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Biomedical subjects

S Bachmann

Publications and source records attributed to S Bachmann.

At least 19 recordsLinked to original sources
PubMed1992

Warm Carolina rinse solution prevents graft failure from storage injury after orthotopic rat liver transplantation with arterialization.

An injury to nonparenchymal cells, characterized by loss of viability of sinusoidal endothelial cells and activation of Kupffer cells, occurs after reperfusion of livers stored for transplantation. Recently, a new solution, Carolina rinse solution, was shown to prevent reperfusion injury to endothelial cells in vitro almost completely and to improve graft survival after orthotopic rat liver transplantation (ORLT) without arterialization. ORLT with arterialization permits longer cold storage of donor livers and more closely models human surgery. Therefore, we evaluated the effects of Carolina rinse solution on graft survival after ORLT with arterialization in syngeneic Lewis rats. Just prior to implantation, donor livers stored in University of Wisconsin (UW) solution were rinsed with 30 ml of Ringer's solution, saline, or Carolina rinse solution at 1 degree-4 degrees C. In livers stored for 15 h and rinsed with Ringer's or saline solution, long-term graft survival was only 8%. Using Carolina rinse solution containing 1 mmol and 200 mumol adenosine per liter, graft survival improved to 40% and 80%, respectively. Graft survival did not improve when using Carolina rinse solution with adenosine omitted or Ringer's solution containing 200 mumol adenosine per liter. Livers were also rinsed with Carolina rinse solution containing 200 mumol adenosine per liter at 28 degrees-30 degrees C rather than at 1 degree-4 degrees C. With warm Carolina rinse solution, survival improved further to 100%, 80%, and 50% after 15, 18, and 21 h of storage. After 18 h of storage, light and electron microscopy demonstrated marked denudation of the sinusoidal lining and activation of Kupffer cells in grafts rinsed with Ringer's solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1992

Peritoneal morphology in children treated by continuous ambulatory peritoneal dialysis.

Fifty peritoneal biopsies (PB) from 35 patients with end-stage renal disease, treated by continuous ambulatory peritoneal dialysis (CAPD) and aged 2 months to 18 years, were examined by light microscopy (n = 50) and/or scanning electron microscopy. PB were performed during surgical procedures immediately before the start of, during, or after the cessation of CAPD treatment. PB from 15 children without renal disease undergoing laparatomy were examined similarly. Before the start of CAPD, a scarcity and shortening of the mesothelial microvilli was observed by scanning electron microscopy. During and after CAPD, variable alterations of mesothelium, interstitium and capillaries were found. The mesothelial layer was absent in all 5 PB obtained during episodes of active peritonitis. In patients treated by CAPD for longer than 6 months, mesothelial denudation was observed more frequently (6/11) than in children treated for shorter periods (1/7) (P < 0.08). Fibrosis of the peritoneal membrane was present in about 50% of patients during or after the cessation of CAPD without impairment of peritoneal function. No correlation was found between the presence of fibrosis and the frequency of peritonitis or the duration of CAPD treatment.

Adolescent↗
PubMed1992

Expression of nitric oxide synthase in kidney macula densa cells.

The distribution of nitric oxide synthase (NOS), the enzyme by which NO is generated from L-arginine, was investigated in rat kidney. The indirect immunofluorescence technique using a polyclonal antibody against type I NOS was applied, followed by the histochemical NADPH diaphorase staining technique on the same sections in order to demonstrate the enzymatic activity of NOS. Macula densa cells were strongly stained by both techniques, demonstrating abundant NOS in the cytoplasm of these cells. In addition, these findings were confirmed by nonradioactive in situ hybridization, thus demonstrating the corresponding messenger RNA in macula densa cells as well. Our findings provide the morphological basis for a possible role of NO as a mediator substance in signal transfer from distal tubular fluid to glomerular arterioles.

Amino Acid Oxidoreductases↗
PubMed1992

Transgenic rats carrying the mouse renin gene--morphological characterization of a low-renin hypertension model.

