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Biomedical subjects

M Kraemer

Publications and source records attributed to M Kraemer.

At least 37 records · Page 2Linked to original sources
PubMed2001

Stratifying risk factors for follow-up: a comparison of recurrent and nonrecurrent colorectal cancer.

INTRODUCTION: The selection of patients for individualized follow-up and adjuvant therapy after curative resection of colorectal carcinoma depends on finding reliable prognostic criteria for recurrence. However, such criteria are not universally accepted, and follow-up is often standardized for all patients without regard for each individual's level of risk of recurrence. Such a system of follow-up is not cost-effective. METHODS: A comparison of operative findings, pathologic features, and follow-up data of 1,731 cases of nonrecurrent colorectal cancer (821 colon, 910 rectum) with 357 cases of recurrent colorectal cancer (164 colon, 193 rectum) following potentially curative surgery was made, and results were analyzed to ascertain criteria for stratifying follow-up according to risk factors. RESULTS: Single-factor analysis showed that Dukes staging and tumor invasion were significantly associated with recurrence in both rectal and colon carcinoma. Tumor fixation and grading were additional significant factors in rectal cancer. Recurrence rates, time to recurrence, site of recurrence (locoregional vs. distant), and pattern of metastatic spread were not significantly affected by original tumor site. Recurrence was not significantly affected by patient age and gender. Individual surgeon performance in this series had also no significant effects on tumor recurrence. With multivariate analysis only, Dukes staging and tumor invasion into adjacent tissues were found to be independent adverse prognostic factors for recurrence. CONCLUSIONS: Dukes staging and tumor penetration into adjacent tissues are the only significant adverse prognostic factors for tumor recurrence of colonic and rectal carcinoma. Tumor grade and tumor fixation are additional adverse prognostic factors in rectal cancer. Guidelines for follow-up may be based on these factors and follow-up thus stratified according to risk of developing recurrence.

Adult↗
PubMed2001

Could 99mTc-MIBI be used to visualize the apoptotic MCF7 human breast cancer cells?

Defects in key components of apoptotic pathways provide a survival advantage to cells and have been implicated as important factors in tumorogenesis. As therapeutic drug-induced apoptosis is a key component in treatment of most cancers, alterations in apoptotic pathways may be critical to drug resistance. The question is: would it be possible to distinguish apoptotic cells and resistant cells with a same radiotracer? In this study, we investigated the ability of sodium phenylacetate (NaPa), a natural cytostatic proapoptotic metabolite, to induce apoptosis in MCF7 human breast cancer cells. Then, we tested the 99mTc-MIBI accumulation in these apoptotic cells. Annexin V-FITC was used to identify apoptotic cells by flow cytometry. Ours results demonstrated that a 72 hr treatment of MCF7 cells with 40 mM NaPa induced apoptosis in 60% of cells. In a parallel way, 99mTc-MIBI accumulation in NaPa treated cells decreased for concentrations higher than 20 mM NaPa. Thus, 99mTc-MIBI accumulation decreased correlatively with the increasing percentage of apoptotic cells obtained by treatment of MCF7 cells with NaPa. These data demonstrate that NaPa induced apoptosis in MCF7 cells and that 99mTc-MIBI is a negative tracer of apoptosis: the more MCF7 cells were engaged in the apoptotic pathway, the more 99mTc-MIBI accumulation decreased in these MCF7 apoptotic cells.

Apoptosis↗
PubMed2001

Subnormal visual acuity syndromes (SVAS): albinism in Swedish 12-13-year-old children.

