Postoperative thrombotic thrombocytopenic purpura following cardiovascular surgeries.

Among 47 patients with thrombotic thrombocytopenic purpura (TTP), 8 patients were diagnosed to have postoperative-TTP. Two patients underwent vascular surgery, 5 patients coronary artery bypass grafts, and 1 patient resection of myocardial sarcoma. Prior to surgery, all patients except one had normal hemograms and platelet counts, and blood smears showed no schistocytes. Five to 19 days after surgery, all 8 patients developed postoperative TTP, which clinical feature was characterized by unexplained progressive encephalopathy, thrombocytopenia, and microangiopathic hemolytic anemia. In addition, in 3 patients, progressive gangrene of the toes also developed. Four patients achieved complete remission following exchange plasmapheresis and 1 patient spontaneous remission. Due to complicated surgical settings after surgery, recognition of TTP was often delayed and it contributed to death in 3 patients despite treatment with exchange plasmapheresis. In view of occurrence of postoperative TTP following cardiac and vascular surgeries, pathogenic mechanism for postoperative TTP may be explained on the basis of injury of diseased endothelial surface and release of a humoral factor(s) that results in platelet aggregation in the capillaries and arterioles. Our experience with these cases indicates that TTP may occur as a serious complication of cardiac and vascular surgeries, and early recognition of the diagnosis and institution of exchange plasmapheresis are of paramount importance for favorable outcome.

Effect of vasectomy on the ultrastructure of epididymal epithelium in rhesus monkey.

Ultrastructural changes in the epididymal epithelium and the fate of accumulating spermatozoa were examined in the vasectomized rhesus monkey (Macaca mulatta). Accumulation of spermatozoa resulted in an increase in the diameter of the tubule and its lumen. Ultrastructure of principal cells revealed that they continue to perform both secretory and absorptive functions after vasectomy. The rough endoplasmic reticulum, Golgi complex, and mitochondria were well developed in the principal cell. Bulging of the apical portion of principal cells and membrane-bound structures in the lumen suggests an increase in apocrine secretion. An increase in the number of vesicles, vacuoles, and multivesicular bodies in the principal cells indicates an increased absorptive activity. Increased absorptive function was also evident in the apical cells. Macrophages with sperm remnants were seen in the lumen, and occasionally in the connective tissue. The principal or only mechanism of sperm disposal after vasectomy appeared to be intraluminal endocytosis by macrophages.

Ultrastructural changes in the principal cells of epididymis of adult rhesus monkey (Macaca mulatta) after castration and androgen replacement therapy.

The epididymal epithelium from adult castrated and androgen supplemented, castrated rhesus monkeys was examined with transmission electron microscope. Ninety days after bilateral castration the tubular diameter of all the regions of the epididymis, viz. the initial segment, caput, corpus and cauda portions of epididymis was reduced and was accompanied by a drop in cell size. There was a marked decrease in the number and size of microvilli on the luminal surface. The invaginations of apical membrane into the cell cytoplasm became less prominent. There was a reduction in the amount of smooth and rough endoplasmic reticulum, and Golgi complex. Mitochondria accumulated in the apical cytoplasm. Several vacuoles often associated with lipofuscin pigment granules were common in the cytoplasm. These findings suggest a reduction in both the absorptive and secretory functions of the principal cells. Following androgen replacement therapy for 30 days in monkeys that were castrated 60 days earlier there was a recovery of structural features in the epithelium to near normal state.

Effects of sodium deoxycholate on the mechanical and electrical activities and ultrastructure of guinea pig atria.

The mechanism of cardio-inhibitory effects of sodium deoxycholate (DOC) was investigated by studying its effects on the contractility, action potentials (APs) and ultrastructure of guinea pig atrial preparations. DOC (10(-7)-10(-4) M) caused reversible negative ino- (NIE) and chrono-tropy in spontaneously beating (SBA) and NIE in electrically driven left (EDA) atria. At higher doses (greater than or equal to 1.10(-3) M) DOC caused irreversible inhibition of contractions. Atropine (10(-7)-10(-4) M) failed to inhibit both the reversible and irreversible effects of DOC. The NIE due to lower doses of DOC (less than or equal to 1.10(-4) M) was inhibited by higher [Ca2+]0, isoprenaline (10(-6)-10(-4) M), and noradrenaline (10(-6)-10(-5) M), which did not alter the dose of DOC required for the irreversible and complete NIE. In lower doses (10(-7)-10(-4) M) DOC caused a reversible inhibition of the AP durations at -20 and -40 mV (APD20 and APD40, respectively), but increased the AP duration at 90% repolarisation (APD90). At higher doses (greater than 5.10(-4) M) it caused an irreversible membrane depolarization, reduction in APD20 and APD40, and complete cessation of electrical activity. The ultrastructural changes in atria treated with 1.10(-4) M DOC were characterized by poorly delineated glycocalyx and at greater than 1.10(-3) M by disruption of sarcolemma and sarcoplasmic reticulum and swelling disruption of mitochondria. Taken together these observations show that DOC caused reversible and irreversible inhibition of atrial contractions at low (10(-7)-10(-4) M) and high (greater than 5.10(-4) M) concentrations, respectively, by different mechanisms. The former effect is due to inhibition of Ca2+ channel activity and the latter due to its detergent property causing removal of subcellular components.

