Pachydermoperiostosis. An ultrastructural study

BACKGROUND: Pachydermoperiostosis (PDP) is a rare genetically determined disease belonging to the group of hypertrophic osteoarthropathies. Its aetiopathogenesis remains unclear. Most hypotheses favour an exogenous stimulation of fibroblasts. METHODS: A clinically typical patient with PDP was studied by electron microscopy with particular reference to the dermis and its cellular constituents. Fibroblasts from involved skin were cultured and studied in comparison with control cells. RESULTS: Remarkable modifications of the structure of the dermis were observed, encompassing irregular caliber of collagen fibres, extracellular deposits of microfibrils and of amorphous granular substance corresponding to the Alcian blue positive deposits seen by conventional histochemistry. The in vitro growth of fibroblasts was normal. CONCLUSION: Authors reviewed aetiopathogenic hypotheses. Our data suggest a genetically determined alteration of extracellular matrix production by fibroblasts as a possible explanation for the development of PDP.     

Chloroquine-induced achromotrichia. An ultrastructural study

BACKGROUND: Electron microscopy examination of scalp biopsies from a patient with chloroquine achromotrichia gave elements concerning the pathogenesis of chloroquine-induced achromotrichia. CASE REPORT: A 21-year old light brown-haired patient developed achromotrichia after four months of treatment with chloroquine for subacute lupus erythematosus. Hair bleaching completely regressed 5 months after discontinuing chloroquine despite replacement with hydroxychloroquine. During the achromatrichia phase, many ultrastructural anomalies were observed in the hair root melanocytes: the nuclei were small and densified, and there was an accumulation of immature melanosomes in the cytoplasm; these melanosomes, mainly in stage II, were rarely transferred to keratinocytes. After recovery from the achromotrichia, melanocytes displayed a normal aspect. DISCUSSION: Pathophysiological disturbances leading to chloroquine induced achromotrichia are still unclear. The ultrastructural study of hair follicles in our patient show that under chloroquine action melanocytes become unable to perform complete melanin synthesis and to produce normally melanized melanosomes which may be transferred to keratinocytes. Non-melanized or poorly melanized melanosomes accumulate in the melanocytes which finally become inactive cells. These findings suggest that achromotrichia is induced by a toxic effect of chloroquine on the melanocyte.     

Sporadic visceral myopathy with inclusion bodies. A light-microscopic and ultrastructural study

We report the clinical and pathologic findings of two patients with sporadic visceral myopathy. Both presented with chronic intestinal pseudo-obstruction that necessitated colectomy. Microscopically, typical changes of primary visceral myopathy were present, including variable fibrous replacement of the muscularis externa and vacuolar degeneration of myocytes. In addition, the muscle cells contained cytoplasmic inclusions that have only been recently reported in visceral myopathy. These inclusions were numerous and easily visible in routine hematoxylin-eosin-stained sections but greatly enhanced by periodic acid-Schiff staining. They were reactive immunohistochemically at their periphery and were seen to be myofibrils at various stages of degeneration on electron microscopy. Inclusions were present in both muscularis externae and muscularis mucosae and were identified in mucosal biopsy specimens, providing a means of diagnosing this type of myopathic change on endoscopic biopsies.     

The human yolk sac and yolk sac carcinoma. An ultrastructural study

The ultrastructure of the yolk sac of a 39 day old human embryo was studied. The subcellular organization was suggestive of a highly specialized absorptive function proceeding in an exocelomic-viteline direction. These findings, compatible with intense metabolic activity, are at variance with the concept of rapid involution of the yolk sac following completion of its hemopoietic and angiogenetic functions. The speculation is advanced that a potential avenue exists in the yolk sac whereby maternally derived products encounter fetal endoderm. Ultrastructural features in the normal yolk sac were compared to those existing in a tumor showing the "endodermal sinus" pattern, and reviewed in the light of the pertinent literature. These findings support the concept that attributes an endomesoblastic derivation to such neoplasms.     

Venous hemangioma. An immunohistochemical and ultrastructural study

OBJECTIVE: To elucidate the roles of integrins in tumorigenesis, progression, differentiation, invasiveness and metastasis, and the role of the integrin alpha 5 subunit in hepatocellular carcinoma (HCC). METHODS: 79 formalin-fixed sections of hepatocellular carcinoma (HCC) were obtained. The integrin alpha 5 subunit was measured by immunohistochemistry assay (ABC method). RESULTS: In 79 cases of HCC, cancerous tissues had lower expression than their adjacent non-tumor tissues (32.9% vs 81.0%, P < 0.01). The alpha 5 positive rate in small HCC (= < 5 cm in diameter) was higher than large HCC > 10 cm in diameter), being 55.6% and 10.0% respectively. Well-differentiated HCC expressed higher alpha 5 than poorly differentiated ones. The alpha 5 positive rates were lower in highly invasive HCC than those to low invasive ones. CONCLUSION: Our study indicated that expression of the integrin alpha 5 subunit is correlated with growth, differentiation, invasiveness and metastasis of HCC. It is possible that alpha 5 subunit is a negative regulator to these biological parameters of HCC.     

