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Biomedical subjects

E F Glasgow

Publications and source records attributed to E F Glasgow.

At least 19 recordsLinked to original sources

Minimally invasive subclavian/axillary artery to coronary artery bypass (SAXCAB): review and classification.

BACKGROUND AND PURPOSE: Subclavian/axillary artery to coronary artery bypass (SAXCAB) surgery is defined as a minimally (or less) invasive coronary revascularization procedure where one or more grafts are anastomosed to the second or third parts of the subclavian artery or any of the three parts of the axillary artery (inflow source) and attached to one or more coronary arteries, and where there are two separate minimally invasive incisions to expose the target coronary artery and the inflow sources, respectively. The indications and contraindications for SAXCAB surgery are discussed, and the relevant chest wall anatomy and that of the subclavian and axillary arteries are reviewed. The effect of respiration and anatomic variability as they impact the SAXCAB graft are discussed. Three components of the anatomy that are important in SAXCAB surgery are discussed: The relation of the first rib to the clavicle insofar as it affects access to the third part of the subclavian artery, the anatomy of the subclavian and axillary arteries and their branches, and the anatomy of the chest wall and its movement. In addition, the different SAXCAB variations that have been applied clinically are reviewed and classified, and future aspects of SAXCAB research are discussed. SAXCAB surgery is unique among the different types of minimally invasive direct coronary artery bypass (MIDCAB) surgery because of the enormous diversity of the techniques that have been described. Based on these descriptions, a new classification of SAXCAB grafting is proposed depending on whether the graft is inside or outside the rib cage and whether or not the coronary artery is exposed by rib resection or through an intercostal space. The third part of the classification takes into consideration the mode of entry into the chest, whether it is by rib resection or through an intercostal space. METHODS: Inquiries were made by telephone and by mail in the year 2000 to a number of surgeons who had published details of their SAXCAB techniques, and informal information was obtained by a series of personal communications as to the estimated number of operations they had performed and the outcomes. Published data was also used to formulate a rough guide as to the international status of the procedure at this time. RESULTS: The total estimated international experience is about 100 cases and the patency is between 70 and 100 percent in the time frame of about one to two years. CONCLUSIONS: The MIDCAB technique in general has been successful in providing an alternative way to revascularize the coronary arteries, and the SAXCAB has proved to be one of the most interesting classes of MIDCAB surgery. SAXCAB grafts seem to be unique among coronary revascularization procedures and, indeed, probably almost all vascular procedures, in that there is enormous diversity in the route for the graft from the inflow source to the target coronary artery. Being knowledgeable about the different varieties of SAXCAB surgeries will help the surgeon during a rescue operation as the surgery can be tailored to suit a particular patient. The SAXCAB seems to be a very safe operation, and it is striking that so far no one has reported any major complications.

Axillary Artery↗

The return of glomerular-filtered albumin to the rat renal vein.

BACKGROUND: Recent studies have demonstrated that the normal glomerular capillary wall (GCW) is not charge selective to albumin. This means that albumin flux across the GCW is high, and this has been confirmed in studies in which albumin uptake by the tubules has been inhibited. Therefore, there must be a high-capacity postglomerular retrieval pathway in normal kidneys that returns filtered albumin back to the blood supply. METHODS: This study identifies the presence of glomerular-filtered albumin in the renal vein from the analysis of the decrease of radioactivity in the venous effluent after the injection of a pulse of tritium-labeled albumin into the renal artery in vivo and in the isolated perfused kidney. RESULTS: The postglomerular filtered albumin is returned to the blood supply by a high-capacity pathway that transports this albumin at a rate of 1830 +/- 292 micrograms/min.rat kidney (N = 14, mean +/- SEM). This pathway has been identified under physiological conditions in vivo and in the isolated perfused kidney. The pathway is specific for albumin, as it does not occur for horseradish peroxidase. The pathway is inhibited in a nonfiltering kidney. The pathway is also inhibited by ammonium chloride (an agent that inhibits tubular protein uptake but does not alter glomerular size selectivity) and by albumin peptides (which compete for the tubular albumin receptor). CONCLUSIONS: The high-capacity retrieval pathway for albumin is most likely associated with transtubular cell transport. It is also apparent that most albuminuric states could be accounted for by the malfunctioning of this pathway without resorting to any change in glomerular permselectivity.

