Giant fluid-filled bulla treated by instillation of antibiotics after percutaneous drainage.

A 46-year-old man was admitted 3 years ago with symptoms of right chest discomfort. A chest X-ray and CT scan revealed an air-fluid level in a previously diagnosed giant bulla in his right upper lung field. Percutaneous drainage of the giant fluid-filled bulla using a pigtail catheter was performed. Instillation of antibiotics was performed twice and the catheter was removed. Two years later almost complete disappearance of the cavity was noted. Although immediate resolution of the giant fluid-filled bulla was not obtainable, the infection was controlled and an invasive procedure avoided.

Dumbbell shaped exophytic and endobronchial lipomatous hamartoma.

A 63-year-old man presented with a dumbbell-shaped mass obstructing his left upper lobe. He underwent a left upper lobectomy for suspected malignancy. An unexpected pathological diagnosis of endobronchial lipomatous hamartoma was made. Only 6 other cases have been reported in the English literature and only two cases were both endobronchial and exophytic.

Multiple cerebral aneurysms associated with cardiac myxoma in a patient with chronic renal failure: how can we resolve multiple cerebral aneurysms?

Left cardiac myxoma and consecutive embolization into the brain is well documented, whereas the association of myxoma with multiple fusiform cerebral aneurysms is rare. A 48-year old female with chronic renal failure had complained of syncope after receiving hemodialysis. An echocardiogram showed a 3 x 4 cm sized myxoma and brain MRI displayed multiple fusiform aneurysms. The myxoma was successfully removed. Postoperatively, she developed status epilepticus. Unfortunately, the patient did not recover and expired due to sepsis.

Insulin secretion and sensitivity during oral glucose tolerance test in Korean lean elderly women.

Impaired glucose tolerance (IGT) and type 2 diabetes including undiagnosed isolated postchallenge hyperglycemia (IPH) are common in the elderly. The aim of this study was to investigate the insulin secretion and sensitivity in Korean elderly lean diabetic women. Forty-one lean women aged 65-88 years took 2 hr oral glucose tolerance test (OGTT) and were stratified according to the WHO criteria (normal glucose tolerance [NGT], n=20; IGT, n=6; and type 2 diabetics, n=15 including seven IPH). HbA1c and fructosamine progressively increased from the NGT to the diabetic subjects (p=0.006 and p=0.001, respectively). Compared with subjects with NGT, the insulinogenic index, a marker of early insulin secretion and the AUC(ins), a marker of total insulin secretion, decreased significantly in diabetic group [0.53 (-0.44 -1.45) vs. 0.18 (0.00 -1.11), p=0.03 and 306+/-165 vs. 199+/-78 pmol/L, p=0.02 respectively]. A significant difference was found in the AUC(c-peptide) among each group (221+/-59 vs. 206+/-34 vs. 149+/-51 pmol/L, p=0.001 for each). The homeostasis model assessment of insulin resistance (HOMA-IR), a marker of insulin resistance, was not different among the groups. We conclude that compared with NGT subjects, elderly lean women with diabetes have impaired oral glucose-induced insulin secretion but have relatively preserved insulin sensitivity. This suggests that insulin resistance is not necessarily an essential component of Korean elderly lean diabetic women.

Advanced glycation end products induce apoptosis and procoagulant activity in cultured human umbilical vein endothelial cells.

Hyperglycemia and the late products of non-enzymatic glycosylation, called advanced glycation end products (AGEs), play an important role in the development of microvascular complications in diabetes mellitus. Previous studies have reported that a high glucose environment triggered apoptotic changes in human umbilical vein endothelial cells (HUVECs). Therefore, we investigated whether AGEs contribute to the development of apoptosis and prothrombotic activity in HUVECs. After incubation of HUVECs with 0.2, 2.2, 22, 220 and 2200 nM of AGE-bovine serum albumin (BSA) from 6 to 48 h, we assayed the degree of apoptosis and procoagulant activity (PCA). There were no significant differences between HUVECs cultured for 48 h with 0.2, 2.2 or 22 nM of AGE-BSA and in controls in the proportion of apoptotic cells (3.5 +/- 0.8%, 3.9 +/- 1.5% and 5.2 +/- 1.1% vs. 2.5 +/- 0.6%). However, the proportion of apoptotic cells increased significantly to 36.7 +/- 9.8% in 220 nM of AGE-BSA, and 72.3 +/- 10.2% in 2200 nM of AGE-BSA (P < 0.001). PCA levels were 142 +/- 10 s after 6 h of exposure to 22 nM (P < 0.01), 131 +/- 5 s after 6 h of exposure to 220 nM (P < 0.001), and 106 +/- 4 s after 6 h of exposure to 2200 nM of AGE-BSA (P < 0.001). These values show that PCA was shortened significantly from the basal value of 161 +/- 6 s, and remained below the basal level until the end of the study. The amount of tissue factor was also significantly increased in 22 and 220 nM of AGE-BSA compared to the controls. In conclusion, this study showed that AGEs could induce apoptosis and increase procoagulant activity in cultured HUVECs. We suggest that AGEs can contribute to the development of microvascular complications through cell death of HUVECs and functional changes of the blood vessels.

