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Biomedical subjects

A Zimmermann

Publications and source records attributed to A Zimmermann.

At least 199 records · Page 11Linked to original sources
PubMed1994

Recovery of airway structure and function after hyperoxic exposure in immature rats.

We have previously demonstrated that hyperoxic exposure (> 95% O2 for 8 d) induces airway cholinergic hyperresponsiveness and remodeling in 21-d-old rats. To examine the potential relationship between airway hyperresponsiveness and remodeling in these animals, we exposed rats to air or hyperoxia for 8 d, returned them to air-breathing, and measured airway responsiveness to inhaled acetylcholine (ACh) and layer thicknesses immediately after or 16 or 48 d after cessation of air or O2 exposure. The ACh concentration required to increase resistance by 100% (EC200ACh) was calculated by linear interpolation. Small airway (circumference < 1,000 microns) and medium-sized, conducting airway (1,000 to 3,000 microns) epithelial and smooth muscle layer mean thicknesses and fractional areas (layer area/luminal cross-sectional area) were determined from lung sections by contour tracing using a digitizing pad and computer. As we reported previously, after 8 d of O2 exposure, group mean log EC200ACh was significantly reduced relative to that in control animals (p < 0.001). Similarly, hyperoxic exposure was associated with significant increases in all parameters of airway layer thickness assessed (p < 0.05). However, by 16 d after cessation of O2 exposure, there were no longer statistically significant differences in log EC200ACh, airway layer thickness, or fractional area between control and O2-exposed animals. Further studies, in a second cohort of animals killed 0, 3, 6, 8, or 13 d after cessation of O2 exposure, demonstrated progressive reductions in small airway epithelial and smooth muscle layer thicknesses, confirming that hyperoxia-induced airway remodeling resolves by approximately 2 wk after termination of O2 exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

Hyperoxia increases airway cell S-phase traversal in immature rats in vivo.

Exposure of 21-day-old Sprague-Dawley rats to hyperoxia (> 95% O2 for 8 days) causes thickening of the airway epithelial and smooth muscle layers. To test the hypothesis that hyperoxic exposure increases airway layer DNA synthesis, we labeled the nuclei of cells undergoing S-phase by administering the thymidine analog bromodeoxyuridine (BrdU). BrdU was administered on days 3 and 4, 5 and 6, or 7 and 8 of air or O2 exposure, and the lungs were harvested immediately thereafter. Histologic sections were stained with an avidin-biotin-immunoperoxidase stain that revealed BrdU incorporation into nuclei, and a hematoxylin counterstain. After 4 days of air or O2 exposure, there was no difference in BrdU fractional labeling between control and hyperoxic animals. Thereafter, fractional BrdU labeling of the small airway (circumference < 1,000 microns) epithelium and smooth muscle layer was significantly increased in O2-exposed animals (P < 0.01, unpaired t test). The fractional labeling of larger, central airway smooth muscle layer cells was also increased after 8 days of O2 exposure (P < 0.01). In another cohort of O2-exposed animals, measurements of airway layer dimensions demonstrated increases in small airway epithelial and smooth muscle layer thickness that paralleled the time course seen for BrdU incorporation. We conclude that O2 exposure of immature rats increases airway epithelial and smooth muscle layer cellular DNA synthesis. These data suggest that hyperplasia of airway epithelial and smooth muscle layer cells may contribute to hyperoxia-induced airway remodeling.

Animals↗
PubMed1994

Three types of liver cell dysplasia (LCD) in small cirrhotic nodules are distinguishable by karyometry and PCNA labelling, and their features resemble distinct grades of hepatocellular carcinoma.

We have studied the occurrence and specific features of liver cell dysplasia (LCD) in Chinese patients showing liver cirrhosis with or without hepatocellular carcinoma (HCC). Three types of LCD (SLCD, LLCDo, LLCDe) were morphologically defined, and these types were further analyzed using karyometry, estimation of nucleic acid content and density, and PCNA immunostaining. Features found for three types of LCD were compared with those of normal hepatocytes (NLC), simple regenerating hepatocytes (SRLC), and cells of HCCs covering different grades. The results show that 1) karyometry and nucleic acid parameters allow an objective separation of LCD types both from NLC and SRLC; 2) karyometric features of LLCDe are most close to those of highly differentiated HCCs, whereas nuclear size and chromatin composition of SLCD closely reflect those of poorly differentiated HCCs; 3) the frequency of LCD clusters was higher in cirrhotic livers carrying HCC, being about double for all three LCD types; 4) the highest PCNA labelling occurred in the small cell group of LCD (SLCD), still, however, being smaller than that of simple regenerating hepatocytes. Based on these findings it is suggested that, similar to atypical adenomatous hyperplasia, LCDs of distinct morphotypes may represent precursor lesions for HCC, and some cellular forms may mimick cell types known to occur in experimental carcinogenesis.