BACKGROUND: The vision of 12-13-year-olds in Sweden was examined in a field study. The study was designed as being a part of a large European-Latin American study, the DESAMI project. The objective was to evaluate the prevalence of residual amblyopia and ocular disorders, atiologies of subnormal vision and some normal visual parameters in this group of children. The children had to be born in Sweden in 1985 in order to have the opportunity to be included in the voluntary screening visual examinations. The full results of the study will be presented elsewhere. This paper presents clinical and VEP data of those children who had visual acuity of 0.8 or below in one or both eyes which could not be increased with glasses, or other visual/eye disturbances not explained as common amblyopia, i.e., subnormal visual acuity or pathological visual states of unknown cause, SVAS (subnormal visual acuity syndromes). SUBJECTS AND METHODS: In all, 1046 children were examined: 76 had visual disturbances of such severity that they were referred to a paediatric ophthalmologist (AS). Eighteen children could not be pathologically classified, and they were referred to another ophthalmological examination and VEP (visual evoked potential) recordings. VEP reveals an asymmetric response after monocular stimulation in albinism. RESULTS: Twelve children turned up for a second examination and VEP was recorded from 10 children. Nine children showed iris translucency. Seven children showed an asymmetric VEP and were classified as albinos. The albinoic VEPs could be subdivided into two types, (1) including all parts of the response and (2) partly excluding the P1/P100 potential complex. The VEP response was normal, showing symmetry and no other abnormality, in three of the children. CONCLUSIONS: The results indicate that albinism is common in Sweden. A prevalence value of approximately 1% is about 100 times higher than previous figures. This high prevalence may indicate another form of heredity, with genetical contribution to albinism from a varying number of albino genes and varying expression in the phenotypes, in the Scandinavian population. It is emphasised that in investigations of children with SVAS, electrophysiological examinations are important, not only to reveal albinism but also to exclude or verify neurometabolic conditions, for example.

Adolescent↗
PubMed2001

Experimental evaluation of a cell module for hybrid liver support.

Aim of the study was to evaluate a hybrid liver support system in a porcine model of acute liver failure, after hepatectomy. Pigs with a body weight of 70+/-18 kg underwent total hepatectomy and porto-cavo-caval shunting as well as ligation of the bile duct and the hepatic artery. Control animals were connected to the system (including capillary membrane plasma separation) containing a four compartment bioreactor with integral oxygenation and decentralized mass exchange but without liver cells. The treatment group received hybrid liver support with the same system including 370+/-42 g primary isolated porcine parenchymal liver cells in co-culture with hepatocyte nursing cells, tissue engineered to liver- like structures at high density. Treatment started after complete recovery from anesthesia and was performed continuously. A positive influence on peripheral vascular resistance and a reduced need of catecholamine dosage was observed in the treatment group. Hybrid liver support with a cell module upscaled for clinical application significantly prolonged survival time in animals after hepatectomy with the longest survival being 26 hours in the control group an 57 hours in the treatment group.

Animals↗
PubMed2001

Subnormal visual acuity syndromes (SVAS): albinism in Swedish 12-13-year-old children.

BACKGROUND: The vision of 12-13-year-olds in Sweden was examined in a field study. The study was designed as being a part of a large European-Latin American study, the DESAMI project. The objective was to evaluate the prevalence of residual amblyopia and ocular disorders, aetiologies of subnormal vision and some normal visual parameters in this group of children. The children had to be born in Sweden in 1985 in order to have the opportunity to be included in the voluntary screening visual examinations. The full results of the study will be presented elsewhere. This paper presents clinical and VEP data of those children who had visual acuity of 0.8 or below in one or both eyes which could not be increased with glasses, or other visual/eye disturbances not explained as common amblyopia, i.e., subnormal visual acuity or pathological visual states of unknown cause, SVAS (subnormal visual acuity syndromes). SUBJECTS AND METHODS: In all, 1046 children were examined: 76 had visual disturbances of such severity that they were referred to a paediatric ophthalmologist (AS). Eighteen children could not be pathologically classified, and they were referred to another ophthalmological examination and VEP (visual evoked potential) recordings. VEP reveals an asymmetric response after monocular stimulation in albinism. RESULTS: Twelve children turned up for a second examination and VEP was recorded from 10 children. Nine children showed iris translucency. Seven children showed an asymmetric VEP and were classified as albinos. The albinoic VEPs could be subdivided into two types, (1) including all parts of the response and (2) partly excluding the P1/P100 potential complex. The VEP response was normal, showing symmetry and no other abnormality, in three of the children. CONCLUSIONS: The results indicate that albinism is common in Sweden. A prevalence value of approximately 1% is about 100 times higher than previous figures. This high prevalence may indicate another form of heredity, with genetical contribution to albinism from a varying number of albino genes and varying expression in the phenotypes, in the Scandinavian population. It is emphasised that in investigations of children with SVAS, electrophysiological examinations are important, not only to reveal albinism but also to exclude or verify neurometabolic conditions, for example.