Transgenic rats [TGR; strain name TGR(mRen2)27] harboring the mouse Ren-2 renin gene have been recently generated as a model for the study of primary hypertension that offers the advantage of a clearly-defined genetic alteration. Expression of the mouse Ren-2 gene causes severe hypertension (200 to 260 mm Hg) which is responsive to converting enzyme inhibitors. Compared to control transgene-negative littermates, plasma renin and angiotensin II values are lowered in TGR, whereas plasma prorenin values are strongly elevated. The adrenal gland in TGR shows marked overexpression of mouse renin messenger RNA; in situ hybridization using a 35S-labelled mouse-renin RNA probe reveals that enhanced renin expression is mainly localized to cells of the zona glomerulosa and outer zona fasciculata. Immunohistochemically, renin protein in the TGR adrenal gland is stored in larger quantities than in controls. Adrenal transgene expression probably accounts for most of the elevated plasma prorenin level in TGR, since bilateral adrenalectomy (ADX) causes a significant decrease in prorenin level (318 +/- 79 ng angiotensin I/ml/hr before ADX to 70 +/- 43 ng 4 days after ADX, P less than 0.0005). In the kidney, renin synthesis is almost completely suppressed in TGR. In situ hybridization demonstrates that few juxtaglomerular afferent arterioles express renin. Immunohistochemically, the TGR kidney shows significantly reduced renin and angiotensin II immunoreactivity at the afferent arteriole. Ultrastructural analysis of the afferent arteriolar wall frequently shows the complete absence of renin secretory granules since the granular cells are mostly converted into smooth muscle cells. Beginning at an age of approximately four to six months, TGR develop hypertension-related alterations and pathological lesions in various tissues. In the kidney, the wall thickness of arterioles and arteries is strongly increased, and glomerular lesions including different stages of sclerosis are observed. The thoracic aorta displays a considerable increase in tunica media thickness due to both myocyte hypertrophy and interstitial fibrosis. Coronary arteries and arterioles of the heart are thickened and perivascular fibrosis is observed. The data show that TGR(mRen2)27 transgenic rats display all typical characteristics of hypertensive pathology, making them an interesting model for therapeutic interventions. The fact that these changes occur in animals with a single gene difference to normotensive rats makes them a particularly suitable model for studies on gene-related hypertensive processes.

Adrenal Glands↗
PubMed1992

Histological and immunocytochemical characterization of Coxiella burnetii-associated lesions in the murine uterus and placenta.

The fetoplacental units and the postgravid uterus of BALB/cJ (H-2d) mice inoculated intraperitoneally with Coxiella burnetii (Nine Mile isolate, phase I) on day 6 of pregnancy were examined histologically and immunocytochemically at 1 to 160 days postinoculation. Clinically, abortions, stillbirths, and perinatal deaths were observed. Histological lesions in the placenta were characterized by severe necrosis of the decidua basalis and the labyrinth, fibrinoid degeneration of decidual vessels, and microthrombosis. Pyometra and endometritis at the sites of previous placental attachment, characterized by ulceration, central necrosis, and moderate cellular infiltration consisting of neutrophils and macrophages, were observed postpartum. Pups sacrificed at the age of 9 days exhibited interstitial pneumonia with few granulomas and granulomatous hepatitis and splenitis. Immunocytochemically, antigen-bearing cells were first detected in the decidua 9 days postconception, and single immunopositive cells were detected in the fetal placenta 4 days later. Thereafter, until abortion or parturition, abundant accumulation of C. burnetii antigen was observed in the maternal and fetal compartments of the placenta. Up to 28 days postinoculation, many immunopositive cells were demonstrated at the sites of previous placental attachment, whereas the adjacent endometrium contained only a few antigen-positive cells. C. burnetii antigen was demonstrated in decidual cells, trophoblasts, and macrophages and extracellularly within the sinuses of the labyrinth and in the uterine lumen but not in granulated metrial gland cells. Fetuses in utero and aborted, stillborn, or perinatally dying offspring were immunocytochemically negative for C. burnetii antigen; however, pups killed 9 days after birth showed lesion-associated positive immunoreaction in the lung, liver, and spleen. The present study shows that infection with C. burnetii during pregnancy results in uncontrolled growth of the organism in the murine uteroplacental unit and that associated lesions are characterized by necrosis of placental tissues, fibrinoid degeneration of decidual vessels, and microthrombosis.

