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Biomedical subjects

K Langer

Publications and source records attributed to K Langer.

At least 37 records · Page 2Linked to original sources
PubMed1996

Ultrastructural study of the dermal microvasculature in patients undergoing retrograde intravenous pressure infusions.

BACKGROUND: Retrograde intravenous pressure infusion (RIPI) of drugs, e.g. antibiotics, under arterial occlusion (Bier's block) allows high local tissue concentrations in the extremities. This technique is of particular value in the antibiotic treatment of infected diabetic foot lesions. OBJECTIVE: The aim of our study was to look for morphological changes of the dermal microvasculature induced by RIPI. METHODS: In 7 patients with infected diabetic foot lesions, punch biopsies were taken from the calf skin before and at the end of RIPI and studied by light and electron microscopy. RESULTS: RIPI induced a dilatation of venous capillaries and postcapillary venules, loosening of contacts between endothelial cells (EC) with focal formation of small gaps in the vessel wall and a widening of the space between EC and pericytes. Lymphatic vessels were markedly dilated. In contrast, arterioles did not exhibit signs of morphological alteration. RIPI did not produce cellular damage of blood and lymphatic vessels. CONCLUSIONS: The morphological changes of dermal vessels induced by RIPI are presumably due to a rapid rise in venous pressure. Our morphological observations support results of previous hemodynamic and nuclear medical investigations, which showed that RIPI enhances the filtration and diffusion of molecules into the interstitium, leading to high local tissue concentrations. The venous capillaries and postcapillary venules are involved in this process in particular.

Aged↗
PubMed1995

Expression of MHC class II antigens on rat bone marrow cells and macrophages, and their modulation during culture with murine GM-CSF or M-CSF.

Flow cytometric analysis employing MRC OX 6 and MRC OX17 monoclonal antibodies recognizing determinants on RT1.B or RT1.D molecules, equivalent to murine I-A and I-E, respectively, was used to detect rat MHC class II antigen (Ag) expression. Approximately 5% of freshly isolated rat bone marrow cells (BMC) expressed RT1.B and over 30% displayed RT1.D molecules. The RT1.D+ cells were W3/13+, OX 7+, OX 19- and OX 22-. After one week culture of BMC with murine recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF), regardless of concentrations, 90 to 95% of the cells were scored as bone marrow-derived macrophages (BMDM phi), and over 30% expressed both RT1.B and RT1.D Ag. GM-CSF increases the percentage of BMDM phi bearing MHC class II Ag in a concentration-dependent manner. This effect seems to be specific because antibodies to interferon-gamma, tumor necrosis factor-alpha or interleukin-4 did not reduce the number of cells expressing RT1.B and RT1.D Ag. Furthermore, GM-CSF was able to trigger expression of class II molecules on rat peritoneal macrophages (M phi) and BMDM phi resulted from cultures of BMC with mouse M phi-CSF (M-CSF), and the RT1.B and RT1.D inducing effect of GM-CSF was opposed by M-CSF, and by anti-GM-CSF antibodies. The induction of MHC class II Ag synthesis by GM-CSF on rat BMDM phi was confirmed at the mRNA level by Northern blot analysis employing cDNA probes encoding the RT1.B alpha.

Animals↗
PubMed1995

Hyperhomocysteinemia and the risk for vascular disease in hemodialysis patients.

The objective of this study was to examine if hyperhomocysteinemia is associated with occlusive vascular disease in hemodialysis patients. The study design included risk factor analysis and determination of serum homocysteine in hemodialysis patients. Fifty chronic uremic patients on regular hemodialysis treatment were studied. Twenty-four patients had coronary, cerebral, or peripheral signs of occlusive vascular disease. Cerebral vascular disease was diagnosed by computed tomography, arterial angiography, or Doppler sonography of the carotid and vertebral arteries. Coronary vascular disease was diagnosed by documented history of myocardial infarction or by coronary angiography. The diagnosis of peripheral vascular disease was established by angiography of the lower limb arteries. In all control patients, Doppler sonography of the carotid, vertebral, and lower limb arteries and thallium-201 exercise imaging were without pathologic results. Measurements included blood pressure, body mass index, smoking behavior, serum homocysteine (measured by gas chromatography/mass spectrometry), serum total, low-density lipoprotein, and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides, and plasma fibrinogen. In a stepwise multiple logistic regression analysis, high serum homocysteine was significantly associated with occlusive arterial disease (R = 0.23; P = 0.031). Furthermore, hypertension (R = 0.18; P = 0.058), but not serum total, low-density lipoprotein, and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides, diabetes mellitus, body mass index, plasma fibrinogen, and smoking behavior, was significantly associated with atherosclerosis. Our results support the hypothesis that hyperhomocysteinemia is an independent risk factor for vascular disease in hemodialysis patients.

Adult↗
PubMed1994

Pigmented clear cell acanthoma.