Adolescent↗
PubMed2000

Identification of a peptide blocking vascular endothelial growth factor (VEGF)-mediated angiogenesis.

Vascular endothelial growth factor (VEGF) binding to the kinase domain receptor (KDR/FLK1 or VEGFR-2) mediates vascularization and tumor-induced angiogenesis. Since there is evidence that KDR plays an important role in tumor angiogenesis, we sought to identify peptides able to block the VEGF-KDR interaction. A phage epitope library was screened by affinity for membrane-expressed KDR or for an anti-VEGF neutralizing monoclonal antibody. Both strategies led to the isolation of peptides binding KDR specifically, but those isolated by KDR binding tended to display lower reactivities. Of the synthetic peptides corresponding to selected clones tested to determine their inhibitory activity, ATWLPPR completely abolished VEGF binding to cell-displayed KDR. In vitro, this effect led to the inhibition of the VEGF-mediated proliferation of human vascular endothelial cells, in a dose-dependent and endothelial cell type-specific manner. Moreover, in vivo, ATWLPPR totally abolished VEGF-induced angiogenesis in a rabbit corneal model. Taken together, these data demonstrate that ATWLPPR is an effective antagonist of VEGF binding, and suggest that this peptide may be a potent inhibitor of tumor angiogenesis and metastasis.

Amino Acid Sequence↗
PubMed2000

Tuberculous anal sepsis: report of clinical features in 20 cases.

INTRODUCTION: Tuberculosis is a neglected cause of anal sepsis, often is not recognized, and therefore is not treated properly. METHOD: All patients were reviewed who had tuberculous anal sepsis diagnosed by histology reports of fistulectomy specimens or abscess scrapings from January 1990 to April 1999. RESULTS: Twenty patients (median age, 53 years; 18 males) with anal tuberculous sepsis were identified. They presented with abscesses (n = 2), abscesses and fistulas (n = 6), or fistulas (n = 12). All patients had a long history of anal complaints (3 months to 20 years), for which 15 patients were operated on previously. Nearly all fistulas (17/18) were complex, and secondary tracks or additional complicating features were common, even at first presentation. Eight patients had active concurrent pulmonary tuberculosis, and six showed evidence of previous pulmonary tuberculosis. Six patients had no signs of concurrent or previous tuberculosis elsewhere. Recurrence was observed only in cases where tuberculosis was initially not recognized, and antitubercular treatment therefore was not started. CONCLUSION: Contrary to views held previously, anal tubercular sepsis seems to have characteristic clinical features. It should be considered in cases of known pulmonary or extrapulmonary tuberculosis or if anal sepsis is persistent, recurrent, or complex in nature.

Adult↗
PubMed2000

Acute appendicitis in late adulthood: incidence, presentation, and outcome. Results of a prospective multicenter acute abdominal pain study and a review of the literature.

BACKGROUND: Acute appendicitis is the second most common cause of surgical abdominal disease in late adulthood. It is a serious condition: major errors in management are made frequently and the condition is associated with significant morbidity and mortality. Data collected within a multicenter prospective trial and a literature review were used to analyze diagnostic and therapeutic difficulties in detail. METHODS: In a multicenter intervention study (MEDWIS A 70) data from 2,280 patients with acute abdominal pain were collected prospectively. Patients with histologically proven acute appendicitis, aged 50 years and older (n=102), were compared with younger patients (n=417) to determine differences in presentation, clinical course, and outcome. The basis for the literature review was a Medline search for appendicitis in late adulthood and in the elderly, covering the years 1980-1998. In addition, studies on clinical presentation of acute appendicitis in all age groups were also reviewed and appropriate data were extracted. RESULTS: Patients aged 50 years and older with acute abdominal pain had a significantly higher incidence of surgery. Fourteen percent had acute appendicitis (27% in younger patients), with an increased complication rate (20% vs. 8%) and mortality (3% vs. 0.2%). Significantly more signs and symptoms suggestive of acute abdominal disease and peritonitis were recorded among older patients, reflecting the higher perforation rate (35% vs. 13%). Clinical presentation of appendicitis in younger patients was far more ambiguous. There were no significant differences in outcome between older and younger patients as regards perforations. Perforations are directly associated with treatment delay. Overall delay is a result of late presentation of older patients to hospital and postadmission delay. CONCLUSIONS: Appendicitis in late adulthood is characterized by a delay in treatment, high perforation rates, and unfavorable outcome parameters, all mutually correlating. Older patients with acute abdominal pain are high-risk patients, unlike their younger counterparts. They have to be clinically evaluated by experienced surgeons within a narrow time margin. The problem of late presentation and/or referral should be addressed, perhaps by education of primary care physicians and the public.

