[Chronic granulomatosis: a rare differential diagnosis in liver granulomas in adulthood]

A now 43-year-old man was known since childhood to have mesenteric and subcutaneous lymphadenopathy. Histological examination of liver biopsies and excision of some lymph nodes when an adult showed epithelioid granulomas, in places with Langhans giant cells. Diagnostic splenectomy revealed no pathological findings. His present admission to hospital was for an infection with high fever. On auscultation moist rales were audible over the apex of the left lung. The chest radiography showed pneumonic infiltration. Blood culture grew Pseudomonas aeruginosa. Ultrasound demonstrated hypoechogenic homogeneous and smoothly circumscribed round foci in the liver hilus and around the coeliac trunk. The upper lobe pneumonia healed under antibiotic treatment. As chronic granulomatosis was suspected, the nitroblue tetrazolium and superoxide production tests were performed. They demonstrated that the capacity of the granulocytes to form oxygen radicals was markedly diminished. Chronic granulomatosis is an inherited disorder of granulocyte function linked to the X-chromosome. It must be included in the differential diagnosis of any unclear granulomatous disease even in adults.

[Incidence of ultrasound detectable liver hematomas after ultrasound controlled fine needle puncture with the 0.95 mm cutting biopsy cannula in comparison with percutaneous liver biopsy with the 1.4 mm Menghini needle]

BACKGROUND

Recently, a high incidence of ultrasound-detected hepatic hematomas due to percutaneous liver biopsy has been reported. Until yet, little is known about the incidence of asymptomatic hepatic hematomas following sonographically guided fine-needle biopsy.

PATIENTS AND METHODS

For that reason, we carried out a prospective study with sonographic examinations before and after liver biopsy in 160 patients. 51 patients, aged 50 to 83, median 67 years, with focal liver lesions had ultrasound-guided liver biopsy using the 0.95 mm-cut biopsy-needle, in 109 patients (17 to 80, median 49 years) with diffuse liver disease percutaneous liver biopsy with the 1.4 mm-needle of Menghini was performed.

RESULT

After fine-needle biopsy none of the 51 patients with focal liver lesions displayed liver hematoma on ultrasonography. In the group of patients who underwent percutaneous Menghini biopsy a liver hematoma, sized up to 12 x 5 cm in diameter, occurred four times (3.7%).

CONCLUSION

The results of this study indicate that fine-needle biopsy of the liver is a particularly safe diagnostic procedure, when compared with percutaneous Menghini biopsy.

Prospective study of the incidence of ultrasound-detected hepatic hematomas due to percutaneous Menghini needle liver biopsy and laparoscopy-guided Silverman needle biopsy

Recently, a high incidence of sonographically detected hepatic hematomas following percutaneous liver biopsy and laparoscopy-guided liver biopsy has been reported. For this reason a prospective study in 178 patients was performed. The patients were examined by ultrasound before and 24 hours after percutaneous liver biopsy using the 1.4 mm-Menghini needle (n = 107) and by laparoscopically-guided biopsy with the 2.5 mm-Silverman needle (n = 71). Four of the 107 patients (4%) who underwent percutaneous Menghini biopsy displayed hepatic hematoma on ultrasonography, and in 2 of these cases the hematoma was > 6 cm in diameter and persisted for more than seven months. In the group of patients who underwent laparoscopy-guided Silverman biopsy (n = 71) a liver hematoma occurred twice (3%). Both hematomas were small and disappeared within several days. There was no need for special therapeutic interventions due to complications. In contrast to recent data about Tru-cut and JAM-Shidi biopsy, the results of this study indicate that percutaneous Menghini biopsy and laparoscopy-guided Silverman biopsy are relatively safe diagnostic procedures.

[Prospective study of the incidence of ultrasound detectable liver hematomas after laparoscopically controlled liver puncture with the Silverman needle]

BACKGROUND

A high incidence of hepatic haematomas detected at sonography following percutaneous liver biopsy and laparoscopy-guided liver biopsy has recently been reported.

PATIENTS AND METHODS

Prompted by this report, we carried out a prospective study on 71 patients aged between 20 and 79 years (median age: 51 years). The patients were examined by ultrasound prior to and following laparoscopy-guided biopsy with the Silverman needle.