Animals↗
PubMed1990

Tamm-Horsfall protein-mRNA synthesis is localized to the thick ascending limb of Henle's loop in rat kidney.

Tamm-Horsfall protein (THP) has been previously detected in cells of the thick ascending limb of Henle's loop (TAL) of different mammalian species using immunocytochemical methods. A nearly complete identity between THP and uromodulin, an immunosuppressive glycoprotein present in the urine of pregnant females, has been established recently. This paper describes the cellular location of THP mRNA by high-resolution in situ hybridization using a [35S]-labeled human uromodulin cRNA (antisense-) probe of a length of 665 base pairs. Control experiments were performed using an mRNA (sense-) probe of the same length. The probe was hybridized to frozen sections of the rat kidney. THP mRNA distribution in the kidney was found to be homologous to the immunocytochemical labeling pattern: Autoradiographic signal was present along the entire length of the TAL including the post-macula segment which leads to the distal convoluted tubule. Tubular cells of the macula densa were negative. Labeling intensity of the TAL epithelium was found to increase from the origin of the TAL at the transition between inner and outer medulla to its end beyond the macula densa. Labeling of the medullary segment in the inner stripe was weak, whereas outer medullary and cortical segments very strongly expressed THP mRNA. The glomerulus, the portions of the nephron proximal to the TAL, the distal convoluted tubule as well as the collecting duct system were negative.

Animals↗
PubMed1990

Effect of water intake on the progression of chronic renal failure in the 5/6 nephrectomized rat.

This study tests the possible influence of the urinary concentrating process and/or of vasopressin (AVP) on the progression of early chronic renal failure (CRF). Male Sprague-Dawley rats were submitted to 5/6 nephrectomy and were offered water ad libitum throughout the study. In addition, half of the rats (high water intake, HWI) received their food mixed with a water-rich agar gel. The other rats (normal water intake, NWI) ate the same amount of food plus agar in the usual dry powder form. This resulted in doubling the daily water ingestion in HWI. Renal function was studied for 10 wk and kidney morphology assessed thereafter. Increased water intake in HWI reduced solute-free water reabsorption and urine osmolality about threefold to 12 +/- 1 ml/day and 390 +/- 9 mosmol/kgH2O, respectively (week 5 as example). Hematocrit, plasma sodium, and plasma creatinine concentration were unchanged. The progressive increases in urinary protein excretion and in systolic blood pressure observed in this model of CRF were significantly slowed in HWI compared with NWI (at week 5, 8.6 +/- 1.8 vs. 23.1 +/- 6.2 mg protein/day and 142 +/- 8 vs. 167 +/- 10 mmHg, respectively). Remnant kidney weight per unit body weight was 21% lower in HWI than in NWI (P less than 0.02). Incidence of glomerulosclerosis was also reduced and was correlated with kidney weight (P less than 0.01). AVP plasma level (PAVP) and plasma renin activity (PRA) were measured in additional rats. PAVP was about twofold higher (P less than 0.05) and PRA twofold lower (P less than 0.001) in rats with 5/6 nephrectomy than in control rats with two kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1988

Effect of irradiation and storage on patulin disappearance and some chemical constituents of apple juice concentrate.