Carcinoma, Hepatocellular↗
PubMed1994

[Management of early avascular femur head necrosis by implantation of a muscle-bone graft].

Authors describe the results of 10 patients operated for avascular necrosis of the femoral head. The first operation was performed in October 1987. The follow-up was in average 41.9 (24-54) months, minimally 2 years. 7 patients improved, 2 deteriorated, 1 was unchanged. The analysis of the results showed that this operation is indicated only in strictly stated conditions.

Bone Transplantation↗
PubMed1994

[Ambulatory short-term therapy of anxiety patients with autogenic training and hypnosis. Results of treatment and 3 months follow-up].

The aim of the study was to examine the effects of a short-term outpatient treatment (6 sessions à 90 minutes) with autogenic training (Schultz 1932) or hypnosis (Erickson and Rossi 1979), concerning patients with anxiety- and panic disorders (according to DSM-III-R and ICD-10-criteria). 27 Outpatients were recruited by newspaper articles. Most of them had not been treated before. Both short-term treatments consisted of 6 weekly group sessions (4-6 patients). Psychological examinations were carried out before and after treatment and at a follow-up after 3 months. Trait anxiety (STAI-X2) and psychosomatic complaints (BfS/BL') decreased in both groups significantly after treatment. This therapeutic effect was stable during the following 3 months. The frequency of panic attacks decreased as well under treatment, and this effect was even more marked during the 3 month following treatment. The therapeutic success was influenced by the frequency of autosuggestive exercises carried out by the patients at home. This form of short-term treatment is not sufficient for all patients with anxiety disorders but the results of that study encourage to use short-term interventions with autogenic training and hypnosis as initial therapeutic approaches for such patients and to combine them with other therapeutic interventions.

Adult↗
PubMed1994

Late graft dysfunction after liver transplantation for primary biliary cirrhosis: disease recurrence versus chronic graft rejection.

Possible recurrence of primary biliary cirrhosis (PBC) in the transplanted liver has been reported. We discuss a case of presumed PBC recurrence after liver transplantation. However, the patient's full documented 9-yr follow-up after liver transplantation confirmed the diagnosis of chronic liver graft rejection instead of recurrent disease. This case report underlines not only the difficult differential diagnosis between recurrent PBC and chronic rejection, but it also stresses that complete follow-up, including strict morphological follow-up, is necessary before definitive conclusions can be drawn.

Diagnosis, Differential↗
PubMed1994

The pathology of the atrophy/hypertrophy complex (AHC) of the liver. A light microscopic and immunohistochemical study.

The term, atrophy/hypertrophy complex (AHC) of the liver, denotes a distinct combination of hepatic atrophy and hypertrophy occurring in situations of significant impairment of bile flow and/or portal or hepatic venous blood flow. In the lobes or segments concerned atrophy ensues, whereas areas not or less involved develop compensatory hypertrophy, resulting in a characteristic gross deformity of the organ and, in some instances, in rotation of the liver around a virtual hilar axis. As recognition and early detection of AHC have a strong implication on the treatment of several hepatobiliary diseases, adequate combined clinical, radiological and histopathological strategies have to be used in order to arrive at a correct diagnosis. The present investigation was designed to analyze the morphology of AHC in detail and to define lesion patterns having the highest predictive value. For atrophy, the following features were highly characteristic: 1) Advanced septal fibrosis with or without nodular change of parenchyma; 2) Biliary piecemeal necrosis with formation of vascular structures; 3) Ductular proliferations, frequently extending into septa and involving the parenchyma; 4) Capillarization of sinusoids with type IV collagen deposition in Disse's space; 5) Factor VIII-associated antigen expression by sinusoidal endothelia; 6) a seemingly paradoxical increase of proliferative activity of hepatocytes as based on PCNA staining. The severity of lesions in atrophy was related to the type of underlying disease, in that the changes were clearly more expressed in situations of longstanding obstruction due to benign disease. Using a set of well-defined morphological parameters, atrophy can be reproducibly distinguished from hypertrophy in biopsy material from AHC.

