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Biomedical subjects

H Peters

Publications and source records attributed to H Peters.

At least 91 records · Page 5Linked to original sources

Spontaneous regression of hepatocellular carcinoma.

A 72-year-old Caucasian woman suffered from histologically-proven advanced hepatic cancer, for which she received no treatment. She had been a regular drinker for a long time. Serologic markers for hepatitis B and C were negative. In spite of her poor prognosis, she remained in good clinical condition and at 14 months of follow up the hepatocellular carcinoma could not be visualised any more radiologically. At that time the serum alpha foetoprotein concentration was normal. At present, 28 months after diagnosis, the patient is doing well and her tumour still appears to be in complete spontaneous remission.

Aged↗

Angiotensin II and L-arginine in tissue fibrosis: more than blood pressure.

Angiotensin II (Ang II) blockade and restriction of dietary protein are thought to retard progression of renal disease primarily by reducing glomerular capillary pressure and thereby reducing injury to renal tissues. Relatively recent data suggest that both of these therapies may also act through pressure-independent mechanisms to reduce repair processes that follow tissue injury and which, if not self-limited, can continue to cause tissue fibrosis and organ failure. We review recent data suggesting that Ang II is a profibrotic molecule independent of blood pressure. Therapeutic actions of dietary restriction of total protein and restriction of the amino acid L-arginine that appear independent of pressure are also discussed. These effects are separated into those that reduce injury and those that reduce tissue repair. Finally, we ask whether the Ang II blockade or restriction of dietary protein could be more effective if they were aimed not only at limiting injury, but also at halting excessive repair.

Angiotensin II↗

Treatment of Graves' hyperthyroidism with radioiodine: results of a prospective randomized study.

In this paper, we report the results of a randomized prospective study on radioiodine treatment in patients with Graves' hyperthyroidism. Complete data were obtained in group 1 from 98 patients 6 months after application of a standard activity of 15 mCi (555 MBq) of 131I and in group 2 from 107 patients who received a target dose of 100 Gy. In group 1, the overall success rate was 71%, but the results in the subgroups clearly were related inversely to the thyroid volume, ranging from 100% in patients with a thyroid volume < 15 mL to about 20% in those with a thyroid size of > 60 mL. In contrast, patients who received a target of 100 Gy showed very similar results, with success rates of about 40-50% in all but one subgroup. Only patients with a thyroid volume < 15 mL had a success rate of about 80%. But due to an incidental increase of uptake and/or effective half-time from the test to the therapy activity, this subgroup received a target dose of about 160 Gy. Additional calculation of the actual target dose in group 1 (standard activity) showed that, with a dose of 200 Gy, a success rate of 80% was obtained. Also, the thyroid volume reduction was related inversely to the target dose. Because the literature is abundant, only a restricted number of references are discussed that are either in agreement with our results or in sharp contrast to them. The reason for these discrepant results might be the difference in the scheme of pretreatment or the different alimentary iodine supply between, for example, Great Britain and the United States on the one hand and Germany on the the other hand.

Adult↗

Transforming growth factor-beta in human glomerular injury.

Overexpression of the cytokine transforming growth factor-beta has been identified as the key mediator of chronic progressive kidney fibrosis in experimental and human kidney diseases. The renoprotective effects of angiotensin II blockade and low-protein diets have recently been linked to downregulation of transforming growth factor-beta production. Neutralizing the actions of transforming growth factor-beta by decorin gene therapy appears to be a highly effective new approach in the treatment of renal fibrosis.

Angiotensin II↗

[The prevention of the recurrence of endemic goiter. The efficacy of a once-a-week dose of 1.53 mg iodide].