The effect of irradiation on the patulin content and on the chemical composition of apple juice concentrate during storage at 4 degrees C over a period of several weeks was investigated. The radiation-induced disappearance of the mycotoxin in relation to the absorbed dose followed an exponential relationship. The radiation dose (D50), i.e., the dose which reduced the patulin content to 50% of its initial value was equal to 0.35 kGy. Storage of the irradiated concentrate had no effect on the patulin content; however, storage did lead to a slight increase in the titratable acidity and a decrease in the amounts of the carbonyl compounds and the ascorbic acid concentration. The development of non-enzymatic browning during storage of the irradiated samples followed the same kinetics as that of the non-irradiated samples.

Ascorbic Acid↗
PubMed1987

Microheterogeneity of the collecting duct system in rabbit kidney as revealed by monoclonal antibodies.

This report describes the immunolocalization of three monoclonal antibodies along the collecting duct system in rabbit kidney. The antibodies were raised against antigens derived from a membrane fraction of homogenized papillary tissue. Western Blot analysis demonstrated that each of the antibodies recognized a single band of about 190,000 (PCD1), 210,000 (PCD2) and 50,000 (PCD3) daltons. In renal tissue, the antibodies bound specifically to the epithelia of the connecting tubule (CNT), the collecting duct (CD) and the papillary surface epithelium. Differences in the binding patterns of the antisera were limited to the cortex. PCD1 labeled only a few scattered cells in the CNT, and exhibited a heterogeneous binding along the cortical collecting duct (CCD). PCD2 and PCD3 binding patterns were similar. In the CNT, these antibodies bound to the intercalated cells (IC-cells) but not to the CNT-cells proper. In the CCD, both IC-cells and principal cells were labeled. The binding to the medullary collecting duct by all three antisera was identical. The ureter was labeled only by PCD2 and PCD3, and none of the antisera bound to the bladder epithelium. The antibody binding patterns provide information concerning tubular axial heterogeneity and embryogenetic aspects of the CNT and the CCD. These antibodies may be used as differentiation markers in studies of the developing kidney and of renal tissue culture systems.

Animals↗
PubMed1987

Electron-microscopic immunogold localization of a collecting-duct antigen (PCD2) in intercalated and principal cells of rabbit kidney.

A monoclonal antibody against an antigen (PCD2) derived from the rabbit renal papilla recognized principal and intercalated cells of the collecting duct system in the adult rabbit kidney. Intercalated cells were heterogeneous in the connecting tubule and the cortical collecting duct, where immunoreactive and unreactive cells were shown to coexist. In the outer medullary collecting duct, all intercalated cells exhibited PCD2-immunoreactivity. Connecting tubule cells proper were not recognized by the antibody, whereas all principal cells of the collecting duct revealed specific immunoreactivity. The immunocytochemical heterogeneity of the intercalated cells is discussed in terms of a functional heterogeneity. Cytologically, the immunogold labeling of principal and intercalated cells was shown to occur along the plasmalemma, in the intracellular membrane structures and along the Golgi transport route. This pattern suggests that the antigenic determinant, which is ubiquitous in both principal and reactive intercalated cells, belongs to a membrane protein.

Animals↗
PubMed1985

Ultrastructural localization of Tamm-Horsfall glycoprotein (THP) in rat kidney as revealed by protein A-gold immunocytochemistry.

The present study describes the intracellular distribution of Tamm-Horsfall protein (THP) in rat kidney. The localization was determined by immunoelectron microscopy using the protein A-gold technique. Various fixation and embedding protocols were evaluated for this purpose. Brief perfusion fixation (3 min) with 1% glutaraldehyde and embedding in a highly hydrophilic glycol methacrylate-polyester mixture were most appropriate for antigen-antibody recognition and structural preservation. The overall tissue distribution of THP was evaluated by indirect immunofluorescence microscopy; reaction was strong along the entire thick ascending limb of the loop of Henle (TAL) with enhanced fluorescence in the apical cytoplasm. On the electron microscopic level immunogold labelling was concentrated over numerous membrane-bound vesicles which form a compartment in the apical cytoplasm. The Golgi region was consistently labelled, whereas the plasma membranes revealed only sporadic labelling at the luminal side, and basolateral membranes were mostly unlabelled. Quantitative evaluation of the gold labelling, which was separately done for the inner stripe, outer stripe and cortical TAL, consistently showed the highest particle density in the apical cytoplasm. Middle and basal levels in the TAL cells were only moderately labelled. The results are discussed with respect to the current opinion which describes THP as a membrane glycoprotein. We speculate that the accumulation of THP in the apical vesicular compartment of TAL cells indicates a storage site of the protein, possibly prior to extrusion via exocytosis of the vesicle contents.