Adult↗
PubMed1994

[Management of early avascular femur head necrosis by flexion osteotomy. 2-year follow up].

Authors report on the results of treatment in 19 patients, operated for avascular necrosis of the femoral head. The first operation was performed in October, 1989. The average follow-up was 28 (24-42) months, the minimal follow-up 2 years. The state of one patient grew worse, one was unchanged, the rest improved. Operation in early cases is suggested if less than 50 per cent of the femoral head is attainted.

Femur Head Necrosis↗
PubMed1994

[MR-angiography in diagnosis and follow-up of therapy: arteria lusoria].

Diagnostic and therapeutic procedures are presented in a 29-year-old female patient who suffered from severe dysphagia and rapid loss in weight. In the conventional X-ray examination and barium swallow an aberrant right subclavian artery was suspected. MR imaging (MRI) and MR angiography (MRA) were done to plan the surgical correction. Postoperative MRA documented exactly the complex topography after surgical correction and the flow pattern in the implanted Gore-Tex stretch graft prosthesis. Non-invasive MR angiography renders possible the concrete planning of complex corrections of thoracic vessels replacing invasive catheter angiography.

Adult↗
PubMed1994

Primary biliary cirrhosis (PBC): antigen-presenting cells differ in their distribution in early and late stage PBC and involve the ductal, but not the ductular compartment.

We have studied the distribution patterns of antigen-presenting cells (APCs) in different stages of primary biliary cirrhosis (PBC). 58% of cases with early PBC (stages I and II) exhibited dendritic APCs (S-100+, HLA-DR+, KiMlp+) in bile duct epithelia. In contrast, APCs, were not detected in ductular proliferations occurring in late PBC (stages III and IV), but occurred in portal tracts and piecemeal necroses. There was a correlation between the presence of APCs and HLA-DR expression in bile ducts but, in contrast to former studies, we noted a heterogeneous ductal HLA expression. These observations support the hypothesis that: 1) APC distribution in PBC may change as a function of stage, involving hepatic parenchyma in late PBC; 2) ductular epithelia may not represent a target for immune attack, because APCs do not accumulate in these structures; and 3) HLA expression in bile ducts may be heterogeneous, suggesting one mechanism why bile duct destruction in PBC does not take place in a synchronous way.

Adult↗
PubMed1993

[Clinical significance and histological classification of atrophy/hypertrophy complexes of the liver].

Biliary, portal, biliary/portal and hepatovenous obstruction have been recognized as the etiological factors leading to the atrophy/hypertrophy complex (AHC) of the liver. From 1987 to 1990 30 patients were evaluated in our department with documented significant AHC of the liver. The evaluation of these patients was performed at an interdisciplinary meeting of surgeons, gastroenterologists, radiologists and hepatologists. All patients were studied in regard to clinical, radiological and gastroenterological investigations, intraoperative findings and histology. We present the diagnostic pathway, which included ultrasound in 29 patients as the first diagnostic step and 26 patients in whom computed tomography was added. In 21 patients hepato-iodide scintigraphy was performed, in 14 patients ERCP and angiography, and in 8 patients PTC. Etiologically we found in 12 patients a post-cholecystectomy stricture (PCS) in 12 patients, a tumour obstruction in 9 patients, different etiologies (Echinococcus, Budd-Chiari syndrome, primary biliary cirrhosis [PBC], Mirizzi-syndrome) in 9 patients and an unclear etiology in 4 patients. On the basis of our study we present a new histological classification of the AHC. Severe histological changes were prognostically worse, even in benign diseases. Therapy planning is always dependent on a very precise diagnostic pathway and early recognition of AHC is essential for the planning of therapy and for the prognosis of the disease.

Adult↗
PubMed1993

Late results in patients treated with pi-mesons for bladder cancer.