RESULTS

Only two of the 71 patients (3%) had a hepatic haematoma after biopsy. The haemangiomas had a maximum diameter of 2.6 cm, caused no pain, and disappeared again within ten days at the latest. No therapeutic measures were required.

CONCLUSION

The results of this study indicate that laparoscopy-guided liver biopsy with the Silverman needle is associated with relatively few complications.

Diagnosis of chronic pancreatitis by means of a sonographic secretin test

The pancreatic duct can be demonstrated today by sonography in about 90% of all persons examined. In 159 persons, aged 18-79 yr, we measured sonographically the pancreatic duct diameter before and after intravenous secretin injection. After secretin stimulation, 20 healthy controls and 90 patients without pancreatic disease showed a distinct pancreatic duct dilatation of 93 and 94% of basal duct diameter lasting only several minutes. No distinct secretin-induced duct enlargement was observed in 35 of 40 patients with chronic pancreatitis. Patients with chronic pancreatitis and circumscript duct stenosis even had a marked and longer-lasting duct dilatation of 156% of basal duct diameter after secretin stimulation. This study showed a high reliability of the sonographic secretin test in the diagnosis of chronic pancreatitis--even in an early stage--recording a sensitivity of 92.5%, a specificity of 93%, and a predictive value of 84%.

[Value of the brief neuropsychological tests for detection of acquired cognitive deficits. Exemplified by the Lehrl and Fischer c.I. (cerebral insufficiency) test]

The aim of the study was to find whether the c.I. test is useful for the exclusion and the demonstration of acquired cognitive deficits. In all, 195 patients with brain damage and 68 neurotic patients were examined with the c.I. test and with a comprehensive number of neuropsychological tests. The hit rate of the c.I.-test for the whole group was 67% and lay lower than the base rate of 74% brain damaged patients respectively only unessentially higher than the base rate of 64% patients with unambiguous acquired cognitive deficits. There were very low hit rates especially in patients with absent (46%) or low-grade cognitive deficit (54%) and with low (55%) or with high premorbid mental abilities (55%). Both the low correlations between the c.I. test and the validity criterion as well as the considerable overlapping of the c.I. test raw score distributions, grouped by grades of cognitive deficits, indicate serious deficiencies in the test. The extremely brief c.I. test possesses an inadequate grade of difficulty and cannot detect low- and medium-grade acquired cognitive deficits, and its orientation to ability-related global syndromes means that partial, multifactorial and general cognitive deficits are neglected. The c.I. test is therefore not useful as a screening method for the diagnosis of acquired cognitive deficits.

[Prognostic value of long-term pH-metry in the B-II resected stomach]

In a prospective study we investigated the clinical value of ambulatory 24-hour pH monitoring in the stomach after Billroth-II-resection. Recorded data of 10 patients with and 11 patients without ulcer recurrence after gastric resection were compared. The pH medians of the record periods "total time", "supine", "upright", "fasting" and "postprandial" were evaluated. Further the cumulative recording time of pH levels pH < 1, pH < 2, etc. was determined and compared in both groups. A pH median less than 2.8 "supine" indicated a postoperative ulcer recurrence with a sensitivity of 90% and specificity of 81%. A pH median less than 2.6 "fasting" predicted an ulcer relapse with a sensitivity of 90% and specificity of 72% (p < 0.001). In patients with ulcer recurrence pH was < 4 in more than 30% of total recording rime, pH < 5 in more than 45% and pH < 6 in more than 75% (sensitivity 90%, specificity 100%). According to these findings 24-hour pH monitoring seems to be useful for the prognostic assessment of the further course of ulcer disease after B II-surgery of the stomach. Thus pH monitoring results may be helpful in defining patient groups which may be candidates for acid reducing therapy to prevent ulcer recurrence.