Ultrastructure of the larval tentacle and its skeletal muscle in Xenopus laevis.

During premetamorphic development, tadpoles of Xenopus laevis possess a transitory pair of long, slender, mobile tentacles situated at the corners of the mouth. Microscopic examination of the larval tentacle typically reveals three distinct compartments: a central core of cartilage, a laterally situated skeletal muscle, and a nerve supply medially. Along the length of each tentacle, the epidermis is supplied by many unmyelinated nerve fibers, presumably sensory in nature, which terminate as naked axons in close association with the epidermal cells. The striated tentacular muscle, in the proximal region of the lateral compartment, consists of extrafusal muscle fibers of varying size which range in number from 36 to 48 per tentacle (n = 10). Using morphometric criteria, we have classified the skeletal muscle fibers of the larval tentacular muscle into three types: large (30-50 microns), intermediate (20-30 microns), and small (10-20 microns). By electron microscopy, each type displays characteristic sarcomeric banding patterns, sarcotubular and mitochondrial disposition, and motor endplate ultrastructure. Our morphological observations indicate that the tentacles of the Xenopus tadpole are complex mobile facial extensions which may play roles in mechanoreception and/or chemoreception during the waterborne stages of development. Because of its transitory nature, the Xenopus tentacle may be a useful experimental model in future studies of neuromuscular development and subsequent regression in a relatively short period of time.

Ultrastructural evidence for intra- and extranuclear projections of GABAergic neurons of the suprachiasmatic nucleus.

GABAergic projections of the suprachiasmatic nucleus (SCN) were demonstrated in a double-labelling ultrastructural study which visualised the efferents of the SCN by PHA-L tracing, diaminobenzidine (DAB) immunocytochemistry, and GABA with immunogold postembedding staining. The results show a strong contralateral projection of the SCN that is partly GABA-containing. In addition, ipsilateral SCN projections to the dorsomedial hypothalamus and periventricular part of the paraventricular nucleus and sub-paraventricular nucleus were shown to contain GABA. The present results indicate that the SCN may utilize this inhibitory neurotransmitter to regulate and organize its own circadian rhythm as well as using GABA to transmit its diurnal information to other regions of the brain.

Projections of the suprachiasmatic nucleus to stress-related areas in the rat hypothalamus: a light and electron microscopic study.

The purpose of the present study was to investigate the sites in the hypothalamus where the suprachiasmatic nucleus (SCN) may influence corticosteroid secretion. In spite of the well established, SCN-mediated, daily rhythms in adrenocorticotrophic hormone (ACTH) and corticosteroid secretion, previous studies determining the projections of the suprachiasmatic nucleus failed to illustrate direct connections with corticotrophin-releasing hormone neurons (CRH). In order to identify where in the central nervous system the SCN may influence corticosteroid secretion, areas were selected that contained SCN efferents contacting neurons involved in the stress response. To achieve this in the present study, SCN efferents were visualized by Pha-L tract-tracing, together with the neurons involved in the stress response by immunocytochemical staining for c-fos protein. The sites where these efferents contacted c-fos-positive neurons were established by light microscopic double staining and electron microscopic immunocytochemical studies. It appeared that apart from the medial parvocellular area of the paraventricular nucleus (PVN) of the hypothalamus, many more regions showed fos-positive neurons. Sites where SCN efferents contacted such neurons are limited only to areas immediately adjacent to these putative CRH neurons but are not concentrated on these neurons themselves. These areas consist of the periventricular and rostral PVN together with the dorsomedial hypothalamus: all three regions are known to project into the PVN. Therefore, it is concluded that the SCN transmits its information related to corticosteroid secretion via interneurons in and around the PVN to the CRH-containing neurons, rather than by a direct interaction with these neurons themselves.

Suprachiasmatic nucleus lesion increases corticosterone secretion.

The diurnal rhythm of corticosteroid secretion is controlled by the suprachiasmatic nucleus (SCN). In rats, plasma corticosteroid levels rise just before the onset of the activity period during the dark phase. Our previous results indicated that vasopressin as a neurotransmitter from the SCN inhibited corticosteroid secretion in the area of the paraventricular/dorsomedial nucleus of the hypothalamus. We hypothesized that during the day the SCN may serve as an inhibitory system for corticosteroid secretion. To investigate this possibility, intact and SCN-lesioned animals were exposed to mild stress in the morning and evening and their plasma corticosteroid levels were monitored. The results indicate that SCN-lesioned animals have higher morning corticosteroid levels and respond both in the morning and evening with higher corticosteroid levels after stress than do intact control animals. We conclude, therefore, that these results indicate an inhibitory role of the SCN on corticosteroid secretion. The apparent discrepancy with the reported stimulatory role of the SCN on adrenocorticotropic hormone secretion is discussed.

