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Biomedical subjects

K M Koch

Publications and source records attributed to K M Koch.

At least 19 recordsLinked to original sources
PubMed1992

Lack of clinical evidence for a specific HIV-associated glomerulopathy in 203 patients with HIV infection.

Several authors described a high incidence of proteinuria with frequent progression to nephrotic syndrome and/or renal failure in patients with HIV infection. Though renal histological changes were rather non-specific, the existence of a specific, HIV-associated glomerulopathy was postulated. We repeatedly investigated proteinuria and serum creatinine in 203 HIV-infected patients. One hundred and twenty-two patients (group 1) had early stages of the disease without opportunistic infections, 81 suffered from acute opportunistic infections (group 2). In patients with a positive qualitative test (Combistix), quantitative measurement (Biuret) for proteinuria was carried out; when proteinuria was greater than 0.5 g/24 h, SDS gel electrophoresis was performed. None of the patients of group 1 had a proteinuria greater than 0.5 g/24 h or an elevated serum creatinine. Eleven of 81 patients from group 2 had a proteinuria between 0.5 and 3 g/24 h; one further patient of group 2 developed a transient proteinuria of 7.7 g/24 h. Only three of the proteinuric patients showed a glomerular pattern in SDS gel electrophoresis, all three during acute CMV or EBV infections. Fourteen of 81 group 2 patients showed a transient elevation of serum creatinine (x +/- SD of the maximum serum creatinines: 225.3 +/- 163 mumol/l), most during pentamidine therapy for Pneumocystis carinii infection; one patient treated with high-dose acyclovir had to be temporarily dialysed. In the investigated 203 HIV patients no nephrotic syndrome and no sustained elevation of serum creatinine greater than 200 mumol/l was observed. All cases of proteinuria and elevation of serum creatinine were associated with severe opportunistic infections and the administration of potentially nephrotoxic antibiotics.

Adolescent↗
PubMed1992

Present status of kidney transplantation.

Kidney transplantation today is the method of choice to treat end-stage renal disease (ESRD) in more than 50% of the ESRD-population. Due to major improvements in surgical handling, immunosuppressive therapy, and infection control, the one-year survival for patients and first grafts has reached nearly 90% in the recent years. In contrast no comparable achievements have been made in long-term graft survival. A constant number of grafts is lost yearly after the first postoperative year. In addition an increasing number of well functioning grafts is lost due to the death of the recipients caused mainly by cardiovascular and malignant disorders. The extension of kidney transplantation to all suitable recipients is nearly exclusively hampered by the organ shortage, which is further enhanced by failing grafts. This urges us to further improve the prognosis for patient and graft. This must include organ sharing on the basis of improved HLA-typing to achieve highly compatible grafts. The tools for differential diagnosis of acute and chronic graft dysfunction have to be improved. New immunosuppressive agents with higher immunosuppressive power and specificity but fewer nephrotoxic, metabolic and hemodynamic side effects are required at least for chronic rejection. The risk of infectious and malignant complications must be limited.

Cadaver↗
PubMed1979

[Role of erythropoietin deficiency in the pathogenesis of renal anemia].

A review is given of clinical studies performed by use of a highly sensitive in-vitro erythropoietin assay (fetal mouse livercell culture) in large patients' populations to clarify the controversial role of erythropoietin deficiency in the pathogenesis of renal anemia. Studies involved a.) patients with chronic renal disease and varying degree of renal insufficiency in the predialysis phase b.) non-nephrectomized and anephric patients on regular hemodialysis treatment. The data available demonstrate that the initial phase of renal anemia is accompanied by a compensatory increase of serumerythropoietin concentration and therefore erythropoietin deficiency has to be excluded as a primary cause of the anemia of renal failure; merely a relative lack of erythropoietin seems to exist. In the terminal phase of renal failure, erythropoietin deficiency becomes absolute, such in 50% of the investigated non-nephrectomized hemodialysis patients and in all anephric patients. However in individual patients even in terminal renal failure a sustained regulatory feedback mechanism between serumerythropoietin concentration and hematocrit, probably working at lower hematocrit level, could be demonstrated.

Anemia↗
PubMed1979

Haemolysis due to formaldehyde-induced anti-N-like antibodies in haemodialysis patients.