A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct

Endoscopic insertion of biliary stents is the preferred method of palliation for inoperable malignant biliary obstruction; however, migration and clogging are frequent problems with conventional endoprostheses. We sought to determine if expandable metal stents offer improved palliation compared to conventional stents. Sixty-two patients with common bile duct lesions were randomized to receive polyethylene or metal stents. Stents were placed endoscopically or by the combined percutaneous-endoscopic route. Early results (< 1 month) were similar in both groups. Long-term follow-up (n = 28 polyethylene, median: 5 months; n = 27 metal, median: 5 months) showed a higher stent failure rate in the polyethylene (n = 12; 43%) compared to the metal group (n = 6; 22%). The incidence of cholangitis was significantly higher (p < 0.05) in the polyethylene (n = 10; 36%) compared to the metal group (n = 4; 15%). Life-table analysis showed a significantly reduced incidence of stent failure (p = 0.0035) in the metal stent compared to the polyethylene group. The total duration of hospital stay for treatment of stent related problems was significantly higher in the polyethylene (11.8 +/- 3 days) compared to the metal group (4 +/- 1.9 days; p = 0.02). The costs for retreatment because of stent failure were significantly higher in the plastic (DM 5900 +/- 1516) compared to the metal group (DM 2070 +/- 977). As a result, the overall costs (treatment of stent related complications & stents) were higher in the polyethylene group (DM 6000 +/- 1500).(ABSTRACT TRUNCATED AT 250 WORDS)

Self-expanding metal stents for palliation of malignant esophageal obstruction--a pilot study of eight patients

We sought to determine whether the application of a self-expanding metal stent enables palliation of malignant dysphagia with minimal risk. The results of pilot studies from two centers are reported. We treated 8 inoperable patients with a 14 mm self-expanding metal stent (Wallstent). The stent was applied without general anesthesia under mild i.v. sedation. The procedure was successful in all cases. No side effects were noted. In one patient, tumor ingrowth through the meshes of the stent occurred. This patient was additionally treated with a percutaneous gastrostomy. One patient experienced tumor overgrowth of the proximal end, necessitating laser treatment. Three patients were still alive after three months. The mean number of cumulative endoscopic interventions per patient was 2.2 (SD: +/- 2; median 2). The mean observation time was 10.7 weeks +/- 2 (median 12). Dysphagia was graded from 0 (normal swallowing) to 4 (inability to swallow saliva). Dysphagia was significantly (p less than 0.0005) reduced from grade 3.1 (SD: +/- 0.35) to 0.5 (SD: +/- 0.5) immediately after stenting. 62.5% of the patients were able to manage a virtually normal diet (in one of these patients dysphagia recurred six weeks after stent placement due to tumor ingrowth). Six patients (75%) were able to ingest all necessary calories orally. The application of a 14 mm self-expanding metal stent in cases of inoperable malignant esophageal obstruction seems to offer safe and effective palliation of malignant dysphagia.

Technical failure of biliary metal stent deployment in a series of 116 applications

Biliary metal stents are thought to offer improved long-term palliation of malignant biliary obstruction due to a lower incidence of migration and clogging. Placement of these stents is technically more complicated than that of plastic endoprostheses and requires two experienced physicians. We report the incidence and reasons for apparent malfunction of expandable metal stent deployment (Wallstents and Strecker stents). In 116 applications of 82 Wallstents (endoscopic approach: n = 33, transhepatic approach: n = 49), we observed 19 cases of stent malfunction due to technical problems of stent delivery. In 13 cases (15.8%), the restraining membrane of the Wallstent could not be retracted sufficiently to deliver the stent. There were 6 (17.6%) failures in 34 cases of Strecker stent deployment. In 3 cases, we noted difficult balloon removal, including avulsion of the balloon catheter shaft within the endoscope during attempted balloon removal in one case. In one case, the Strecker stent could only be released partially, requiring subsequent endoscopic extraction. In two patients, only partial expansion of one end of the Strecker stent could be achieved. Given the significant malfunction rate of expandable metal stents during stent delivery, further improvements in the delivery system of the metal stents are required.