Albumins↗

Noninvasive discrimination of brachial plexus involvement in upper limb pain.

The ability of Elvey's "brachial plexus tension test" to identify pain referred from the cervical region was investigated in 50 patients with unilateral shoulder and upper arm pain: 25 reported symptoms commencing after open heart surgery, indicating a high probability of referred pain due to that procedure; 25 were athletes with injuries from throwing movements, a cause appearing much less likely to cause referred pain. Twenty-five asymptomatic subjects with no history of spinal or limb pain also were tested. Cervical and upper limb maneuvers of the test were assessed goniometrically. The cardiac group showed significantly greater test results than those of the other groups, suggesting that the test is able to discriminate referred and local sources of upper limb pain.

Adult↗

The inhibitory action of oxygen radical scavengers on proteinuria and glomerular heparan sulphate loss in the isolated perfused kidney.

The perfused isolated kidney is a partial ischemic system that is characterised by glomerular proteinuria and release of glomerular heparan sulfate. Metabolic changes associated with the levels of glutathione, xanthine oxidase and glyceraldehyde 3-dehydrogenase indicated that oxygen radical metabolites were being produced during the perfusion. We have demonstrated that a mixture of oxygen metabolite scavengers containing mannitol, superoxide dismutase and catalase included in the perfusion medium significantly reduced protein excretion. Similar results were obtained with the administration of allopurinol to the rat 24h prior to kidney removal and allopurinol in the perfusion medium. [35S]Heparan sulfate loss from the glomerulus was totally inhibited by the scavenger mixture. These results suggest that reactive oxygen metabolites may be involved in damage to renal capillaries, specifically to heparan sulfate proteoglycan, which leads to proteinuria as a result of partial ischemia produced during perfusion.

Animals↗

Ultrastructural immunoperoxidase investigations of human glomerular cells in tissue culture.

In order to elucidate the cells produced from human glomerular cultures, a pre-embedding ultrastructural immunoperoxidase technique was developed to investigate the precise localisation of a panel of monoclonal antibodies specific to human glomerular antigens in situ and used to identify the same antigens in vitro. The results obtained were correlated with the morphological features of the cells demonstrated by scanning electron microscopy. The study was able to show the presence of epithelial and mesangial cells in tissue culture, to confirm previous results indicating that glomerular endothelial cells are not present and to give some insight into the production of different basement membrane components by different cell types.

Antibodies, Monoclonal↗

Poststreptococcal glomerulonephritis in children: clinicopathological correlations and long-term prognosis.

Between 1962 and 1970, 36 children with acute biopsy-proven poststreptococcal glomerulonephritis (PSGN) entered a prospective long-term follow-up study. The initial biopsies were scored into four histological grades using criteria based on endocapillary proliferation, leucocyte infiltration, epithelial "hump" and crescent formation; 5 patients had grade-1 (least severe), 14 grade-2, 15 grade-3 and 2 grade-4 biopsies. Two children died from rapidly progressive glomerulonephritis; both had grade-4 biopsies. Early repeat biopsy in 12 patients showed improvement in all but one patient who progressed from grade 2 to type 2 mesangiocapillary glomerulonephritis (MCGN). The initial biopsy grade correlated significantly with heavy proteinuria (chi2 = 9.73, P less than 0.01) but not with hypertension, haematuria or renal functional impairment. Follow-up observations were made after mean periods of 9.5 years (range 5.4-12.4 years; 32 subjects) and 19.0 years (range 14.6-22 years; 30 subjects). None of the survivors had an abnormal plasma creatinine. Only one patient (grade-3 biopsy), a female with a subsequent history of recurrent pyelonephritis, was hypertensive. Isolated microscopic haematuria persisted in 1 grade-2 and 2 grade-3 subjects. One grade-2 subject had proteinuria secondary to MCGN and one grade-3 subject had mild proteinuria and borderline hypertension. Although 20% of subjects had urinary abnormalities, we conclude that the long-term outcome of PSGN in children is excellent.