During reuse of formaldehyde sterilized Kiil-dialysers, red cell survival, measured by means of 51Cr t/2, was significantly reduced (p less than 0.001) in 16 patients with anti-N-like positive sera, when compared with 19 antibody negative control patients (mean +/- SD: 16.5 +/- 2.7 versus 22.4 +/- 3.1 days.) In antibody negative patients (n = 10) replacement of formaldehyde sterilized dialysers by ethylene-oxide sterilized disposable dialysers resulted in a significant increase (p less than 0.002) of 51Cr t/2 (Mean +/- SD, days: Kiildialyser 16.3 +/- 1.9; disposable dialyser 20.3 +/- 3.5). This improvement took place, although antibody titres persisted during the 51Cr-measurements and declined thereafter only slowly. In antibody negative patients (n = 6) red cell survival did not increase, when formaldehyde as a sterilant was avoided. In antibody positive patients mean haematocrit rose significantly (p less than 0.05), whereas in none of the antibody negative patients a definite change of haematocrit occurred. The data demonstrate, that formaldehyde sterilisation of dialysers may cause antibody-mediated haemolysis contributing to the extent of renal anaemia. This immunohaemolysis may be corrected, in spite of continuing antibody persistance, when formaldehyde exposure is totally avoided, or possibly when minimized.

Antibody Formation↗
PubMed1979

Serum erythropoietin concentration in chronic renal failure: relationship to degree of anemia and excretory renal function.

By use of the fetal mouse liver cell assay, serum erythropoietin (SEp) concentration was measured in 135 patients at various stages of chronic renal failure and in 59 healthy subjects. In patients with creatinine clearances (CCr) ranging from 2 to 40 ml/min/1.73 sq m, endocrine renal function was found to deteriorate in parallel to excretory renal function. The known negative correlation between SEp and hematocrit (Hct) was not apparent, probably because of the loss of renal mass accompanying progress of anemia and renal insufficiency. In contrast, in patients with minimal variation of residual excretory renal function, as in individual patients investigated repeatedly within a short period of time, changes of Hct were always accompanied by opposite changes of corresponding SEp concentrations. Thus, patients with chronic renal failure have a sustained regulatory feedback mechanism between Hct and SEp, which probably works at a lower level.

Adolescent↗
PubMed1978

[Haemodialysis in the treatment of biguanide-induced lactate acidosis (author's transl)].

Severe lactate acidosis developed in nine diabetics on biguanide. When lactate acidosis was diagnosed all patients had reduced renal function, six being oligoanuric. Pre-existing chronic renal failure as a factor in the development of lactic acidosis was excluded in five patients, normal renal function being restored later. All patients were dialysed, seven surviving. This mortality rate is lower than that reported by others for biguanide-induced lactate acidosis. Rapid biguanide elimination by dialysis was demonstrated both in vitro and in vivo. The in vivo clearance of buformin was 83 +/- 43 ml/min (mean +/- SD, n = 4), that of phenformin 68 +/- 33 ml/min (n = 7). The main advantages of haemodialysis in the treatment of biguanide-induced lactic acidosis are rapid removal of toxic biguanides and excess lactate and the ability to administer sodium bicarbonate adequately without risking hypernatraemia and fluid overload.

Acidosis↗
PubMed1978

Serum erythropoietin concentration in anephric patients.

In 13 bilateral nephrectomized patients serum erythropoietin (SEp) activity could be measured quantitatively by use of the highly sensitive fetal mouse liver cell assay. SEp concentration in the majority of the cases was below the mean of normal controls. There was a significant positive correlation between SEp levels and hematocrits, suggesting erythropoietin (Ep) deficiency to be a causative factor in the anemia of the anephric state. Androgen therapy stimulated extrarenal Ep production in all of 5 anephric patients studied.

Adolescent↗
PubMed1978

[Recurrent hyperparathyroidism following subtotal parathyroidectomy].

Recurrent hyperparathyreoidism occurred in 3 of 9 patients in terminal renal failure from 9 months to 2 years after an initially successful subtotal parathyroidectomy. In all cases we find temporary remission of clinical signs of hyperparathyreoidism after surgery. Our clinical experience provided by followup in these patients showed an insufficient biochemical and clinical control. We find recurrence in 3 cases and repeat neck exploration was indicated for 2 patients.

Humans↗
PubMed1978

Serum erythropoietin measurements using the fetal mouse liver cell culture: the importance of reduction of variation in the specific activity of radioiron--transferrin.

Because of varying iron--transferrin concentrations in different serum samples, and varying test serum portions within the culture, variations of the radioiron--transferrin/total iron--transferrin ratio are inevitable, when serum erythropoietin (Ep) concentrations are measured using the fetal mouse liver cell assay. It could be demonstrated that radioiron uptake is directly proportional to the specific activity of radioiron--transferrin, when the latter varies over the range which is inherent to the method. Variations of the ratio of radioiron--transferrin/total iron--transferrin were reduced by preincubating radioiron with human transferrin, and by minimizing the test serum portion of the culture. With this modified in vitro bioassay, serum Ep concentrations of 59 healthy subjects were measured. Mean serum Ep concentration was 136 +/- 66 (s.d.) mU/ml.