[Metal or plastic endoprostheses in malignant obstructive jaundice. A randomized and prospective comparison]

In a prospective randomized trial 58 patients (24 men, 34 women, mean age 67 +/- 13 [42-89] years) with inoperable malignant jaundice were treated with synthetic (S; n = 29) or expanding metal endoprostheses (M; n = 29). After endoscopic retrograde cholangiopancreatography patients were divided into a group with hilar (K: n = 7; M: n = 6) or distal involvement (K: n = 22, M: n = 23). In two cases with hilar involvement (28%) a synthetic endoprosthesis could not be implanted, while early prosthesis occlusion (after 2 days) was observed in one case. But in this group it was possible to implant all metal stents. In the group with distal involvement both synthetic and metal endoprostheses were successfully implanted. In the M group the proportion of patients with prosthesis failure (13.6%) was significantly higher than in the S subgroup (40.9%). The cholangitis incidence was 9% in the M group, significantly less (P less than 0.05) than in the K group (40.9%). Duration of hospital stay to treat prosthesis-related complications was significantly less in the M group (average 2.9 days) than the K group (12.9 days). It would be a great advance in palliative tumour treatment if it were possible significantly to reduce, by means of metal stents, the incidence of late cholangitis and the duration of hospital stay necessary to treat late complications. But improvement in the technique of implanting metal stents would be essential before their general use in distal lesions can be recommended.

[Arterial embolization of an arteriovenous fistula with hemobilia after blind liver puncture]

Five days after percutaneous liver biopsy we observed in a 42-year-old man with alcoholic liver cirrhosis severe hemobilia requiring transfusions of packed red cells. By means of super-selective arterial embolization, using gelfoam, the bleeding source, an av-fistula, was successfully occluded. Iatrogenic hemobilia, although seen after percutaneous liver biopsy only in app. 0.005% of the cases, is today the most important cause of biliary bleeding, mainly as a complication (app. 3% of the cases) of the widespread use of interventional procedures of the biliary tree (e.g. PTCD). Therapeutically arterial embolization should be considered first if possible.

Effect of 5-diazouracil on the catabolism of circulating pyrimidines in rat liver and kidneys

The inhibitory effect of 5-diazouracil on the catabolism of circulating uracil and 5-fluorouracil was examined in the rat in vivo. Measurements of the activity of the entire enzymatic pathway of uracil catabolism in the cytosolic supernatant of different rat organs as well as the determination of the total amount of 5-fluorouracil catabolites, accumulated in these tissues, served to clarify their role in the complete systemic breakdown of uracil or 5-fluorouracil. The activity of the enzymatic pathway involved in uracil catabolism was estimated from the 14CO2 produced from [2-14C]uracil in the cytosolic supernatants. Complete degradation of uracil was detected only in the liver and, at a much lower rate, in the kidneys. Fifteen min after the i.p. injection of a tracer dose of 5-fluoro[6-14C]-uracil, more than 90% of the total radioactivity in blood plasma was associated with 5-fluorouracil catabolites. The relative amount of the major catabolite alpha-fluoro-beta-alanine and of dihydrofluorouracil in blood plasma was considerably suppressed after a pretreatment with 5-diazouracil inversely correlated with a 27-fold increase in the absolute amount of unchanged 5-fluorouracil. Control animals accumulated by far the highest amount of total acid-soluble radioactivity from 5-fluoro[6-14C]uracil in liver and kidneys. Total radioactivity in all other organs was much lower and was comparable to the amount of label in blood plasma. In liver and kidneys, the sum of total acid-soluble catabolites including dihydrofluorouracil, alpha-fluoro-beta-ureidopropionic acid, and alpha-fluoro-beta-alanine made up more than 98% of the label correlating with minimal salvage utilization of the base analogue in both organs. Injection of 5-diazouracil 2 h before a tracer dose of 5-fluoro[6-14C]uracil strongly inhibited the accumulation of labeled catabolites in liver and kidneys causing a fall in total acid-soluble radioactivity in both tissues by 75 and 66%, respectively. In blood plasma and all other organs, however, pretreatment with 5-diazouracil was followed by a 2-fold enhancement of the radioactivity contents, mostly due to the appearance of unchanged 5-fluorouracil. Under these conditions, there was a 2.6- to 4-fold increase in the relative proportion of cis-diol group-containing anabolites of 5-fluorouracil in liver and in kidneys. Within 2 h, 12.7% of the administered radioactivity from 5-fluorouracil was excreted into bile. 5-Diazouracil lowered the biliary excretion of radioactivity to 2% of the injected dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Non-surgical biliary drainage: endoscopic conversion of percutaneous transhepatic into endoprosthetic drainage

Percutaneous transhepatic drainage (PTD) is associated with many long-term complications. Therefore a large-diameter endoscopic endoprosthesis is preferentially employed to bridge a malignant obstruction of the biliary tract. Only if the placement of an endoprosthesis fails, must PTD be established. We present a simple method for converting PTD into a large endoprosthesis (14 F) with the aid of endoscopy. We have performed this conversion successfully in 8 patients without complications.