BACKGROUND: The treatment of bladder cancer with 60 converging pion beams was expected to have certain dose-distribution advantages with possibly fewer side effects than other high linear-energy-transfer (LET) radiation therapies, such as neutrons. RESULTS: Early results were promising: 20 of 24 (83%) evaluable patients with sessile invasive bladder carcinomas had clinically complete responses. However, only 3 of 10 (30%) evaluable patients with superficial bladder tumors had clinically complete responses. This article reports the long-term follow-up (6-8 years) of these patients with emphasis on the late side effects of pion radiation therapy. Thirty-eight of the 41 (93%) patients treated died after a median survival time of 17 months (range, 4-98 months). Seventeen (45%) died of metastatic disease (in two instances, this was combined with a local recurrence) 5-27 months after radiation therapy. Four (10%) died of locally progressive disease, and eight (21%) died of late side effects of radiation therapy 9-98 months after treatment. All these patients were treated with more than 33 pion Gy and had generally a symptom-free interval of 9-18 months. The observed side effects were severe, consisting of chronic inflammation and vascular damage in the pelvic region often followed by ulceration, fistulas, and perforations throughout the intestines. In 11 patients, cystectomy and urinary diversion was necessary because of excessive fibrosis and bladder shrinkage. In eight patients, a colostomy was required for stenotic inflammatory disease, necrosis, and perforations of the intestines. The remaining nine patients (24%) died of causes unrelated to the primary disease 4-60 months after radiation therapy. CONCLUSIONS: The results of the first Phase I/II trial using the Swiss piotron showed a high complete response rate in patients with sessile bladder cancers but also a high incidence of local recurrences and severe, in some instances lethal side effects. Although it is expected that these results will be the basis for future improvements, particularly regarding dosing and fractionation, this experience emphasizes the need for a sufficiently long observation period before reaching conclusions about any high LET treatment, such as neutron, pion, or heavy ion radiation therapy.

Adult↗
PubMed1993

Extended left hepatectomy: technical aspects of an evolving procedure.

Lessons learned in an operative experience of 14 patients submitted to extended left hepatectomy for the management of liver tumours are presented. There were no deaths within 30 days of operation. Essential preoperative studies, indications and technical details of the operation are described. The importance of the morphology of the tumour and the influence of the tumour on the technique to be adopted are emphasized. Modifications of technique that allow selection of patients for the procedure, control of venous bleeding, accurate identification of the sectorial portal pedicles within the right liver and definition of the plane of parenchymal transection are addressed.

Hepatectomy↗
PubMed1993

Pseudomonas aeruginosa promoters which contain a conserved GG-N10-GC motif but appear to be RpoN-independent.

The proC gene of Pseudomonas aeruginosa encodes the constitutive delta 1-pyrroline 5-carboxylate reductase (the third enzyme of proline biosynthesis) and ranks among the numerous Pseudomonas genes which are poorly transcribed in Escherichia coli. The promoters of the proC gene were located by deletion mapping. The 5' ends of the proC transcripts originating from one promoter were determined by primer extension. This promoter has a GG-N10-GC motif with a 16 bp spacing between the GC doublet and the transcription start site. Such spacing is unusually long for sigma 54-dependent promoters. In rpoN mutants of P. aeruginosa and P. putida a proC'--'lacZ fusion was expressed at wild-type levels, suggesting that sigma 54 RNA polymerase is not involved in proC transcription. The expression of another P. aeruginosa gene, anr (for anaerobic regulation of nitrate respiration and anaerobic arginine degradation), also appeared to be independent of RpoN in Pseudomonas and occurred at a very low level in E. coli. The proC and anr promoters have sequence similarities in addition to the conserved GG--N10--GC motif and may also be related to some alg (alginate) promoters of P. aeruginosa. We propose that the proC and anr promoters are activated by proteins, including perhaps an alternative sigma factor, which are present in Pseudomonas but absent from E. coli.

Base Sequence↗
PubMed1993

Visceral leishmaniasis after orthotopic liver transplantation: impact of persistent splenomegaly.

Visceral leishmaniasis was observed in a 50-year-old female liver transplant recipient 1 year following transplantation. Signs of active infection were low-grade fever, pancytopenia, persistent splenomegaly, positive cultures for leishmania in liver and bone marrow biopsy specimens, and newly positive leishmania serology. Following sequential therapy with pentavalent antimony and amphotericin B, blood values improved massively, bone marrow cultures became negative, and leishmania serology decreased. Secondary prophylaxis with fluconazole was instituted and the patient remains without signs of active infection 1 year after successful therapy.

Female↗