Animals↗
PubMed1985

Pre- and postglomerular arterioles of the kidney.

Characteristics of the structural organization of the afferent and efferent glomerular arterioles of the mammalian kidney, that have so far escaped adequate functional discussion, include: presence and distribution of myoendothelial junctions in afferent and efferent arterioles and their possible functional relevance as stretch receptors; distribution of smooth-muscle cells around cortical efferent arterioles and, in particular, the presence of a contractile segment at the beginning of the efferent arterioles; elaboration of a basement membrane-like material beneath the endothelium of efferent arterioles and the continuity of this material with the mesangial and extramesangial matrix material; and structural organization of the endothelium of juxtamedullary efferent arterioles, consisting of up to 30 longitudinally arranged endothelial cells, and its possible functional significance.

Animals↗
PubMed1985

Structural adaptation of the distal convoluted tubule to prolonged furosemide treatment.

Rats were treated with furosemide, continuously applied by implanted minipumps, for 6 days. As compensation for the salt lost with the urine the animals drank large amounts of a salt solution ad libitum. This procedure resulted in an enlargement of kidney cortex. Light and electron microscopic studies revealed a proliferation of the distal convoluted tubule (DCT). The proportion of the DCT in the cortical tissue increased from 5.98 +/- 1.3% in controls to 9.54 +/- 1.7% (P less than 0.01) in treated rats. Basolateral cell membrane amplification in DCT cells increased from 17.33 +/- 2.9 to 38.24 +/- 5.8 (P less than 0.0001) in treated rats, while luminal membrane area per unit tubular length did not change. The structural changes after furosemide treatment in the DCT suggest an increase in active transcellular transport capacity of this segment. It is assumed that the chronically altered Na load of the tubular fluid (due to transport inhibition in the thick ascending limb of Henle's loop) delivered to the DCT may specifically stimulate the transport capacity of this segment by augmentation of basolateral cell membrane area. The changes occurring in the segment situated downstream to the one in which the function is impaired by furosemide emphasize the role of tubular fluid composition in the regulation of transport function.

Animals↗
PubMed1984

Immunohistochemical localization of a protein fraction derived from rabbit renal papilla.

Studies were carried out to define antigenic characteristics of the rabbit renal collecting duct. Renal papillae of adult rabbits were homogenized, centrifuged, and the 600 X g pellet was extracted with 0.5% Triton X-100 in the presence of 1 M NaCl. The crude extract was fractionated on an anion exchange column (DEAE cellulose). A fraction enriched in acidic proteins that co-purified with a radioactive 150 kd glycoprotein from cultured collecting duct cells (Minuth 1982), was used for immunization of guinea pigs. The antiserum shows the following characteristics as revealed by indirect immunofluorescence on the rabbit kidney: 1) Among all tubular epithelial cells only principal cells of the collecting duct and the connecting tubule cell show immunoreactivity. 2) The antiserum decorates the epithelial-interstitial interface of the whole collecting duct as well as of connecting tubule and thick ascending limb of Henle's loop. 3) There is immunoreactivity of interstitial fibers throughout the kidney. 4) Epithelial cells in a variety of other organs in rabbit did not react with the antiserum. Our data demonstrate an antigenic distinction of both, the connecting tubule cell and the principal cell, discriminating these cells from other tubular epithelial cells including the intercalated cells of the collecting duct system. Furthermore, our findings point to a heterogeneity along the distal nephron with respect to the constituents of the epithelial-interstitial interface.