Abdomen, Acute↗
PubMed2000

Macroscopic assessment of the appendix at diagnostic laparoscopy is reliable.

BACKGROUND: Healthy-looking appendixes are often removed at laparoscopy for suspected appendicitis. This practice may have adverse secondary effects. METHODS: We reviewed the literature for the years 1978 to 1998 to analyze the negative appendectomy rates, complication rates, the accuracy of laparoscopic appendix assessment, and the incidence of false negative diagnosis of appendicitis at surgical and gynecological laparoscopy. RESULTS: The respective negative appendectomy rates were 22% and 15% in studies that compared laparoscopic with open appendectomy. The appendix was left in situ in 37% of 4,281 surgical diagnostic laparoscopies. There were instances of missed appendicitis among the 3,367 gynecological diagnostic laparoscopies performed on women for lower abdominal pain, and there were 188 appendectomies in this group. Studies comparing the macroscopic appearance of the appendix at operation with microscopic findings from the excised specimen had a false negative error rate of 3%. CONCLUSIONS: Contrary to general opinion, there is no substantial evidence to support the assumption that the macroscopic diagnosis of appendicitis is unreliable. High rates of conflicting diagnoses of excision specimens suggest that endoappendicitis has little clinical significance. At present, negative appendectomy rates are considerably higher for laparoscopic appendectomy than for the open approach. The role of diagnostic laparoscopy in suspected appendicitis should be reconsidered. It may be useful in particular subgroups of patients, but it is no substitute for good clinical judgment. Furthermore, it is not always necessary to perform an incidental appendectomy.

Appendectomy↗
PubMed2000

Marginal integrity of large compomer Class II restorations with cervical margins in dentine.

OBJECTIVES: The aim of the present study was to investigate the marginal integrity of total-bond Dyract AP restorations in large Class II restorations with cervical margins in dentine. The efficacy of a new non-rinse conditioner and the effect of beveling the enamel margins were also studied. METHODS: Large MOD cavities with cervical margins located 1mm below the CEJ were prepared in 48 extracted human molars. Six groups (n=8) were filled using a total-bond technique with Spectrum TPH or Dyract AP or a sandwich technique with Dyract in combination with Spectrum TPH. For Dyract AP total-bond restorations, a new non-rinse conditioner was tested vs. a total-etch with 36% phosphoric acid in beveled and butt-joint cavities. After water storage for 21 days and thermocycling (2000x, 5-55 degrees C), replicas were produced for quantitative marginal analysis in the SEM. Afterwards, teeth were immersed in 0.5% basic fuchsin for 24h and dried. Percent dye penetration over the total margin length was analysed in three layers using a sequential grinding technique. Statistical analysis was performed with non-parametric tests and the Bonferroni correction for multiple comparisons at p<0.05. RESULTS: All restoration types showed microleakage. On cervical margins in dentine, Dyract AP restorations showed better marginal adaptation than Spectrum TPH total-bond restorations (marginal openings (MO), median 33.8 vs. 79.6%), but were inferior to Dyract/Spectrum TPH sandwich restorations (MO: 0. 0%). The non-rinse conditioner improved the marginal adaptation of Dyract AP restorations in dentine (MO: 4.7 vs. 38.4%, p=0.0206 for beveled cavities, 12.2 vs. 33.8%, p=0.0238, for butt-joint cavities) and yielded similar results in enamel margins provided that enamel margins were beveled. Beveling of enamel significantly reduced the occurrence of enamel microcracks. CONCLUSIONS: The use of a non-rinse conditioner in combination with Dyract AP may improve the marginal adaptation of Class II restorations compared to composite restorations. The sandwich technique with Dyract results in better marginal adaptation in cervical dentine compared to all other restorative techniques tested in this study. However, microleakage cannot predictably be prevented with the sandwich technique.