Subclinical surface alterations of human pleura. A scanning electron microscopic study

Pleuritis or pleural effusion frequently develops in patients with pneumonia or heart failure. Most of these pleural changes regress without intrapleural intervention. The detailed mechanisms of the regression of the pleural changes in humans are not well documented. We studied the parietal pleura of nine patients with lung cancer and two patients with coronary artery disease by scanning electron microscopy (SEM). All patients had neither radiographic nor gross evidence of pleural disease but all had mixed surface alterations by SEM. Focal denudation of mesothelial cells was common. Deeper injuries exposed thick and thin interweaving collagen bundles. Patchy depositions of amorphous or crystallized fibrin covered normal and damaged pleural surfaces, frequently admixed with macrophages, red blood cells, and tissue debris. Reactive mesothelial cells appeared to proliferate over the fibrin. Our findings suggest that subclinical pleural alterations occur often in patients with pulmonary or cardiac diseases and that an intact pleural surface in those patients is restored mainly by the proliferation of reactive mesothelial cells.     

Development of the thyroid gland in the rat fetus in vivo. An ultrastructural and radioautographic study

A study of the differentiation of the thyroid follicles was carried out in rat fetuses between day 14 of pregnancy, when cellular polarization begins and day 18, when completely formed follicular lumina are differentiated. After day 18, only the shape and the size of the lumina undergo modifications. The mechanism of folliculogenesis involves the participation of several structures. At 14 days of pregnancy, adherens type contact zones with membrane densification appear between the cells. These junctional zones spread out and form infoldings which deeply penetrate the cytoplasm. Golgi vesicles migrate to these zones and they fuse among themselves and with the contact membranes : follicular cavities result which can be recognized as soon as day 16 of pregnancy. A radioautographic study showed the beginning of iodide organification at 17 days 11 hours of pregnancy. From this time onward silver grains were seen over the follicular cavity, even it is still incompletely formed.     

Papillary cystadenoma of the epididymis. An ultrastructural and immunohistochemical study

Papillary cystadenoma of the epididymis is a rare neoplasm that is sometimes associated with von Hippel-Lindau's syndrome. Electron microscopic study of the present case revealed that neoplastic cells contained abundant glycogen granules and large lipid droplets, but a few organelles. On the apical surface there were numerous microvilli and a few single cilia, but no ciliated cells. Subepithelial basal lamina was noted, but it was occasionally disrupted. Furthermore, microvilli sprang from the circumference of the small tumor-cell nest and became associated with matrix components (microvillus-matrix associations). On immunohistochemical study, neoplastic cells showed epithelial characteristics, but positive reactivity for S-100 protein. These findings resembled those of the epithelial cells of the efferent ductules of the epididymis. In the stroma, prominent vasculature was characteristic and fenestrated-type capillaries were found in the peripheral portion of the tumor. Papillary cystadenoma of the epididymis may originate from non-ciliated epithelial cells of the efferent ductules.     

Malignant mesothelioma of the pleura. Morphometric study

Between April 1994 and October 1996 on account of complicated obstruction of the lacrimal pathways temporarily into the lacrimal efferent system 144 silicone cannulas were inserted in 127 children aged 4 months to 9 years. A standard procedure was used, with the children under general inhalation anaesthesia, in collaboration of an ophthalmologist and otorhinolaryngologist using endonasal optics. By October 1996 100 cannulas were extubated, on average after 4.1 months. The effectiveness of the procedure evaluated on the basis of clinical manifestations and the Dye Disappearance test is 81%.     

A morphological study to elucidate the differences in visceral pleura in young and old mice]

This study was conducted to determine the pharmacokinetics and pharmacodynamics of pyridostigmine given as 30 mg of pyridostigmine bromide every 8 hours in healthy subjects. Plasma pyridostigmine concentration and red blood cell acetylcholinesterase activity were measured in blood samples collected during a 3-week period. Population analysis was performed using standard pharmacokinetic and pharmacodynamic models with the nonlinear mixed-effect modeling software (NONMEM). The pharmacokinetic model that best fit the pyridostigmine plasma levels was a two-compartment open model with first-order absorption, a lag time, and first-order elimination from the central compartment. The pharmacodynamic model that best fit red blood cell acetylcholinesterase activity was an inhibitory Emax model with an effect compartment linked to the central compartment. The results showed that the pharmacokinetics of pyridostigmine bromide are both gender and weight dependent. The pharmacodynamic effect does not lag significantly from the plasma concentration and returns to near normal within 8 hours. With the present dosage regimen of 30 mg every 8 hours, 30% of individuals may not have red blood cell acetylcholinesterase inhibition > 10% at the time of the trough.     