Animals↗
PubMed1984

Immunocytochemical localization of a renal glycoprotein (gpCDI) synthesized by cultured collecting duct cells.

A sulfated, proline-rich glycoprotein (gpCDI, apparent molecular weight 200,000 in column chromatography and 150,000 in SDS-PAGE) was isolated from cultured renal collecting duct epithelium by centrifugation. Triton X100 extraction and DEAE-cellulose ion exchange chromatography. A DEAE-cellulose ion exchange chromatography fraction with the enriched gpCDI was used for immunization of guinea pigs. The antiserum was prepared for antigen localization by indirect immunofluorescence in collecting duct cell cultures and in tissue sections of neonatal and adult rabbit kidneys. In the cultured collecting duct epithelium, antibody staining of the epithelium and structures of the extracellular matrix was age dependent. Cultures of dedifferentiated collecting duct monolayers revealed positive reaction in the cytoplasm. In neonatal and adult rabbit kidneys, the antibody was localized in the entire collecting duct system but not in the collecting duct ampullae of the newborn kidney. Staining of the cytoplasm was found only in medullary collecting ducts of the neonatal kidney; other portions revealed staining mostly at the basal circumference of the tubule and at the luminal cell borders. Apart from collecting ducts, no other tubular segments were reactive. The cortical and the medullary interstitium contained fluorescent fibres which were concentrated around vascular structures. A possible relation between gpCDI and collagenous compounds is discussed. Bowman's capsule reacted positively, whereas staining of the mesangial matrix was weak. The localization of the antigen, as revealed by indirect immunofluorescence, suggests that gpCDI occurs both in intracellular and extracellular (interstitial) location. Two main points are emphasized: Firstly gpCDI is considered an important constituent in different stages of collecting duct development, and secondly, the staining pattern of the antibody varies with the different portions of both young and adult kidney collecting ducts; this staining heterogeneity may correspond with the known regional differences of collecting duct functions.

Animals↗
PubMed1984

Multicystic transformation of kidneys in chronic renal failure.

With real-time sonography, 120 nondialyzed uremic patients prior to hemodialysis, 108 patients on maintenance hemodialysis and 9 patients postdialysis after successful homotransplantation were examined for the presence of renal cysts. Even in incipient renal failure, multiple cysts were demonstrable in some patients (at a serum creatinine of 3 mg/dl in 22% of patients), particularly in patients with analgesic nephropathy. When hemodialysis was started (serum creatinine approximately 10 mg/dl), 35% of the patients had multiple cysts. On hemodialysis, the prevalence, number and size of cysts rose progressively with time. After 8 years of hemodialysis, 92% of the patients had multiple cysts. However, enlargement of the kidneys was observed in only 2/108 patients. No major clinical complications were noted with the possible exception of 1 case of renal cell carcinoma. No correlation was noted between hematocrit and presence or extent of cystic transformation, but the 2 patients with cystic enlargement of the kidneys were polyglobulic. In 8/9 patients after transplantation, cysts were demonstrable in the patient's own kidneys after a median follow-up of 16 months. On light microscopy, cysts were lined by cuboidal or columnar epithelial cells with frequent papillary or adenomatous proliferations. The cyst lumen was filled with amorphous or lamellated organic material, which exhibited microfibrillar structure on electron microscopy. One kidney examined after ex vivo perfusion fixation showed multiple interconnected cavities on scanning electron microscopy. Ultrastructural studies showed epithelia with either the characteristics of proximal tubular cells (i.e. numerous microvilli, interdigitations and abundant lysosomes or mitochondria) or distal tubular cells (i.e. highly interdigitating processes) or finally collecting duct cells (i.e. no interdigitations and few microvilli).

Acute Kidney Injury↗