We present five cases of macroscopically pigmented clear cell acanthomas. Masson-Fontana silver stain revealed dendritic melanocytes containing melanin granules in large numbers interspersed among the tumoral keratinocytes. The dendritic cells expressed S-100 protein. Electromicroscopy, performed on one pigmented clear cell acanthoma, showed melanosomes in large numbers in the dendrites of melanocytes; whereas only a few melanosomes were found in the adjacent keratinocytes, indicating a disturbed melanin transfer. We propose the name "pigmented clear cell acanthoma" for this variant of Degos' acanthoma.

Adult↗
PubMed1992

Hyperkeratosis lenticularis perstans (Flegel's disease). Ultrastructural study of lesional and perilesional skin and therapeutic trial of topical tretinoin versus 5-fluorouracil.

Lesional and perilesional skin samples from a 57-year-old man who had hyperkeratosis lenticularis perstans (HLP) (Flegel's disease) were studied by light and electron microscopic examination. Keratohyalin granules were diminished at the center of a fully-developed lesion. In contrast, keratohyalin appeared normal and membrane-coating granules were found in reduced numbers at the edges of the HLP lesion and were easily detected in normal numbers in clinically normal, perilesional skin. The inflammatory infiltrate in the HLP lesion was composed of small lymphocytes, which often displayed nuclei with deep infoldings resembling Sézary cells, and larger histiocytic cells, many of which were in close contact with the lymphocytes. Peripheral blood mononuclear cells did not show an abnormal ultrastructural appearance. Treatment with topical 5-fluorouracil cream led to the disappearance of the HLP lesions, whereas topical tretinoin was ineffective.

Administration, Cutaneous↗
PubMed1992

A new central supply system as alternative source for bicarbonate dialysate.

Bicarbonate dialysis is mandatory for high efficiency treatment. In most cases bicarbonate is delivered either as prepacked powder or as a stable liquid concentrate in 6-10 I plastic containers. With a newly designed central supply system (CSS) using 800 I tanks of custom-made sterile and pyrogen free concentrates, we investigated the risk of bacterial contamination of dialysate in a 30-bed dialysis unit. During three months, samples of reverse osmosis (RO) water, concentrates and dialysate were taken every two weeks. Colony forming units (CFU) were counted after 48 h incubation. Further samples were taken during nine months of continuous use of the CSS without further intermittent disinfection. None of the samples had greater than 10/ml CFU. Pseudomonas, corynebacteria and enterobacter were the predominant species. In summary, this CSS proved reliable in providing bacteriologically safe bicarbonate dialysate as defined by international standards (CFU less than 200/ml). It significantly reduces costs, workload and environmental pollution by plastic waste.

Bacteria↗
PubMed1991

[Collodion baby with transition to mild lamellar ichthyosis.Clinical course, histopathology and ultrastructural findings].

The case of a collodion baby in whom the condition evolved into a mild form of lamellar ichthyosis is presented. The clinical course was impressive: the hard, collodion-like horny membrane started to crack soon after the birth and had detached completely at the 9th day of life; after a few more days, almost complete clearing of the skin had occurred. At the age of 10 months, the child had only a very mild lamellar ichthyosis. Whereas light microscopy revealed only compact hyperkeratosis on the 1st day of life, electron microscopy suggested a favourable prognosis even at this early stage, which has been corroborated by the ensuing clinical course.

Dermatologic Agents↗
PubMed1990

[Long-term results following kidney transplantation. An empirical analysis of 467 allogeneic kidney transplants concerning the effect of clinical and immunological variables on graft function].

In a homogeneous group of 467 cadaver kidney transplants performed within one single center between 1979 and 1987, we analysed the influence of main risk factors on long-term survival up to 72 months. Calculating survival rates by Kaplan-Meier actuarial methods the overall graft survival exceeded 71%. The corresponding patient survival was higher than 90%. A good HLA-A-B and DR match was of significant positive influence. Patients who received cyclosporine had a significant better outcome compared to conventional immunosuppressive therapy. A marked advantage was demonstrated for such variables as number of pretransplant blood transfusions, number of rejection episodes, preservation time and renal function as measured by plasma creatinine. Independently age was a main risk factor for curtailed graft survival. Although immunological factors accounted for more than 45% of transplant loss we found a surprisingly high percentage of infections (36%). Vascular problems or technical failure were below 10%. We conclude that a profound clinical examination in the pretransplant period is of high value and remains necessary to identify high risk patients in the long range.

Adolescent↗
PubMed1990

The ultrastructure of dysplastic naevi: comparison with superficial spreading melanoma and common naevocellular naevi.

Eleven dysplastic melanocytic naevi with various degrees of dysplasia, as judged by light microscopy, were studied by transmission electron microscopy, and their intra-epidermal melanocytes compared with those of five superficial spreading melanomas and seven common benign naevocellular naevi. Intra-epidermal melanocytes in dysplastic naevi exhibited signs of cellular atypia, which were most pronounced in the dysplastic naevi with histological high-grade dysplasia. A correlation between the degree of dysplasia at the light microscopic level and the degree of cytological atypia at the ultrastructural level was noted, and melanocytes in dysplastic naevi with a high degree of dysplasia had ultrastructural features similar to the melanocytes in superficial spreading melanomas. Our observations support the concept that dysplastic naevi fill the biological gap between benign naevocellular naevi and malignant melanomas and suggest that at least some of the dysplastic naevi must be regarded as potential precursor lesions of malignant melanoma, particularly those exhibiting a high degree of histological dysplasia.