[X-ray and endoscopic diagnosis of ulcerative colitis and Crohn disease]

The indication for radiologic or endoscopic examinations in ulcerative colitis and Crohn's disease depends on the stage of the disease. Advantages of the colonoscopy are the possibility to take biopsies, the coloured few of lesions and the avoidance of X-rays in the management of young patients. Radiology is superior to endoscopy in estimating shortening of the bowel, stenoses and fistulas.

Hepatic carbamoyl phosphate metabolism. Role of cytosolic and mitochondrial carbamoyl phosphate in de novo pyrimidine synthesis

The interrelationship between the two carbamoyl phosphate pools in intact hepatocytes and intact liver was studied with respect to de novo pyrimidine synthesis by use of selective inhibitors of the mitochondrial and the cytosolic carbamoyl-phosphate synthetase. Inhibition of mitochondrial carbamoyl phosphate synthesis by 4-pentenoate was without effect on galactosamine-stimulated pyrimidine synthesis. Conditions favouring mitochondrial carbamoyl phosphate accumulation, like excess ammonium ions or L-norvaline, led to an increase in pyrimidine synthesis bypassing the feedback inhibition of cytosolic carbamoyl-phosphate synthetase by UTP. A stimulation of pyrimidine synthesis was not observed when the carbamoyl phosphate accumulation was due to aspartate deficiency in the presence of aminooxyacetate. The full response of pyrimidine synthesis to excess ammonium ions was restored, even in the presence of aminooxyacetate, when aspartate was substituted. This is explained by an inhibition of aspartate carbamoyltransferase flux [in view of the Km (aspartate = 0.7 mmol/l) of this enzyme] resulting from a 90% decrease in aspartate tissue levels. Acivicin, the inhibitor of cytosolic carbamoyl-phosphate synthetase, completely abolished the galactosamine-induced stimulation of pyrimidine synthesis, but was without effect on the stimulation of pyrimidine synthesis by ammonium ions and L-norvaline. It is concluded that experimental changes in mitochondrial carbamoyl phosphate content exert effects on de novo pyrimidine synthesis; however, it is considered unlikely that relevant amounts of mitochondrial carbamoyl phosphate are used for pyrimidine synthesis under physiological conditions. In addition the data point to a potential regulatory role of aspartate in hepatic pyrimidine synthesis.

Uridine catabolism in Kupffer cells, endothelial cells, and hepatocytes

Kupffer cells, endothelial cells, and hepatocytes were separated by centrifugal elutriation. The rate of uracil formation from [2-14C]uridine, the first step in uridine catabolism, was monitored in suspensions of the three different liver cell types. Kupffer cells demonstrated the highest rate of uridine phosphorolysis. 15 min after the addition of the nucleoside the label in uracil amounted to 51%, 13%, and 19% of total radioactivity in the medium of Kupffer cells, endothelial cells, and hepatocytes, respectively. If corrected for Kupffer cell contamination, hepatocyte suspensions demonstrated similar activities as endothelial cells. In contrast to non-parenchymal cells, hepatocytes continuously cleared uracil from the incubation medium. The lack of uracil consumption by Kupffer cells and endothelial cells points to uracil as the end-product of uridine catabolism in these cells. Kupffer cells and endothelial cells did not produce radioactive CO2 upon incubation in the presence of [2-14C]uridine. Hepatocytes, however, were able to degrade uridine into CO2, beta-alanine, and ammonia as demonstrated by active formation of volatile radioactivity from the labeled nucleoside. There was almost no detectable formation of thymine from thymidine or of cytosine, uracil, or uridine from cytidine by any of the different cell types tested. These results are in line with low thymidine phosphorolysis and cytidine deamination in rat liver. Our studies suggest a co-operation of Kupffer cells, endothelial cells, and hepatocytes in the breakdown of uridine from portal vein blood with uridine phosphorolysis predominantly occurring in Kupffer cells and with uracil catabolism restricted to parenchymal liver cells.

