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Biomedical subjects

S Bachmann

Publications and source records attributed to S Bachmann.

122 records · Page 7Linked to original sources
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↗
PubMed1983

Effects of thermal therapy on rehabilitation after total knee arthroplasty. A prospective randomized study.

The role of local heat or cold therapy used in conjunction with exercise in the rehabilitation of total knee arthroplasty patients was investigated. Thirty-six osteoarthritic patients were analyzed. Parameters evaluated were range of motion, swelling about the knee, and pain. All patients received the total condylar knee prosthesis and began range of motion rehabilitation fourteen days after operation. Results showed that temperature alteration does not augment passive range of motion after total knee arthroplasty. It was also shown that cold application decreases swelling as compared with heat. Additionally, the application of cold partially alleviates the discomfort of the rehabilitation process in certain patients.

Aged↗
PubMed1982

Histotopography and ultrastructure of the thin limbs of the loop of Henle in the hamster.

In the kidney of the Syrian hamster the descending thin limbs of both the short and long loops of Henle are not spatially separated from each other and descend between the vascular bundles. Ultrastructurally, five different epithelial types are distinguished in the thin limbs of the short and long loops of Henle. Short loops possess only a descending thin limb with a simply organized epithelium (type 1). Long loops comprise an upper and a lower part of the descending thin limb and the ascending thin limb. The upper part of the long descending thin limb is equipped with a complex and highly interdigitating epithelium with shallow junctions (type 2), which gradually transforms into the simple noninterdigitating type-3 epithelium of the lower part. In a minor portion of long descending thin limbs, however, the upper part begins with an even more complexly organized epithelium (type 2a) than type 2. Type-2a epithelium is conspicuously thicker and possesses a more elaborate mode of cellular interdigitation. Along the descent of this tubular part through the inner stripe of the outer medulla, type-2a epithelium transforms into type-2 epithelium. It is suggested that the long descending thin limbs, which start with type-2a epithelium, belong to the longest loops. The type-4 epithelium of the ascending thin limbs is characterized by flat and extensively interdigitating cells with shallow junctions. The unique pattern of the type-2a epithelium favors the assumption that solute secretion essentially contributes to the increase in concentration of tubular fluid in long descending thin limbs.

Animals↗
PubMed1980

Phagocytes in the axial complex of the sea urchin, Sphaerechinus granularis (Lam.). Fine structure and x-ray microanalysis.

In the axial complex of Sphaerechinus granularis intense phagocytotic activity is encountered. The phagocytes ingest morula cells and other phagocytes; a lysosomal digestion of the phagocytosed cells is suggested. A subdivision into early and late phagocytes is made according to their granular content. Most of the phagocytes possess intranuclear crystalloids that exhibit a filamentous or particulate substructure. Late stages of phagocytes filled with residual bodies and crystalloids leave the axial complex via the lacunar system to be removed through the rectum. X-ray microanalysis reveals a constant presence of iron and sulphur in the crystalloids. The residual bodies contain iron, sulphur, calcium and zinc in varying amounts. This study confirms that one function of the axial complex is excretion.

Animals↗
PubMed1978

Ultrastructural, fluorescence microscopic and microfluorimetric study of the innervation of the axial complex in the sea urchin, Sphaerechinus granularis (lam.).

In juxtaposition with the contractile epithelia of the axial complex of the sea urchin, Sphaerechinus granularis, several types of nerve fibers with different vesicle populations were determined. Nerve terminals, filled with clear vesicles and dense core vesicles, form synaptoid neuromuscular junctions. Close to the somatocoelic epithelia of the axial and terminal sinus septa, numerous axon profiles form a nerve plexus. Among the epithelial cells covering the plexus, two types of nerve cells can be distinguished which presumably produce neurosecretory and aminergic granules, respectively. Monoamine fluorescence (formaldehyde-induced fluorescence, Falck-Hillarp technique) was analyzed microspectrofluorimetrically. The emission spectrum of the fluorophores occurring in the present material shows a maximum at 475 nm and is characteristic of catecholamines; the excitation maximum at 380 nm after formaldehyde treatment is typical of catecholamines at low pH only. Since the peak ratio (370:320 nm) does not change after HCl-vapor treatment, the fluorophores are likely to be indicative of dopamine.

Animals↗
PubMed1978

Fine structure of the axial complex of Sphaerechinus granularis (Lam.) (Echinodermata: Echinoidea).

Three regions of the axial complex in Sphaerechinus granularis can be distinguished: 1) The axial organ which protrudes from one side of the axial sinus; the sinus septum which separates the sinus from the body cavity and encloses the stone canal; the pulsating vessel which runs along the inside of the axial organ. 2) The blindly-ending terminal sinus in which the pulsating vessel broadens out to the contractile terminal process. 3) The ampulla of the stone canal which connects the axocoel and water vascular system and which opens out through the madreporite. A single-layered, monociliated coelomic epithelium surrounds all regions of the axial complex. This epithelium contains smooth muscle cells at the contractile areas. Canaliculi, surrounded by basal lamina, are formed through infolding of epithelia; they end blindly in the fluid- and connective tissue-matrix of the inner structures. The lacunae of the dorso-ventral mesentery connect the periesophageal and the perianal haemal ring with the axial organ. The axial organ contains many coelomocytes rich in pigment and granules. These coelomocytes are separated into compartments by elastic fibres. Phagocytosis of whole cells and transformational stages of coelomocytes suggest storage and degradation functions. An excretory function via the water vascular system is also suggested.