Adolescent↗

The enhancement of aminonucleoside nephrosis by the co-administration of protamine.

An experimental model of focal segmental glomerular sclerosis (FSGS) was developed in rats by the combined administration of puromycin-aminonucleoside (AMNS) and protamine sulfate (PS). Male Sprague-Dawley rats, uninephrectomized three weeks before, received daily injections of subcutaneous AMNS (1 mg/100 g body wt) and intravenous PS (2 separated doses of 2.5 mg/100 g body wt) for four days. The series of injections were repeated another three times at 10 day intervals. The animals were sacrificed on days 24, 52, and 80. They developed nephrotic syndrome and finally renal failure. The time-course curve of creatinine clearance dropped and showed significant difference (P less than 0.01) from that of each control group, such as, AMNS alone, PS alone or saline injected. Their glomeruli showed changes of progressive FSGS. The ultrastructural studies in the initial stage revealed significant lack of particles of perfused ruthenium red on the lamina rara externa and marked changes in epithelial cell cytoplasm. Therefore, it is suggested that the administration of PS enhances the toxicity of AMNS on the glomerulus and readily produces progressive FSGS in rats resulting in the end-stage renal disease.

Animals↗

Biosynthesis of proteoglycans by isolated rabbit glomeruli.

Isolated rabbit glomeruli were incubated in vitro with 35SO4 in order to analyze the proteoglycans synthesized. Proteoglycans extracted with 4 M guanidine HCl from whole isolated glomeruli and from purified glomerular basement membrane (GBM) were analyzed by gel filtration chromatography. Two types of sulfated proteoglycans were found to be synthesized by rabbit glomeruli and these contained either heparan sulfate or chondroitin/dermatan sulfate glycosaminoglycan chains. These glycosaminoglycans were characterized by their sensitivity to selective degradation by nitrous acid or chondroitinase ABC, respectively. The major proteoglycan extracted from the whole glomeruli was a chondroitin/dermatan sulfate species (75%), while purified GBM contained mostly heparan sulfate (70%). The glycosaminoglycan chains were estimated to be about 12,000 molecular weight which is consistent with previous estimates for similar molecules extracted from the rat GBM.

Animals↗

Involvement of the macrophage in experimental chronic immune complex glomerulonephritis.

Serial renal biopsies for glomerular culture, histochemical staining for beta-glucuronidase, electron microscopy (EM) and light microscopy, were used to study macrophage involvement in experimental chronic immune complex (IC) glomerulonephritis (GN) induced in rabbits by daily intravenous injections of bovine serum albumin (BSA). In the 26 animals studied, proliferative GN of variable severity was induced, with mild disease in 5 animals, moderate proliferation in 15 and crescentic GN in 6. Macrophages first appeared in glomerular culture outgrowths during the 2nd and 3rd weeks, coincident with the onset of proteinuria and rising serum creatinine concentration. Large numbers of macrophages (in excess of 20 per glomerulus) were seen by the 5th weeks and persisted to the 9th week. The number of macrophages in outgrowths was not significantly greater in animals with crescentic disease. EM demonstrated macrophages in capillary loops, and in glomeruli with crescents, macrophages could be seen in the urinary space. Histochemical staining for beta-glucuronidase also demonstrated macrophages in the glomerular tuft and in crescents when present. These results indicate that macrophages constitute a considerable proportion of the glomerular hypercellularity seen in chronic IC glomerulonephritis.

Animals↗

Tissue culture of isolated glomeruli from patients with glomerulonephritis.