De novo pyrimidine biosynthesis in isolated rat hepatocytes. Quantitative aspects of the regulation by UTP

Quantitative aspects of de novo pyrimidine biosynthesis in rat hepatocytes were monitored. A reduction of intracellular UTP contents by different concentrations of D-galactosamine led to a dose-dependent increase of 14CO2 incorporation into the sum of all acid-soluble uracil nucleotides. In controls the rate of de novo synthesis which was calculated from the incorporation rate of 14CO2 into the sum of all acid-soluble uracil nucleotides was 0.014 mumol X h-1 X g-1 compared to 0.056 mumol X h-1 X g-1 wet weight of liver in situations of a maximally stimulated de novo synthesis. Incubation of hepatocytes with uridine led to a dose-dependent reduction of 14CO2 incorporation to less than 25% of the amount incorporated in the controls. Alterations of the CTP content had no influence on the 14CO2 incorporation. In the presence of high D-galactosamine concentrations the increase of the total amount of acid-soluble uracil nucleotides exceeded the rate of the de novo synthesis derived from the incorporation of 14CO2 into the sum of the acid-soluble uracil nucleotide pool. It was also greater than the increase of the total amount of intra- and extracellular orotate after acidic hydrolysis--even in the presence of 6-azauridine, which stimulated de novo pyrimidine biosynthesis by itself.

First clinical experiences with a selective chemotherapy of hepatocellular carcinoma with 5-fluorouridine in combination with other antipyrimidines

Sixteen unselected patients with non-resectable hepatocellular carcinoma were treated in a phase I study with 261 cycles of D-galactosamine and 6-azauridine prior to 5-fluorouridine. Thirty % of the patients survived for more than one year without signs of tumor progression and with an unchanged performance status. The compatibility of this chemotherapeutical method was quite satisfactory. The only extrahepatic side effect was a leucopenia and/or thrombocytopenia which was reversible upon reduction of the 5-fluorouridine dose. The heterogeneity of the 16 patients treated to date does not allow a definite statistical evaluation of the reported clinical observations and results. A final decision about the clinical applicability of this concept of a selective chemotherapy of hepatocellular carcinoma requires further experience.

The glutamine analog acivicin as antipyrimidine. Studies on the interrelationship between pyrimidine and urea synthesis in liver

The inhibition of cytosolic carbamoyl-phosphate synthetase II by acivicin was used to study the role of the cytosolic carbamoyl phosphate pool as the exclusive substrate source for de novo pyrimidine synthesis in rat hepatocytes. De novo pyrimidine synthesis was stimulated: 1. by uridine triphosphate deficiency (incubation with D-galactosamine) leading to a stimulation of cytosolic carbamoyl phosphate synthesis, and 2. by accumulation and efflux of mitochondrial carbamoyl phosphate (incubation with ammonium ions and L-norvaline). The stimulated orotate formation from cytosolic carbamoyl phosphate in UTP depleted cells was completely blocked by acivicin. It was not influenced by an inhibition of mitochondrial carbamoyl phosphate synthesis mediated by 4-pentenoate, since mitochondrial carbamoyl phosphate did not participate in cytosolic pyrimidine synthesis even in the presence of ammonium ion concentrations maintaining physiological rates of urea synthesis. An excess of ammonium ions led to an artificial accumulation and efflux of mitochondrial carbamoyl phosphate, which could be avoided by 4-pentenoate. The non-regulated stimulation of pyrimidine synthesis from surplus mitochondrial carbamoyl phosphate was not inhibited by acivicin. Utilization of mitochondrial carbamoyl phosphate for de novo pyrimidine synthesis presumably does not occur under physiological conditions because mitochondrial CP efflux depends on the accumulation of this metabolite in the mitochondria under experimental or pathological circumstances. Acivicin inhibition of CPS II thus cannot be bypassed by mitochondrial CP. It is suitable as inhibitor of the physiological de novo pyrimidine synthesis.

