the results, this article represents the first systematic approach to the characterization of human liver paraoxonase.

Animals↗
PubMed1985

Nuchal cysts syndromes: etiology, pathogenesis, and prenatal diagnosis.

We examined 10 fetuses with nuchal cysts and compared the findings with 32 cases from the literature. Based on their characteristics, we propose that nuchal cysts are signs of four causally and pathogenetically different entities: cystic nuchal blebs present in otherwise normal fetuses as a postmortem change; 45,X fetuses who have a particular appearance and multiple congenital malformations; an apparently autosomal recessive syndrome of multiple cysts (that extend into deep muscular planes), generalized edema, cleft palate, peculiar skeletal characteristics, acutely angulated ribs (producing a bell-shaped rib cage), and shortened long bones; and in fetuses with syndromes that are inherited (multiple pterygium, Roberts) and chromosomal (trisomy 13, trisomy 21) as an unspecific sign representing both primary and secondary lesions.

Abnormalities, Multiple↗
PubMed1988

Biochemical analysis of caudate nucleus biopsy samples from parkinsonian patients.

Biochemical analyses of caudate nucleus biopsy samples from patients with Parkinson's disease undergoing autologous adrenal transplantation were performed. Activity of the dopamine biosynthetic enzyme tyrosine hydroxylase, and concentrations of dopamine and its primary metabolite homovanillic acid were significantly greater than anticipated on the basis of previously published postmortem values. These data suggest that postmortem changes in various biochemical parameters of dopamine function are more rapid than has been generally appreciated. Further analysis of striatal biopsy samples may reveal predictive relationships between striatal indices of dopamine function and therapeutic response to adrenal transplantation.

Adult↗