Eosinophilic granular ceels in oligodendrogliomas. An ultrastructural study

In three cases of oligodendrogliomas, atypical cells rich in eosinophilic cytoplasm, resembling plump astroyctic or astroblastic cells, were studied under the electron microscopy. These cells showed finely granular cytoplasm with routine hematoxylin-eosin preparation; ultrastructurally, they exhibited abundant, round cytoplasmic bodies of autophagic-vacuole type, in addition to other fine structures characteristic of oligodendroglioma cells.     

An ultrastructural pathological study of pterygium

OBJECTIVE: To study the ultrastructural changes of pterygium. METHOD: The pathological ultrastructure of pterygium was studied by Hu-12A transmission electron microscopy in 14 specimens. RESULTS: The result indicated that normal and abnormal elastic fibers and collagenous fibers existed in the pterygium. As hyperplastic fibers intruded into the corneal subepithelium, Bowman's membrane was broken. To a certain extent, blood vessel multiplication and degeneration were found in the pterygium. One of the important factors was blood vessel multiplication and degeneration which affected the occurrence and development of pterygium. CONCLUSION: Multiplication and degeneration of elastic and collagenous fibers were the prominent pathological changes, and the pre-elastic fibers and denatured elastic fibers were the main compositions of pterygium.     

Goblet cell carcinoid of the appendix. An ultrastructural and histochemical study

In a patient with a goblet cell carcinoid tumor of the appendix, light and electron microscopical studies demonstrated mucinous material and enterochromaffin granules within the same cell. Transitions between cells containing primarily mucin and cells containing numerous argentaffin granules were observed. Fluorescence studies demonstrated that the tumor cells contain biogenic amines.     

An ultrastructural study of the phagocytosis of Burkholderia pseudomallei

Burkholderia pseudomallei causes melioidosis and is believed to be an intracellular pathogen in human and animal disease. The uptake of B. pseudomallei by mouse peritoneal macrophages and cells in tissue culture was examined by electron microscopy. In all the systems studied B. pseudomallei were phagocytosed and apparently inhibited the normal processes of intracellular killing. Destruction of the phagosome membrane occurred and the bacteria escaped into the cytoplasm.     

Acute murine adrenalitis induced by reovirus 3. An ultrastructural study

Reovirus 3 infection of neonatal mice, although characterized primarily by encephalitis, hepatitis, and pancreatitis, also induces an adrenalitis. Histologically, the latter is characterized initially by foci of coagulative necrosis which later enlarge and become surrounded by leukocytic infiltration. Ultrastructurally, the virus was shown to replicate in the paranuclear region of mainly adrenocortical cells but also medullary and endothelial cells. Apoptosis is the most common form of necrosis exhibited and is quickly followed by an infiltration of mononuclear phagocytes which eventually ingest the virus and the cellular debris.     

Functioning oxyphil adenoma of parathyroid gland. An ultrastructural and biochemical study

Oxyphil cells and oxyphil cell adenomas of parathyroid glands are, in most instances, regarded to be nonfunctioning. Although 21 cases of hyperparathyroidism associated with parathyroid oxyphil cell adenoma have been reported, secretion of hormone by these tumors has not been conclusively demonstrated. A parathyroid adenoma, diagnosed by light microscopy as oxyphil type, together with the results from ultrastructural and biochemical studies of the patient's adenomatous tissue, are reported here. The patient, a 64-year-old male, was found to have elevated serum calcium, low serum phosphorus, and elevated serum immunoreactive parathormone: findings consistent with hyperparathyroidism. After excision of two small normal-appearing glands and one greatly enlarged (1.9 g) parathyroid gland, those laboratory values returned to normal. Light microscopy of the enlarged parathyroid indicated that it consisted almost entirely of an oxyphil adenoma. Electron microscopy revealed that the adenoma was composed mainly of mitochondria-rich oxyphil cells but also of interspersed transitional oxyphil cells and rare scattered chief cells. Golgi zones, rough endoplasmic reticulum, and prosecretory and secretory-like granules were observed in some oxyphil cells, in most transitional oxyphil cells, and in the infrequent chief cells. Thus, many of these cells appear to contribute to the production and secretion of parathormone. Biochemical studies performed directly on the adenomatous tissue demonstrated that it was able to synthesize proparathormone and parathormone, although the proportion of hormonal peptide synthesis relative to that of the total protein synthesis in this tissue was much smaller (0.9%) than that found in normal parathyroid tissue (5.7%). There was a small increase in immunoreactive parathormone when the adenoma tissue was incubated in a low-calcium medium. These findings indicate that this oxyphil adenoma of the parathyroid gland synthesized and secreted parathormone, apparently to some extent autonomously, but suggest that its capacity to do so was largely dependent on its component of cells other than fully developed oxyphil cells, such as transitional oxyphil cells.     