[Systemic disease closely related to Cogan's syndrome (author's transl)]

In a 51-year-old patient with non-syphilitic interstitial keratitis and disturbances of inner ear function (Cogan's syndrome) the course of the disease could be followed for 8 years. Organ manifestations which indicated generalised vascular disease were present in accordance with reports in the literature of this rare syndrome. In addition to multiple digital arterial occlusions, recurrent pulmonary infiltrations were observed which have not previously been described in connection with this syndrome. With the exception of the inner ear hearing loss the symptoms could be improved by systemic administration of corticosteroids and azathioprine. The patient remained free of recurrence for over three years.

[Approaches to a selective chemotherapy of hepatocellular carcinoma (author's transl)]

1. An improvement of the chemotherapy of hepatocellular carcinoma with adriamycin or 5-fluorouracil and a reduction of side effects has been achieved by intra-arterial administration of the drugs. This treatment provides a somewhat extended survival but no cure. 2. The treatment of hepatocellular carcinoma in patients by reduction of an inactive precursor of a cytocidal alkylating agent by azoreductase of the tumor showed no therapeutic effect. 3. A selective hepatocellular uptake of drugs coupled to asialoglycoproteins has been described. An application of this concept for the chemotherapy of hepatocellular carcinoma seems doubtful since a loss of binding proteins for desialylated glycoproteins during experimental hepatocarcinogenesis has been demonstrated. 4. The increased uptake of 5-fluorouridine in hepatomas after induction of a tissue-specific depletion of uridine 5'-triphosphate and cytidine 5'-triphosphate provides an effective experimental chemotherapy with limited side effects. A clinical use of this new concept for the chemotherapy of hepatocellular carcinoma may serve as a useful approach.

[Biochemical and pathophysiological aspects of hyperammonaemia (author's transl)]

1. Ammonia liberated continuously in large amounts in muscle, kidney and brain is used immediately for the synthesis of mainly glutamine because of the toxic effects of elevated ammonia concentrations. After glutamine hydrolysis in the liver ammonia serves as substrate for the urea biosynthesis. In ureotelic animals urea is the quantitatively most important product for the elimination of surplus nitrogen. 2. The rate of urea biosynthesis depends on the amount of surplus nitrogen and acts as regulatory factor for the nitrogen balance of the adult organism. 3. Urea cycle abnormalities in liver diseases or inborn enzymatic defects are important factors leading to hyperammonaemia in patients. 4. The hyperammonaemia induces an increase of the rate of hepatic pyrimidine nucleotide biosynthesis as a consequence of an ineffective feedback inhibition of the glutamine-dependent carbamoyl phosphate synthetase. 5. The distribution of ammonia between intra- and extracellular space and the amount of ammonium ions excreted in the urine depend on the pH value. An alkalosis induces an intracellular ammonia load and inhibits the urinary ammonium ion excretion, which is increased in acidosis as one mechanism of protein elimination. 6. The ammonia-induced inhibition of the citric acid cycle by an alpha-ketoglutarate deficiency is one important reason for the neurotoxicity of ammonia, which is the main point in the pathogenesis of hepatic coma.

Control of pyrimidine biosynthesis in the perfused liver. Feedback inhibition of glutamine-dependent carbamoyl phosphate synthetase

The site of feedback inhibition of the biosynthesis of pyrimidine nucleotides de novo was investigated in the isolated perfused rat liver. Hepatic uridine phosphate contents were specifically depleted by use of D-galactosamine. The effective activities of enzymes involved in the synthetic pathway were deduced from the rats of incorporation of labeled precursors into the acid-soluble uracil nucleotide pool and into some intermediates of the pathway. The labeling of hepatic urea was also monitored. When the uridine phosphate contents were less than 20% of controls, the incorporation of [14-C]-bicarbonate was stimulated about 20-fold. Label from [U-14C]oxaloacetate used as permeable precursor of intrace-lular aspartate was introduced into the uridylates to the same extent in normal and UTP-depleted livers. Similar results were obtained with labeled carbamoyl phosphate although the uptake of this compound by the liver was rather low. The lack of labeling of urea from exogenous carbamoyl phosphate does not indicate a free exchange of extra- and intramitochondrial carbamoyl phosphate. [ureido-14C]Ureidosuccinate produced in normal and D-galactosamine-treated livers almost identical labeling patterns of dihydroorotate, orotate and orotidine 5'-phosphate. The steady state concentrations of these intermediates were all below 15 nmol/g liver wet weight.