Animals↗
PubMed1971

[Amalgams].

Explore the source record for details and available documents.

Dental Amalgam↗
PubMedDate not supplied

Tamm-Horsfall protein excretion during chronic alterations in urinary concentration and protein intake in the rat.

Tamm-Horsfall protein (THP), a normal constituent of mammalian urine, has been determined in rat urine under various conditions in an attempt to elucidate the physiological role of this glycoprotein. Experiments were designed to assess whether THP production is related to the process of urine concentration or to the transport activity of the thick ascending limb of the loop of Henle (TAL), the nephron segment where it is produced. For this purpose, THP excretion was measured, by radioimmunoassay, in adult male rats under 4 different conditions induced by the following chronic treatments: (1) furosemide (12 mg/day in osmotic minipumps); (2) increased water intake; (3) antidiuretic hormone (ADH) infusion (50 ng DDAVP/day in osmotic minipumps) in rats of the Brattleboro strain with hereditary hypothalamic diabetes insipidus; (4) high-protein (32% casein) versus low-protein diet (10% casein). Each experiment included 6 experimental and 6 control rats. After treatment for 1-3 weeks, 24-h urines were collected for determination of urine flow rate, osmolality, and creatinine and THP concentrations. No significant changes in THP excretion were observed in experiments (1) and (2) despite 5- to 7-fold-differences in urine flow rate. Antidiuretic hormone treatment in (3) slightly lowered THP excretion (287 +/- 53 vs. 367 +/- 41 micrograms/day per 100 g body weight; p less than 0.005), whereas high-protein diet, in experiment (4), led to a 50% increase in THP excretion (446 +/- 57 vs. 304 +/- 79 micrograms/day per 100 g body weight; p less than 0.001). Expressing THP excretion relative to that of creatine did not change these findings. These results show (1) that chronically established changes in the level of diuresis, chronic furosemide-induced blockade of the Na,K,Cl-cotransporter or the absence of ADH in Brattleboro rats have little or no impact on the level of THP production, and (2) that THP production is independent of the intensity of transport in the TAL, since two conditions which both are known to increase the transport rate of solutes in the TAL (ADH infusion and high-protein diet), resulted in opposite changes in THP excretion. It is concluded that the rate of THP synthesis is neither linked to the process of urine concentration nor to the ion transport activity of the TAL.

Animals↗
PubMedDate not supplied

Focal overexpression of collagen IV characterizes the initiation of epithelial changes in polycystic kidney disease.

Changes of extracellular matrix are involved in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). The relationship between epithelial changes and extracellular matrix production was studied in a new rat model (Han:SPRD/cy+) at an early phase of cystogenesis. Messenger RNA expression of the alpha 1(IV)-chain of collagen type IV, the main structural component of basement membrane, was localized by in situ hybridization. The presence of collagen IV-protein was shown by immunohistochemistry. At an initial stage, cysts were lined with normal-appearing epithelium except for focal zones of less differentiated cells exhibiting strong collagen alpha 1(IV) mRNA expression and a thickened basement membrane. In these zones, an increase in cell number (2.39-fold) per unit epithelial area indicated hyperplastic growth. Conspicuously, these zones were found at 'bottleneck'-like transitions from normal-size tubules to cystic expansions. Intermediate stages of cysts showed more prominent extracellular matrix deposits and an overall maximally enhanced collagen IV mRNA expression, whereas terminal stages were lined with a flat, simplified epithelium and exhibited moderate collagen IV expression. We suggest that focally enhanced expression of collagen IV in the tubular epithelium and surrounding interstitium of Han:SPRD/cy+ rat kidney is initially involved in cyst development.

Animals↗
PubMedDate not supplied

Zonal expression of angiotensin II-AT1-receptor genes in rat kidneys.

This study aimed to examine the relative distribution of ANGII-AT1-receptor gene expression in different zones of the rat kidney, namely the glomeruli, cortex (CO), outer and inner stripes of outer medulla (OSOM and ISOM, respectively) and inner medulla (IM). By RNAse protection we found a ratio for the overall abundance of AT1 mRNA of 1, 0.68, 0.52, 0.86 and 0.46 for glomeruli, CO, OSOM, ISOM and IM, respectively. The intrazonal proportion of AT1a and AT1b mRNA was determined by RT-PCR, which yielded values for the ratio AT1a/AT1b of 1.1, 4.7, 4.4, 3.7 and 1.9 for glomeruli, CO, OSOM, ISOM, and IM, respectively. These findings suggest a zonal heterogeneity in the expression of AT1-receptor genes such that the highest expression is found in glomeruli and ISOM, whilst the papilla shows the lowest level of expression. Moreover, there appears to exist a corticopapillary gradient for the relative expression of AT1a and AT1b-receptor genes such that the preponderance of AT1a-receptor gene expression decreases into a papillary direction. Within the CO glomeruli appear as an isle of AT1b receptors of relatively high expression.

Animals↗