OBJECTIVE: To investigate the efficacy of 1.53 mg iodide administered once weekly in the prophylaxis of goitre recurrence in patients with endemic euthyroid goitre after initial treatment to reduce the goitre size. PATIENTS AND METHODS: 46 consecutive patients who had undergone initial L-thyroxine, iodide or combined treatment were included in the prospective study. Thyroid volume was measured sonographically at the beginning as well as 6 and 18 months later. An increase in thyroid volume of more than 15% was taken as recurrence. RESULTS: The study was concluded in 41 patients. During the prophylaxis mean thyroid volume increased from initially 21.7 +/- 9.9 ml to 22 +/- 10.9 ml after 6 months and to 24.5 +/- 12.1 ml after 18 months (P < 0.01). While thyroid volume remained unchanged in at least two thirds of patients, a recurrence occurred in 32% (n = 13; from initially 22.7 +/- 9.7 ml, to 26.3 +/- 11.3 ml at 6 months and to 29.7 +/- 12.3 ml at 18 months). In all patients with a recurrence a doubling of the iodide dosage to twice weekly 1.53 mg for 6 months reduced thyroid volume again (mean of 25.7 +/- 10.0 ml; P < 0.01). CONCLUSIONS: In at least two third of patients a once-weekly dose of 1.53 mg iodide is a reliable means of preventing a recurrence of endemic euthyroid goitre, but in the remainder the same dose must be increased to twice weekly.

Adolescent↗

A randomized, prospective trial of stapled lung reduction versus laser bullectomy for diffuse emphysema.

Two procedures (laser bullectomy and lung reduction surgery with staples) are currently available for the surgical treatment of patients with diffuse emphysema. We compared the efficacy of these two surgical approaches in 72 patients, aged 67 +/- 7 years (mean +/- standard deviation), who had diffuse emphysema scored as severe on computed tomography and severe fixed expiratory airflow obstruction. The patients were prospectively randomized to undergo either neodymium:yttrium aluminum garnet contact laser surgery (n = 33) or stapled lung reduction surgery (n = 39) by unilateral thoracoscopy. The operative mortalities were 0% and 2.5%, respectively. No significant differences were noted between the groups (p < 0.05) with respect to operating time, hospital days, or air leakage for more than 7 days. However, a delayed pneumothorax developed in six patients (18%) who had laser treatment (p = 0.005). The operations eliminated dependency on supplemental oxygen in 52% of the laser group and 87.5% of the stapled lung reduction group (p = 0.02). The mean postoperative improvement in the forced expiratory volume in 1 second at 6 months was significantly greater for the patients undergoing the staple technique (32.9% vs 13.4%, p = 0.01) than for the laser treatment group.

Aged↗

Reduction in thyroid volume after radioiodine therapy of Graves' hyperthyroidism: results of a prospective, randomized, multicentre study.

The reduction in thyroid size in 92 patients treated with radioiodine for Graves' thyrotoxicosis was monitored by ultrasound volumetry. The patients were randomly treated with either a standard 131I activity of 555 MBq or an activity calculated to deliver a thyroid dose of 100 Gy. Within 1 year after radioiodine treatment, a remarkable volume reduction of about 71% (median) (quantile 25% (Q 25) = 49%, Q 75 = 82%, n = 67) was observed. The bulk of this reduction (median 57%, Q 25 = 21%, Q 75 = 74%, n = 92) was found within the first 6 months. Statistical analysis reveals that the effect was clearly related to the thyroid dose actually achieved during therapy. The median reduction obtained 6 months after radioiodine application was 45% for < 100 Gy, 56% for 100-200 Gy and 67% for > 200 Gy (n = 28, 39, 25 respectively). Twelve months after radioiodine application, the effect became less evident: 53%, 68% and 75% respectively (n = 17, 29, 21). The higher median thyroid dose actually achieved by standard than by calculated activity (215 Gy vs. 116 Gy) explains the more pronounced volume reduction in the standard group than in the calculated group; 60% vs. 47% 6 months (n = 47, 45) after radioiodine treatments and 74% vs. 66% 12 months (n = 31,36) after radioiodine application. The relative reduction in thyroid size was just as marked in patients with large thyroids as in those with small glands. The goitre prevalence (thyroid volume > 20 mL in women and > 25 mL in men) was reduced from 73% to only 16% 1 year after radioiodine treatment. In patients with a thyroid volume of more than 60 mL, the median pretherapeutic thyroid volume of 102 mL was reduced to 29 mL. In conclusion, radioiodine treatment in Graves' hyperthyroidism sufficiently reduces thyroid volume in a dose-dependent manner. The findings of this study demonstrate that radioiodine is also an attractive mode of therapy for Graves' patients with substantial thyroid enlargement.