Ultrastructural study of a blood-muscle spindle barrier after systemic administration of horseradish peroxidase.

The permeability of the normal muscle spindle capsule to the entrance of an exogenous protein tracer was assessed by the use of horseradish peroxidase (HRP). Adult mice were injected intravenously with a solution of HRP (MW 40,000). After varying intervals, ranging from two to 240 minutes, animals were perfused aortically with fixative, and anterior tibialis muscles were removed, processed, and examined. The results were evaluated by electron microscopic cytochemical techniques, and attention was directed to the movement of tracer and its relationship to the outer and inner capsule of the muscle spindle. HRP was first demonstrated in cytoplasmic vesicles crossing the continuous capillary endothelium supplying the muscle spindle, and was then detected in the interstitial space surrounding the outer capsule. In polar regions, HRP had entered the periaxial space by two minutes, and it was seen in cytoplasmic vesicles of the attenuated outer capsule. Later, HRP abutted the sarcolemma of intrafusal fibers, and by 12.5 minutes there was evidence of tracer in T-tubules of these muscle cells. Whereas at no time was tracer observed traversing any of the numerous intracellular junctions of the capsule, it appeared that polar regions were leaky and open-ended at their distal portions. The sensory equatorial zone was considerably less permeable to the entrance of tracer. Whereas HRP was visible intially in cytoplasmic vesicles of the subjacent capillary endothelium, it was not until 12.5 minutes that racer could be demonstrated within some vesicles of equatorial outer capsule cells. At later times, a small amount of HRP was observed in the equatorial periaxial space, where it was phagocytosed and finally sequestered by cells of the inner capsule as membrane-bound lysosomal deposits. Consequently, at no time was tracer incorported into either intrafusal fibers or their sensory nerve terminals. Thus, in contract to polar regions, the muscle spindle capsule in the equatorial zone appears to be effective in preventing the indiscriminate penetration of HRP from the bloodstream. This suggests dissimilar paths of tracer movement from the microvasculature into sensory and non-sensory regions of the muscle spindle.

An ultrastructural study of multifidus muscle in progressive idiopathic scoliosis. Changes resulting from a sarcolemmal defect at the myotendinous junction.

Biopsies of multifidus muscles were procured from patients with idiopathic scoliosis prior to Harrington rod instrumentation. Specimens from both convex and concave sides at the apex of the curve were examined by light and electron microscopy and compared with normal muscle samples. Abnormalities were detected on the concave aspect of the curve and the most dramatic morphological changes were noted at the myotendinous junction. Here a structural defect in the form of discontinuities in the sarcolemmal membranes of some muscle fibres was accompanied by large numbers of intimately-adhering connective tissue cells. Structural disorganization of the associated tendon occurred in conjunction with increased vascularization and with fatty cell and leukocyte infiltration. Further from the myotendon junction, structural lesions appeared more chronic and non-specific subsequent to the incipient sarcolemmal break in the affected muscle fibres. Hypertrophy, atrophy, centralization of nuclei, and disruption of sarcotubular and myofibrillar elements were noted in some muscle cells. While the aetiology of this disorder is unknown, a supposition is made that the primary change is an inherent weakness and subsequent break in the sarcolemma at the myotendon junction. This site is an important clue to the pathogenesis of this disease since it reflects morphological change in rapidly growing tissue occurring at the time of the rapid adolescent growth spurt leading to progression of the scoliotic curve.

Surface morphology of taste buds in catfish barbels.

External taste buds abound on barbels of the adult catfish Corydoras arcuatus. When examined by scanning electron microscopy, they are visualized as a series of punctate, conical elevations projecting from the general surface epithelium. All taste buds were found to be of one type. Both their external and internal surface features could be clearly elucidated on intact barbels and in barbels fractured transversely at various positions along their length. An extensive nerve terminal network penetrates the base of each taste bud. Two populations of elongated cells bearing prominent microvilli project through the central pore at the tip of each bud. One set of microvilli is thicker, longer and more club-shaped than its counterpart. While both are randomly distributed within each central pore, the small, short microvilli appear to outnumber the larger ones. A third population of cells, devoid of any apical microvilli, was also seen in some of the taste buds examined internally. These cells do not project to the external surface and are interpreted as "basal" cells described in previous light and transmission electron microscope studies of taste buds in other vertebrate species. The functional significance of some of these morphological findings is discussed.