Synaptic organization of the human striatum: a postmortem ultrastructural study

Converging with psycho-social research findings, animal and human laboratory studies indicate that behavioral alternatives are important determinants of drug-taking. To investigate associations between how early adolescents spend their time, i.e. their behavioral repertoire and drug use (use of marijuana, crack/cocaine or inhalants), we analyzed data from an epidemiological sample of 1516 urban middle-school students who had completed private interviews in spring 1993. The interview included a 36-item questionnaire to assess how frequently the youth engaged in different activities; history of drug-taking was assessed separately. Multiple logistic regression was used to estimate associations between drug use and each of seven behavioral domains as well as sex, age and racial-ethnic status. Youths spending a great deal of time working for pay and assuming other adult-like roles were more likely to have initiated drug use (estimated odds ratio, OR = 3.49; p = 0.002). Those who spent much time in religious activities were less likely (OR = 0.2, p <0.001). An exploratory search for interactions disclosed other associations that merit attention in future research. These results corroborate evidence on the potential etiological significance of behavioral repertoire in relation to risk of drug use.     

An ultrastructural and ultrahistochemical study of the placenta of the diabetic woman

An ultrastructural and ultrahistochemical study has been made of placentae from seven women, all of whom were established diabetics before the onset of pregnancy. None of these women had suffered from any of the hypertensive complications of pregnancy. Patchy focal syncytiotrophoblastic necrosis was evident and indirect evidence of syncytial damage was seen in the form of marked cytotrophoblastic hyperplasia. The syncytial necrosis appeared to be lysosomally mediated, possibly as a result of altered intracellular pH. Occasional cytotrophoblastic cells also showed degenerative changes. Most of the villous trophoblast was, however, morphologically normal and showed features suggestive of normal or increased synthetic, transfer and excretory activity. Focal thickening of the villous trophoblastic basement membrane was seen and this did not appear to be due to deposition of immune complexes. The endothelial cells of the villous capillaries appeared unduly immature but no evidence was seen of immune complex deposition in these vessels or of diabetic angiopathy. It is concluded that the diabetic's placenta shows a consistent pattern of abnormalities which appear to be a direct result of the diabetic state.     

An ultrastructural study on resting cyst of Euplotes encysticus

For resting cysts of Euplotes encysticus, in their various ciliatures, most of the ciliary shafts above the cilia kinetosomes are degenerated, or preserve their kinetosomes only. Sometimes, kinetosomes of certain frontal and ventral cirri are also disintegrated and disappeared. For remaining cilia, on their shafts, peripheral doublet microtubule (MT) and central pair of MTs still possess their structural pattern of "9 + 2". In few ciliary shafts, the phenomena of 2 sets of "9 + 2" structures surrounded by a common sheath can also be seen. At the center of kinetosomal peripheral triplets (triplet MTs), aggregates of MT-like structures are formed. For kinetosomal accessory structures, only residues of inter-kinetosomal connections and ciliature brackets can be seen. No MT layers can be seen under the pellicles of non-ciliated cortex. At the ciliated cortex, there are peripheral MT layers (corresponding to sub-pellicular MT layers) within the ciliature cavity, MT ribbons at (and near) the deeper parts of ciliature, and scattered MT groups. Besides, various shapes of ciliary shafts structures are seen within cortical vesicles of ciliated regions. Nuclear pores of macronucleus enlarged apparently, reduced in number, and, chromatin attached on the inner membrane of these nuclear pores.     

An ultrastructural study of the intimal hyperplasia in healing microarterial anastomoses

The purpose of the study was to investigate the ultrastructure of intimal hyperplastic cells. End-to-end microarterial anastomoses were studied in a rabbit free-tissue-transfer model. There were five experimental groups, with 1, 3, 7, 14, or 28 days follow-up. At sacrifice the anastomoses were tested for patency and then examined by light and electron microscopy. At days 1 and 3 the repaired intima was covered with macrophages and extravasated erythrocytes. At day 7 spindle-shaped fibroblasts with copious rough endoplasmic reticulum were seen. Some of these cells also contained pinocytotic vesicles, filaments with focal densities, and subplasmalemmal attachment sites, the features of smooth muscle cells. At day 14, more cells contained smooth muscle features and these features were also more pronounced. These young myofibroblasts were plumper than adjacent fibroblasts. At day 28 mature myofibroblasts with a full complement of organelles were present. The results, therefore, supported the hypothesis that myofibroblasts are present in the intimal hyperplasia of healing microarterial anastomoses.