Adult↗

Prolonged enteroviral infection in a patient who developed pericarditis and heart failure after bone marrow transplantation.

We described a patient who developed heart failure and pericarditis after bone marrow transplantation for a hematologic malignancy. The patient died of heart failure complicated by pneumonia. Despite extensive surveillance, an infectious cause for the heart failure was not found while he was alive. In addition, cultures of specimens obtained at autopsy did not reveal a cause for the heart failure. Enterovirus was detected by the polymerase chain reaction (PCR) in two samples of pleural fluid that were obtained 21 days apart while he was alive. After the patient died, enteroviral RNA was also detected in his lungs, liver, and spleen, indicating a generalized infection. Analysis of the PCR products revealed sequences sharing close homology with the coxsackie B-like group of enteroviruses. In addition to reporting this case, we review the literature regarding enteroviral infections after transplantation.

Adult↗

Staging urinary bladder cancer after transurethral biopsy: value of fast dynamic contrast-enhanced MR imaging.

PURPOSE: To evaluate contrast enhancement patterns of urinary bladder cancer and surrounding structures and to evaluate a fast dynamic first-pass magnetic resonance (MR) imaging technique in tumor and node staging and in differentiation of urinary bladder cancer from postbiopsy effects. MATERIALS AND METHODS: Sixty-one consecutive patients with histologically proved urinary bladder cancer were referred to undergo unenhanced and dynamic MR imaging 1-4 weeks after transurethral resection or biopsy. Subtraction and time (to beginning of enhancement) images were acquired. RESULTS: Results with unenhanced T1- and T2-weighted images were compared with those obtained with the unenhanced images plus dynamic contrast material-enhanced single-section turbo fast low-angle shot (FLASH) images. Urinary bladder cancer started to enhance 6.5 seconds +/- 3.5 (standard deviation) after the beginning of arterial enhancement, which was 4 seconds earlier than most other structures (postbiopsy tissue, 13.6 seconds +/- 4.2). In differentiation of postbiopsy tissue from malignancy on the basis of the beginning of enhancement depicted on time and subtracted images, accuracy improved from 79% to 90% (P < .02) and specificity improved from 33% to 92% (not significant). Overall, tumor staging accuracy improved significantly from 67% to 84% (P < .01) by adding the turbo FLASH images. CONCLUSION: Fast dynamic first-pass MR imaging, with at least one image acquired every 2 seconds, improved delineation of urinary bladder cancer, tumor staging, and detection of metastases.

Biopsy↗

Dietary L-arginine in renal disease.

The amino acid L-arginine is a substrate for at least three products involved extensively in tissue injury and fibrosis. L-arginine is metabolized to L-proline, a major constituent of the collagen that makes up fibrotic extracellular matrix. L-arginine is a precursor for polyamines, which are required for proliferative responses characteristic of many renal disease. L-arginine is also the sole substrate for generation of nitric oxide (NO) which, produced in large quantities by macrophages, has been implicated in tissue injury. On the other hand, NO produced in small quantities by endothelium is a critical vasodilator. Given the importance of elevated intraglomerular pressure in renal injury, it is perhaps not surprising that dietary L-arginine supplementation increase NO generation and is beneficial in reducing intraglomerular pressure and subsequent disease. Other data, based on the therapeutic effects of low protein diets, have suggested that L-arginine restriction limits NO-mediated glomerular injury and greatly reduces matrix accumulation, consistent with the idea that limitation of substrate effectively diminishes injurious NO levels, polyamine synthesis, and collagen production.

Animals↗

Tandem mass spectrometry and nuclear magnetic resonance spectroscopy studies of Candida bombicola sophorolipids and product formed on hydrolysis by cutinase.