To study aspects of glomerular cell response in varying types of glomerulonephritis, we evaluated isolated glomeruli from 101 normal and diseased adult human renal biopsy specimens in tissue culture. Glomerular cell outgrowths from normal glomeruli consisted of large stellate cells (type I) and smaller fusiform cells (type II). A very occasional cell (type III), which had the features of a macrophage, was seen. The cellular outgrowth from isolated glomeruli reflected the numbers and types of cells present in the diseased glomeruli. Reduced numbers of cells were found in the outgrowth of sclerotic, hypocellular glomeruli. Glomeruli from biopsy specimens with altered morphologic appearances but no increase in cellularity (minimal change nephropathy, membranous nephropathy) produced the same growth pattern as from glomeruli isolated from normal kidneys. In mesangial proliferative nephritis, increased numbers of type II cells were detected in the outgrowth. Large numbers of macrophages were found in the glomerular outgrowth of patients with crescentic glomerulonephritis. Macrophages were absent when crescentic glomeruli were sclerosed, indicating the importance of macrophages in the acute hypercellular phase of crescent formation.

Culture Techniques↗

Histochemistry of glomerular cells in animal models of crescentic glomerulonephritis.

A histochemical enzyme profile has been used to determine the origin of the cells of glomerular crescents in rabbit and sheep models of rapidly progressive crescentic glomerulonephritis. Crescentic glomeruli were examined for beta-glucuronidase, esterase and acid phosphatase, the characteristic phagolysosomal enzymes of the monocyte-macrophage series and its transformed tissue counterpart, the epithelioid cell. More than 50% of the cells of the glomerular crescents of animals with experimental crescentic glomerulonephritis contained large amounts of all the enzymes, whereas the cells of normal glomeruli contained only trace amounts of acid phosphatase and esterase and no glucuronidase. These findings support the hypothesis that the major proportion of the cells of glomerular crescents are monocytes which have accumulated in Bowman's space rather than intrinsic glomerular cells which have proliferated.

Acid Phosphatase↗

The macrophage in the development of experimental crescentic glomerulonephritis. Studies using tissue culture and electron microscopy.

The role played by the macrophage in the development of injury in rabbit nephrotoxic nephritis (NTN) has been assessed by electron microscopy and glomerular culture of renal tissue obtained by several biopsies during the course of the disease. These observations have been correlated with the other immune, cellular, and biochemical events occurring in the glomerulus, ie, deposition of immunoglobulin and complement, proteinuria, polymorphonuclear leukocyte (PMN) exudation, fibrin deposition, crescent formation, and renal failure. A biphasic macrophage accumulation was detected, corresponding to the heterologous and autologous phases of the disease. In the autologous or crescentic phase, macrophages accumulated within the glomerular tuft from Day 5; their appearance coincided with the accumulation of PMN and development of proteinuria. Fibrin deposition in Bowman's space, which commenced on Days 6 and 7, was rapidly followed by the migration of macrophages from the glomeruli into Bowman's space. Within Bowman's space, macrophages were observed to phagocytose fibrin, transform into epithelioid and giant cells, and accumulate to form a substantial proportion of the cells forming the crescent. The inflammatory process of PMN exudation, macrophage accumulation, fibrin deposition, and crescent formation and the degree of renal failure reached a maximum by Days 12 to 14. Thereafter, resolution of the inflammatory process occurred so that by Day 40 macrophages had disappeared from the glomeruli. However, varying degrees of glomerular damage and renal failure persisted, occurring largely as a result of glomerulosclerosis and sclerosis of crescents. The tissue culture studies also demonstrated mesangial cell proliferation during the inflammatory process but did not show any abnormality of epithelial cell activity. This study demonstrates that the macrophages participate in NTN by accumulating in damaged glomeruli then migrating into Bowman's space (probably in response to fibrin deposition) where they undergo granulomatous transformation and accumulate, contributing to crescent formation.

Animals↗

The effect of defibrination on macrophage participation in rabbit nephrotoxic nephritis: studies using glomerular culture and electronmicroscopy.