Epididymal basal cells in rhesus monkey (Macaca mulatta): ultrastructural changes after castration and androgen replacement therapy.

The ultrastructure of epididymal basal cells in adult castrated and castrate-androgen supplemented rhesus monkey was studied. Due to reduction in the height of the epithelium, three months after castration their number appeared to have increased. In the initial segment dark basal cells occupied more area in the epithelium and their cytoplasm showed the presence of large vacuoles. Cells that resembled dark basal cell were found at all heights of the epithelium. In all the segments, dark basal cells developed pseudopod-like structures. Pale basal cell cytoplasm was filled with lipofuscin pigment granules. Androgen replacement therapy for 30 days prior to autopsy at 90 days did not bring about any significant changes in the ultrastructure of both the types of basal cell. However, the size of the dark basal cell appeared to have decreased. The possible role of basal cells in the disposal of products accumulated in the principal cells under normal and altered endocrine conditions in discussed.

Ultrastructure of the epididymal epithelium of rhesus monkey (Macaca mulatta).

The regional fine structure of the epithelium lining the epididymis of the rhesus monkey has been investigated. Tall, prismatic principal cells constituted the major part of the epithelium. Their basal plasma lemma showed presence of caveolae and the luminal surface was studded with stereocilis. Presence of numerous desmosomes and tight junctions between adjacent principal cells suggested the existence of blood epididymis barrier. Ultrastructural evidence is presented in support of high lysosomal turnover, absorptive and secretory functions in these cells. Apocrine secretion was evident only in the principal cells of initial segment. Of the two types of basal cell, dark and pale, the latter revealed presence of lipofuscin pigment suggesting their scavenger role in the epithelium.

Ultrastructural study of epidermal Langherhans cells in leprosy.

ATPase staining and ultrastructural study of skin biopsies from six patients of leprosy (2TT, 4LL) and three normal subjects was carried out to study Langherhans Cells (LC). ATPase staining showed normal counts of LCs in tuberculoid patients, while significant reduction was observed in lepromatous cases. Electron microscopy revealed morphological changes in LL cases in the form of dense matrix and indistinct cristae of mitochondria; decreased number of lysosomes and rough endoplasmic reticulum; and numerous vacuoles in cytoplasm. TT cases showed normal morphology. Possible role of Langerhans Cells in pathogenesis of leprosy is discussed.

Ultrastructural changes in the neural lobe of the rat pituitary following nicotine pretreatment.

The effect of nicotine on the ultrastructural changes and hormone contents of the neural lobe of the pituitary were studied in the rat. Nicotine caused a significant release of both vasopressin and oxytocin from the neural lobe. The examination of the neural lobe with electron microscope reveals the nerve terminals depleted of neurosecretory granules. These results suggest that a definite correlation exists between hormone contents and ultrastructural morphology.

Ultrastructural changes in rabbit testis and epididymis following vasectomy: a long term study.

The Ultrastructural changes in testis and epididymis were studied in rabbits following 18 months of bilateral vasectomy. No fine structural changes were observed in seminiferous tubules and all stages of spermatogenesis appeared normal in most of the sample studied. Intracellular spaces in the spermatogonia cytoplasm may denote ionic deficiency. Digestion of sperms to some extent in the lumen of seminiferous tubules was denoted by the presence of round membrane bound bodies which may be remnants of digested cytoplasmic organelles and sperm parts. Cells of the epididymal epithelium showed normal characteristics. Electron dense bodies (lysosomes) were more prevalent in the supranuclear region of principal cells suggesting increased resorption capacity of caput epididymis after vasectomy. Presence of large oval bodies in the lumen needs further investigation.

Scanning and transmission electron microscopy of the ependyma of the fourth ventricle in the monkey brain.