Acid Etching, Dental↗
PubMed1999

The neonatal development of the light flash visual evoked potential.

AIMS: To follow visual development longitudinally in the normal neonate using the flash visual evoked potential (VEP) and to find indications for a relationship between potential development and visual development. METHODS: Twenty healthy infants, born at term, were included in the study. Flash and patterned flash VEPs were used. The first VEP was recorded the day of birth or just postnatally, and succeeding recordings were performed the following weeks and months. RESULTS: The data revealed different types of VEP in the neonatal period suggesting great variability in visual function on the day of birth. In the early development a potential of long latency and duration preceded the development of a more compound potential of shorter latency. The two types of responses seemed to coalesce during early development; the first late response was attenuated and was eventually integrated in the more mature VEP. At approximately five weeks of age changes in the VEP were simultaneous with the development of responsive smiling and another visual behaviour of the infants. CONCLUSIONS: The results showed many similarities between the VEP development in infants and in immature animals. In developing animals geniculo-cortical and extra-geniculate visual afferent pathways evoke two types of VEPs similar to those recorded in the present study. The early responses were also similar to previous recordings from children with lesions in the geniculo-striatal pathway or primary cortex. Our interpretation of the results was that the human VEP also consists of responses evoked by afferents running both in geniculo-cortical and extra-geniculate pathways and that the two types of responses could be separated in the VEP in the neonatal period. These findings are important for our understanding of conditions with a delay in visual maturation, for example intracranial haemorrhages, hydrocephalus, pre/dys-maturity and 'idiopathic' delayed visual maturation.

Aging↗
PubMed1999

Perforating appendicitis: is it a separate disease? Acute Abdominal Pain Study Group.

OBJECTIVE: To find out whether perforated and unperforated appendicitis are separate diseases and can be distinguished clinically. DESIGN: Prospective multicentre study. SETTING: 11 departments of surgery in Germany and Austria. SUBJECTS: 519 patients over 6 years old who had histologically confirmed acute appendicitis between October 1994 and March 1996. MAIN OUTCOME MEASURES: Differences in history, clinical findings, lab results, clinical course and outcome. RESULTS: 92 of the 519 patients (18%) had perforated appendicitis. The following variables were shown by univariate analysis to be significantly more common in the group with perforated appendicitis: rigidity, reduced abdominal wall movement, abdominal distension, reduced bowel sounds (all p<0.001), pale skin (p<0.005), generalised abdominal tenderness, severe abdominal tenderness (both p<0.01), WCC > or =10(9)/L (p<0.05). By multivariate analysis the following variables were significantly more common in the group with perforated appendicitis: age over 50 years (p<0.0001); change in bowel habit and rigidity of the abdominal wall (both p = 0.001); generalised tenderness (p<0.01); male sex (p<0.01); and distended abdomen (p<0.05). Rectal examination failed to make the distinction. CONCLUSIONS: Perforated and unperforated appendicitis behave clinically like two different diseases. They can in most cases reliably be distinguished using clinical criteria alone. Although greater diagnostic accuracy may result in a higher rate of perforation, close observation and timely intervention will only marginally affect the outcome.

Adult↗
PubMed1999

Rat embryo fibroblasts transformed by c-Jun display highly metastatic and angiogenic activities in vivo and deregulate gene expression of both angiogenic and antiangiogenic factors.