Recent studies in experimental crescentic glomerulonephritis, using the technique of glomerular culture, have shown that the macrophage is a major cell type present within the glomeruli and developing crescents. It has been suggested that their accumulation is a consequence of glomerular fibrin deposition. The effect of defibrination with ancrod on the cellular events occurring in experimental crescentic glomerulonephritis in the rabbit was therefore assessed in this disease using the techniques of culture of isolated glomeruli, electronmicroscopy or renal tissue, and light microscopy. Defibrinated animals developed only minimal renal impairment, virtually no fibrin deposition in Bowman's Space and only a mild degree of crescent formation, in contrast to the severe renal failure, fibrin deposition and crescent formation that occurred in the untreated animals. The culture of isolated glomeruli and electronmicroscopy of intact renal tissue demonstrated large numbers of macrophages within and emerging from glomeruli of both defibrinated and untreated animals. However, only in untreated animals were macrophages seen to migrate into Bowman's Space, phagocytose fibrin, transform into epithelioid cells and accumulate to form crescents. These studies suggest that fibrin deposition in Bowman's Space is the major stimulus to the macrophage migration from capillary loops and accumulation in Bowman's Space. However, fibrin deposition does not appear to be the stimulus to macrophage accumulation within capillary loops as this event was not affected by defibrination.

Animals↗

Tissue culture of isolated glomeruli in experimental crescentic glomerulonephritis.

As a means of studying mechanisms of response to injury in glomerulonephritis, glomeruli from normal sheep and rabbits and from sheep and rabbits with experimental crescentic glomerulonephritis have been isolated and grown in tissue culture. The cellular outgrowths from the normal and diseased glomeruli have been compared. The outgrowth of glomeruli from normal animals contained only two cell populations whose microscopic and ultrastructural appearances were of epithelial and mesangial cells. The same cells were also observed in the outgrowths of glomeruli from animals with crescenti nephritis but in addition a third population of cells was present in large numbers. These cells were identified as macrophages by their mobility, ultrastructure, phagocytic capacity, and presence of Fc receptors. Glomerular outgrowth from sheep with crescentic glomerulonephritis contained 170 +/- 20 (SEM) macrophages and outgrowths from rabbits with crescentic nephritis contained 64 +/- 6 (SEM) macrophages per glomerulus. We have previously observed large numbers of macrophages in the outgrowth of isolated glomeruli from humans with rapidly progressive crescentic glomerulonephritis. The predominance of the macrophage in cultures of glomeruli from both human and animal crescentic glomerulonephritis suggests that this is an important cell in the inflammatory reaction occurring in crescentic glomerulonephritis and may comprise a substantial proportion of the cells forming the crescent.

Animals↗

Normal human glomerular cells in culture.

Reproducible patterns of cell outgrowth have been observed from isolated normal adult, human glomeruli grown in tissue culture. Three morphologically distinct cell populations designated Types I, II, and III have been observed in culture from 15 normal human kidneys. Assessment of the morphology and behaviour of these cells has been made by phase contrast, time-lapse cinemicroscopic, transmission and scanning electron microscopic examination. The phagocytic capacity of these cells has been determined. The Type I cell appears in culture by migration from the capillary loops, its branched cytoplasm and ultrastructural features confirming its origin as a visceral epithelial cell. In keeping with the highly specialised nature of this cell, division was rare, movement was not observed, and differentiation was progressively lost in culture. The Type II cell was mobile and capable of active division. Ultrastructural features were those of mesangial cells. The Type III cell which was seen only rarely, had the features of a macrophage. Endothelial outgrowth was not observed.

Adult↗

Cell characteristics of cultured glomeruli from different animal species.

A modified sieving technique has been developed to isolate pure glomeruli from monkey, sheep, dog, rabbit and rat kidney. Glomeruli from all these species have been grown in tissue culture and the glomerular cell outgrowth studied by light microscopy and time-lapse cinemicroscopy. The pattern of growth was the same for all the species studied. In all species, three cell populations have been identified with the features of epithelial cells, mesangial cells and macrophages, although the latter population is only rarely observed. The morphology and culture characteristics of each cell type in all species were similar, including the relative numbers present and rates of division.

Animals↗