The ependymal structure of the fourth ventricle floor of adult rhesus monkeys was investigated using both scanning and transmission electron microscopy. Each half of the floor exhibited dense ciliation which decreased towards the median sulcus. The area postrema and the facial colliculus lacked cilia and were covered with non-ciliated ependymal cells. Along the entire length of the median sulcus supraependymal globular protrusions were seen. Over the rostral and middle thirds of the sulcus these protrusions exhibited interwoven ridges. At the former situation they were closely approximated but at the latter they were on the surface of non-ciliated nodules which were lying amongst sparsely ciliated cells. In the caudal third these protrusions presented smoother surfaces without any structural details over them. Transmission electron microscopy through the upper two thirds of the median sulcus revealed these surface protrusions to be non-ciliated cells having long and profuse network of interwoven microvilli over their luminal surface. These cell bodies exhibited well-defined supranuclear Golgi complexes, vesiculated rough and smooth surfaced endoplasmic reticulum, free ribosomes and polyribosomes, few electron dense granules, network of microtubules and light and dense multivesiculated bodies. These features suggested a secretory and/or absorptive role, rather that autophagy to these surface specialization.

The effect of estrogen on the tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta).

The effect of 3 doses of estradiol dipropionate (EDP) on tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta) was studied under both light and electron microscopy. EDP at a dose of 5 microgram/kg/day for 6 consecutive days changed differentiation of the epithelial cells into clear and dark cell-types; ciliogenesis, formation of some ciliary buds and even a few cilia were also induced in some clear cells throughout the tubal epithelium. Development of ciliated cells with fully formed ciliary apparatus was accelerated at 10 microgram/kg dosage. The secretory granules (SG) appeared at this dose in some nonciliated cells of the infundibular and ampullary but not the isthmic segments of the tube; some of the infundibular secretory cells, so formed, exhibited even a tendency to secrete. Nearly complete maturation of the tubal epithelium occurred at 20 microgram/kg dose; further signs of secretory activity appeared in all tubal segments. The results indicated that--(i) Nearly complete transformation of tubal epithelium of the immature animal into one of the adult type could be achieved by EDP at a dose not less than 20 microgram/kg under the present conditions. (ii) The response of undifferentiated cells to EDP differed depending upon the location of the epithelial cell within the tube and nature of the cell-type to be formed. (iii) The mode of tubal secretion in this infra-human species was probably apocrine.

The effect of estrogen withdrawal upon the tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta) pretreated with estradiol dipropionate.

Immature ovariectomized rhesus monkey (Macaca mulatta) were injected intramuscuarly with estradiol dipropionate (EDP) at a dose of 20 micrograms/kg/day for 6 consecutive days and were sacrificed at days 1, 3, 8, 13 and 25 following withdrawal of the hormone. The overall height of the epithelia of the infundibulum (Inf), Ampulla (A) and the isthmus (I) and the status of the ciliated and nonciliated cells therein were observed under both the light and electron microscope and those observed at days 3-25 were assessed against those found at day 1 (control values). The EDP effect on the above aspects did not change significantly at days 3 and 8 as compared to day 1. There was rather an increase of such hormone impact on day 8: this is indicated by the observations that the nonciliated cells possessed a greater number of secretory granules (SG) and/or exhibited signs of higher secretory activity. Possible neosynthesis of SG was discerned on days 3 and 8. Retrogressive changes in the epithelia and in the constituent cell types were evident on day 13; those advanced further on day 25 but to different degrees in different segments. The changes were highest in Inf following by those in A and I in order: Inf greater than A greater than I. All these changes were described and commented upon. It is concluded that the estrogen impact lasts for some time after its withdrawal and that the nature of subsequent regression of any epithelium and of the celltype therein is determined by their position within the tube.

Ventricular surface of rabbit hippocampus: a scanning electron microscope study.

Portions of the ependyma were obtained from the hippocampus of adult rabbits and processed for scanning electron microscopy. The major part of the ependymal surface was covered with a dense layer of cilia, some of these cilia showed bulbous preterminal enlargements. Irregularly arranged pits of variable diameter were also seen. Pes hippocampi showed fewer cilia and deeper furrows than did the remainder of the hippocampus.

Differential response of the ampullary and isthmic cells to ovariectomy and estrogen treatment: an ultrastructural study.

Ultrastructural response of the ciliated and secretory cells from the ampullary and isthmic parts of the oviduct was studied in ovariectomized and ovariectomized plus estradiol dipropionate (EDP) treated rabbits. Ovariectomy did not significantly affect the cilia in the ampullary epithelium; degenerative signs, however, appeared overtly in the isthmic cilia. EDP at either 1 microng/kg or 5 microng/kg doses raised the number of cilia/cell in either tubal segments. For comparable change isthmic cilia seemed to require a higher dosage of the estrogen. Ovariectomy led to the depletion of the secretory granules (SGs) from the secretory cells of either tubal segments. EDP at both the doses induced formation of the SGs; this is more remarkable in the isthmic cells. Merocrine type of secretions were observed from the secretory cells of either segments but only at the high dose of estrogen. The findings are discussed in the backdrop of current knowledge.