The comparative tumorigenicity in rats and nude mice of cell lines derived from FR3T3 and transformed by either c-jun, ras, SV40 lt, or bovine papilloma virus type 1 (BPV1) oncogenes was investigated. c-Jun-transformed cells were as tumorigenic and metastatic as Ras-transformed cells. Latencies were short, and numerous pulmonary metastases were observed in all injected animals. In contrast, tumors induced by s.c. injection of SV40-transformed cells developed slower, and none of the animals who received injections i.v. presented with metastases. BPV1-transformed cells had an intermediate tumorigenic and metastatic activity. Microvessels present in the different tumors were revealed by immunostaining with Griffonia (Bandeiraea) Simplicifolia lectin 1. Tumors obtained with c-Jun-transformed cells exhibited more neovascularization than those induced by the other oncogenes. By comparison to FR3T3 cells or SV40- or BPV1-transformed cells, c-Jun-transformed fibroblasts repress the antiangiogenic thrombospondin-1 and SPARC genes, whereas we found that they express higher levels of gene expression of the angiogenic vascular endothelial growth factor. Finally, as compared with cells before passage in animals, thrombospondin-1, SPARC, and VEGF gene expression was also deregulated in cell lines isolated from primary tumors induced by BPV1-transformants. Our results indicate that the high transforming potential of c-Jun, evidenced as soon as transformation is established in vitro, correlates with deregulation of gene expression of both angiogenic and antiangiogenic factors leading to rapid neovascularization of tumors.

Animals↗
PubMed1999

[Endosonographic imaging of anal fistulas in infants].

Anorectal endosonography is established as a diagnostic tool in anorectal fistulas, today. Yet, there is still little experience with the use of this method in small children. We could visualize three intershincteric fistulas in children at an age of 6, 7 and 14 months. The procedure is well tolerated and even children under the age of one year can be examined with a special probe.

Contrast Media↗
PubMed1999

[Open surgical therapy of constipation].

This paper reviews diagnostic criteria, indications, and selection criteria for surgical therapy in chronic constipation. Special emphasis is laid on surgical therapy of pelvic outlet obstruction. Colonic resection may be considered as last surgical resort in those few cases where conventional therapeutic measures have been exhausted and an extensive diagnostic protocol based on clearly defined criteria has been followed. This may offer a justifiable therapeutic alternative only in cases where highly symptomatic and refractory colonic inertia (slow transit constipation) is confirmed, and associated outlet obstruction has been excluded.

Chronic Disease↗
PubMed1998

Coloanal J-pouch reconstruction following low rectal resection.

From an oncological point of view, a distal resection border of 2 cm is sufficient after deep anterior rectal resection and total mesorectal excision. This conclusion has led to extending the indications for ultradeep rectal resection in recent years. The classical end-to-end coloanal anastomosis, however, has been shown to be associated with several functional drawbacks, for example, increased stool urgency and in some cases incontinence, especially in the first 6-12 months after the operation. It was to improve these aspects that the coloanal pouch was introduced. In a pilot study we performed a coloanal pouch in 25 patients (median age 65 years, range 32-85). The coloanal pouch anastomosis was generally performed by a stapling device. A transanal hand-sewn anastomosis was performed in the section down to the sphincter level. Indications included rectal cancer, recurrent villous adenoma, and in one case recto-vaginal fistula. The pouch was also constructed by a linear stapling device, and its length was usually 5-7 cm. The level of the anastomosis averaged 2 cm above the dentate line. In 16 patients a protective ileostomy was also carried out. We observed four cases of anastomotic leak and in one an abscess. Results showed full continence after 6 months and in 85% after 1 year. Urgency was observed in four patients after 3 months, and in only one after 1 year. In summary, we obtained encouraging results for initiating a randomized trial in the future to confirm the advantages of this type of reconstruction after deep anterior rectal resection.

Adult↗
PubMed1998

[Country-wide survey of therapeutic procedures in hemorrhoids and anal fissure].

A survey among coloproctologists was performed to assess current therapeutic concepts for the treatment of hemorrhoidal disease and anal fissure. A total of 261 clinical and non-clinical proctologists participated, representing the entire range of therapies in hospital and practise. A wealth of widely differing, in some aspects contradictory concepts were recorded, leaving almost no subject entirely undisputed. There are controversies regarding the different therapeutic alternatives as well as indications for surgery and choice of operative procedure. Future research has to address the existing controversies in order to reach a higher degree of standardization in the therapy of these common proctological disorders.

Colorectal Surgery↗