Animals↗
PubMed1978

[Morphological aspects of parathyroid gland transplantation. Contribution on the clinical relevance of induced, invasive tissue growth].

The results of morphologic studies performed in 18 patients who had total parathyroidectomy and autotransplantation of parathyroid tissue into the forearm muscle are presented. All patients had long-standing renal disease with azotemia, hyperphosphatemia and high levels of parathyroid hormone. The histologic findings after total parathyroidectomy, before gland transplantation, are important for selection of parathyroid tissue for surgery. Diffuse hyperplasia with the development of multiple nodules of the parathyroids can possibly be adverse for the transplant. In one case, nine month after autotransplantation we found a tumor in the forearm, measuring 2.0 X 3.0 X 2.2 cm in diameter. Morphologic findings in this case before implantation showed diffuse hyperplasia with adenomatous nodules but no signs of carcinoma. The grafted parathyroid tissue after excision was seen with blood vessel invasion in the normal skeletal muscle. In the case of primary renal disease with secondary parathyroid hyperplasia, the light microscopic examination revealed an autonomous tumorlike adenomatous formation in the autografted parathyroid tissue, with graft-dependent hypercalcemia. The invasive growth with some signs of neoplasia following autotransplantation raises the question of the development of certain neoplasia.

Adult↗
PubMed1978

Comparison of haemodialysis (HD) and post dilution haemofiltration (HF) on an unselected dialysis population.

In a comparison of post-dilution haemofiltration (HF) with routine haemodialysis (HD) HF was found to be technically feasible and without difficulty a method of treating end-stage renal failure patients. HF offers the theoretical benefit of a high removal rate of middle molecules at the expense of measured small molecule clearances. The reported improvement in blood pressure and hyperphosphataemia in HF could not be found in our unselected population. The better tolerance to fluid removal during HF may be due to the linear weight loss during treatment but cannot be attributed to constancy in serum osmolality HF (3 X 20-23L ultrafiltrate/week) seems to be an adequate treatment for small patients. In large, heavy patients without significant residual renal function the ultrafiltration volume has to be increased in relation to body weight. HF was found to be superior to HD in patients with fluid removal problems and frequent hypotensive episodes during HD.

Adolescent↗
PubMed1978

Sustained negative feedback between haematocrit and serum erythropoietin concentration in end-stage renal failure.

In a longitudinal study the individual values of serum erythropoietin (SEp) in end-stage renal failure were investigated in 15 patients. SEp was determined by use of the foetal mouse liver cell assay on three occasions: (A) 2--6 months before the onset of RDT, (B) on day of first dialysis, and (C) 2--6 months following the onset of RDT. In every patient SEp increased from (A) to (B), and decreased again from (B) to (C). Changes of haematocrit were exactly opposite to changes of SEp. The results demonstrate that even in the terminal stage of chronic renal failure erythropoietin production is stimulated or suppressed in response to variations in the degree of anaemia.

Adult↗
PubMed1978

Total parathyroidectomy with autograft of parathyroid tissue in treatment of secondary hyperparathyroidism.

In 16 patients with severe symptomatic hyperparathyroidism reduction of hyperplastic parathyroid mass was performed by total parathyroidectomy with autotransplantation of parathyroid tissue. In all patients except one serum parathormone (PTH) levels returned to normal and postoperative difficulties in calcium homeostasis were rarely observed. Fifteen patients had normal PTH levels after surgery. Graft function was proven in 10 cases, but in 5 cases graft function could not be definitely established with the methods applied. One graft failure was observed. Total parathyroidectomy with autotransplanation of parathyroid tissue is recommended as the treatment of choice when surgical correction of secondary hyperparathyroidism is necessary.

Adult↗
PubMed1977

The variable role of erythropoietin deficiency in the pathogenesis of dialysis anaemia.

To evaluate the role of reduced erythropoietin (Ep) production in the pathogenesis of dialysis anaemia, measurements of serum erythropoietin (SEp) concentration by means of a highly sensitive in vitro bioassay were performed in 88 non-nephrectomised non-transfused regular haemodialysis patients. In 50 patients (group 1) SEp levels were lower than 120 mU/ml. In the remaining 38 patients (group 2) SEp concentrations ranged from 120-369 mU/ml. Group 1 showed a highly significant positive correlation between SEp concentration and haematocrit as did 13 anephric patients investigated for comparison. In contrast, group 2 displayed a highly significant negative correlation between SEp concentration and haematocrit. The results demonstrate the existence of two distinctive groups of similar size in regular haemodialysis patients: those with an absolute (group 1) and those with a relative deficiency of Ep (group 2). In the case of the latter, lack of Ep is probably a secondary factor in the pathogenesis of anaemia, whereas uraemic toxicity and blood loss may play a primary role.

Anemia↗