Adult↗
PubMed1990

Cyclosporin A in combination with photochemotherapy (PUVA) in the treatment of psoriasis.

Forty patients with relapsing plaque psoriasis involving more than 20% body surface were treated either with cyclosporin A (CyA) plus PUVA or the retinoid etretinate plus PUVA (RePUVA). They initially received either CyA (2 weeks) or etretinate (1 week) alone and then PUVA was given concomitantly until complete remission. The patients were monitored over a period of 6 months and any relapse recorded. With each combined treatment regimen, CyA plus PUVA and RePUVA, the patients cleared within comparable periods of time (mean treatment period of 5.3 vs. 4.7 weeks after initiation of therapy and 3.3 vs. 3.7 weeks after initiation of PUVA). However, the cumulative UVA dose required for clearance (110.9 J/cm2 vs. 62.1 J/cm2 (P less than 0.05)) and the incidence of severe and early relapses were significantly higher in the CyA cohort. Within 6 months severe relapses had occurred in 58% of CyA plus PUVA but only in 15% of RePUVA-treated patients (P less than 0.001). This suggests that the CyA plus PUVA regimen as performed in this study is less effective than RePUVA.

Adult↗
PubMed1990

Keratitis, ichthyosis and deafness (KID)-syndrome: report of three cases and a review of the literature.

We report three patients with keratitis, ichthyosis and deafness (KID)-syndrome. All had characteristic hyperkeratotic skin lesions and neurosensory hearing defects. Two had ophthalmologic symptoms. The third patient did not have eye involvement at the age of 3 years, but exhibited the other typical signs of the syndrome. In none of the three cases were any of the patients' relatives affected, and a spontaneous new mutation is the most likely explanation for the occurrence of this rare syndrome. Histopathological and electron microscopic studies revealed orthohyperkeratosis but no other pathology and no abnormal deposits of glycogen were found. Treatment with the aromatic retinoid etretinate proved to be of little value in any of the patients. The necessity for early audiologic and ophthalmologic evaluation and the need for life-long medical care for patients with KID-syndrome is emphasized.

Adult↗
PubMed1990

Congenital melanocytic nevi with halo phenomenon: report of two cases and a review of the literature.

Verrucous congenital nevocellular nevi surrounded by a depigmented halo occurring in a 7-year-old boy and a 13-year-old girl were excised and the wounds closed primarily. Histopathologic studies revealed a striking arrangement of the inflammatory infiltrate in these halo nevi. A dense, band-like, lymphohistiocytic infiltrate was found only around and intermingled with A- and B-type nevomelanocytes in the upper dermis, whereas inflammatory infiltrates were completely absent from type C-nevomelanocytes in the lower parts of the reticular dermis. The literature is reviewed with particular consideration of congenital halo nevi.

Adolescent↗
PubMed1990

A low-protein diet protects uremic rats against the negative sequelae of metabolic acidosis.

Metabolic acidosis is a common finding in uremia. The metabolic consequences, however, are poorly understood. Thus, the aim of our study was to assess the effect of chronic metabolic acidosis in 5/6-nephrectomized male Sprague-Dawley rats given a normal (18%; n = 19) and a low-protein diet (8%; n = 23). Each of these groups was sequentially given CaCO3 and CaCl2 in the drinking water for a fortnight each. The animals were randomly assigned to start either with CaCO3 or CaCl2 (random cross-over design). The blood pH decreased significantly in both CaCl2 groups (18% protein: CaCO3 7.18 vs. CaCl2 7.11; 8% protein: CaCO3 7.26 vs. CaCl2 7.09) as did standardized base excess (18% protein: CaCO3-5.9 vs. CaCl2-9.7; 8% protein: CaCO3-3.6 vs. CaCl2-12.6). Food intake declined during acidosis in both groups, but more in the 18% protein group. The same occurred with body weight (g) in the 18% group, which decreased dramatically (8% protein: CaCO3 389 vs. CaCl2 390; 18% protein: CaCO3 413 vs. CaCl2 366). The change in body weight was reflected in the urinary urea excretion (mg/24 h/g food) (8% protein: CaCO3 0.9 vs. CaCl2 1.0; 18% protein: CaCO3 2.2 vs. CaCl2 30.8). There was a significant increase in proteinuria (mg/24 h) in the 8% group (CaCO3 10 vs. CaCl2 15), while in the 18% group no real change occurred (CaCO3 24 vs. CaCl2 18). Factoring the proteinuria for food intake, however, also resulted in a tendency towards an increased proteinuria in the 18% group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