Natural mixtures of sophorolipids produced by the yeast Candida bombicola have been analyzed by fast atom bombardment (FAB)-MS and collision-induced dissociation (CID)-MS. Some pure components have been analysed by two-dimensional NMR spectroscopy. The presence of acidic, lactonic, and O-acetylated forms and the position of double bonds in the fatty acid part of these glycolipids can be easily inferred from positive and negative ion FAB-mass spectra. Details about position of O-acetylation can be obtained from CID mass spectra of [M+H]+ and [M-H]- ions and from the NMR spectra. Differences in CID fragmentation between protonated and sodiated molecular ions are discussed in detail. Enzymatic hydrolysis of 6',6"-di-O-acetyl sophorolipid lactone by cutinase from Fusarium solani results specifically in the removal of the 6'-O-acetyl group, whereas the 6"-O-acetyl and lactone group are resistant. This specificity is explained from a three-dimensional model of the sophorolipid generated on the basis of the short 1H,1H distances as inferred from the NMR (ROESY) spectra.

Anions↗

Differential expression of the chicken Pax-1 and Pax-9 gene: in situ hybridization and immunohistochemical analysis.

We report the cloning, partial sequence analysis, and spatiotemporal expression of the chicken Pax-1 (chPax-1) and Pax-9 (chPax-9) gene, two closely related members of the paired box-containing (PAX) gene family. The chPax-1 gene encodes RNAs of 2.0 and 4.3 kb and a 42 kD protein while the gene products of chPax-9 are represented by 1.9 and 3.1 kb transcripts and a 39 kD protein. In situ hybridization and immunohistochemical analyses reveal chPax-1 expression in the developing pectoral girdle, in cells of the ventral part of sclerotomes, in sclerotome cells of the perichordal tube, and, later in development, in sclerotome-derived cells of the intervertebral disks. Other chPax-1 expression domains detected in the mesenchyme surrounding the atlas and axis and in chondrocytes of immature vertebral bodies, so far unreported for mouse Pax-1, correlate with as yet unexplained malformations in the mouse Pax-1 mutant undulated and Undulated-short tail. Overlapping expression of chPax-1 and chPax-9 is detected in epithelial cells of the embryonic and adult thymus and in cells of the developing intervertebral disks. Unlike chPax-1, however, chPax-9 is not expressed in those perichordal sclerotome cells which are thought to give rise to vertebral bodies. Furthermore, chPax-9 gene products are detected in circumscribed areas of mesenchyme in the metatarsus and in entodermal derivatives, i.e., in the lining epithelium of the developing pharynx and of the embryonic and adult esophagus.

Amino Acid Sequence↗

Two recurrent nonsense mutations and a 4 bp deletion in a quasi-symmetric element in exon 37 of the NF1 gene.

We screened a total of 92 unrelated patients with neurofibromatosis type 1 (NF1) for mutations in exon 37 of the NF1 gene, by using temperature gradient gel electrophoresis. Two novel mutations were found: a 4 bp deletion in a so-called quasi-symmetric element (6789del-TTAC) and a recurrent nonsense mutation, which was identified in two unrelated patients, at codon 2264 (C6792A). The independent origin of the latter mutation in two families was confirmed by haplotype analysis. The nonsense mutation and the 4 bp deletion are both predicted to lead to a truncated protein product lacking the C-terminal 20% (approximately) of its sequence. The occurrence of three independent mutations among 92 NF1 patients at codons 2263-2264 (exon 37) suggests that a specific search for mutations in this area should be undertaken in screening programs for NF1 mutations.

Base Sequence↗

Radioiodine therapy of Graves' hyperthyroidism: standard vs. calculated 131iodine activity. Results from a prospective, randomized, multicentre study.

The present prospective, randomized, multicentre study was performed to directly compare for the first time the effectiveness of a standard activity of 555 MBq 131iodine vs. an activity calculated to deliver 100 Gy for treatment of Graves' thyrotoxicosis. Therapeutic success was defined as the elimination of hyperthyroidism 6 months after radioiodine application (range 4.5-8 months). A success rate of more than 90% in eliminating hyperthyroidism was reported for both approaches, but only in retrospective investigations. Investigated prospectively, hyperthyroidism was eliminated in only 71% of the patients receiving standard activity (70/98) and 58% of those randomized for calculated activity (62/107). In the patients with standard activity, therapeutic success was inversely related to thyroid size. The rate was 100% for thyroid volumes < or = 15 mL, 95% for 16-30 mL, 68% for 31-45 mL, 44% for 46-50 mL, 20% for 61-75 mL and 25% for > or = 75 mL. In those patients with an activity calculated to deliver 100 Gy (except in those with a volume < or = 15 mL) this size/outcome dependency was almost compensated. The rates were 86%, 65%, 45%, 61%, 41% and 45%, respectively. Furthermore, detailed statistical analysis revealed a strong correlation between the success of therapy and the radiation dose actually absorbed by the thyroid. The rate was 11% for a target dose of 50 Gy, 50% for 100 Gy, 67% for 150 Gy, 80% for 200 Gy, 84% for 250 Gy, 88% for 300 Gy, 90% for 350 Gy and 93% for 400 Gy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Lactate transport in cultured glial cells.

Uptake of L-lactate was investigated with a radioactive tracer method in cultured rat glioma cells and in astroglia-rich primary cultures derived from rat brain. In the glioma cells, a saturable component of uptake was identified with half-maximal uptake occurring at 1.0 +/- 0.4 mM lactate. In addition, a non-saturable component dominated the uptake at high concentrations of lactate. In astroglia-rich primary cultures, no saturable component of uptake could be detected in the concentration range studied (0.1-15 mM). In conclusion, lactate uptake at physiological concentrations is predominantly mediated in the glioma cells by a carrier-dependent process, whereas in astroglial cells, simple diffusion appears to be the dominant way of lactate transport.

Animals↗

Staging urinary bladder cancer: value of T1-weighted three-dimensional magnetization prepared-rapid gradient-echo and two-dimensional spin-echo sequences.

OBJECTIVE: The purpose of this study was to evaluate a magnetization prepared-rapid gradient-echo (MP-RAGE) sequence as a three-dimensional T1-weighted MR imaging technique for staging urinary bladder cancer and to compare this technique with a commonly used two-dimensional T1-weighted spin-echo sequence technique. SUBJECTS AND METHODS: For 28 consecutive patients with urinary bladder cancer, MR findings and staging results were compared with histopathologic findings after surgery or autopsy. MR imaging was performed at 1.5 T with a Helmholtz double-surface coil. Conventional T1-weighted spin-echo, three-dimensional MP-RAGE, T2-weighted spin-echo or turbo-spin-echo, and dynamic T1-weighted fast gradient-echo sequences were used. Signal difference-to-noise ratios and T1 contrast were calculated by use of operator-defined regions of interest. RESULTS: The signal difference-to-noise ratios for fluid-tumor and fat-tumor were, respectively, factors of 1.6 and 2.7 better with T1-weighted spin-echo sequences. T1 contrast of fluid-tumor was a factor of 2.6 better with three-dimensional MP-RAGE sequences, resulting in better recognition of small tumors, ascites, and dilated ureters. T1 contrast for fat-tumor was a factor of 2.0 better with T1-weighted spin-echo sequences. With the MP-RAGE sequence, motion artifacts were fewer in number than those noted with the T1-weighted spin-echo sequence, and susceptibility artifacts were equal in number to those noted with the T1-weighted spin-echo sequence. Using the three-dimensional technique, we performed off-line reconstruction of 1- to 2-mm high-resolution images in every desired plane. Because of higher spatial resolution, the availability of multiplanar reconstructions, and better fluid-tumor contrast and despite lower signal difference-to-noise ratios, three-dimensional MP-RAGE images resulted in better recognition of local tumor extension (n = 11), adhesions and bowel wall invasion (n = 5), lymph node metastases (n = 2), and bone marrow metastases (n = 2). The staging accuracy for the combination of three-dimensional MP-RAGE, T2-weighted, and dynamic sequences was 93%; that for the combination of two-dimensional T1-weighted spin-echo, T2-weighted, and dynamic sequences was 78%. Nodal staging was also more accurate with MP-RAGE sequences (accuracy of 93% vs 86% for T1-weighted spin-echo sequences). CONCLUSION: Compared with two-dimensional T1-weighted spin-echo imaging, three-dimensional MP-RAGE imaging resulted in a 15% improvement in staging. Our findings suggest that optimal staging of urinary bladder carcinoma requires three-dimensional imaging techniques.

Adult↗