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Biomedical subjects

G Pistorius

Publications and source records attributed to G Pistorius.

At least 19 recordsLinked to original sources
PubMed2002

Comparison of surgical stress between laparoscopic and open colonic resections.

BACKGROUND: The magnitude of surgical trauma after laparoscopic and open colonic resection was evaluated by examining postoperative serum values of interleukin-6 (IL-6), IL-10, C-reactive protein (CRP), and granulocyte elastase (GE) for further evidence of the benefit realized with minimally invasive approaches in colonic surgery. METHODS: Altogether, 42 patients with Crohn's disease (n = 20) or colon carcinomas/adenomas (n = 22) were matched by age, gender, body mass index (BMI), and Crohn's Disease Activity Index for either a laparoscopic (n = 21) or an open colonic resection (n = 21). In both groups the postoperative serum levels of IL-6, IL-10, C-RP, and granulocyte elastase were determined, as indicators of surgical stress. RESULTS: Laparoscopic and open colonic resection caused a significant increase in serum IL-6, IL-10, CRP, and granulocyte elastase levels. The comparison between laparoscopic and open colonic resections, however, showed significantly lower serum IL-6, IL-10, CRP, and granulocyte elastase levels after laparoscopic colonic resection, which was most evident for IL-6 and granulocyte elastase. CONCLUSIONS: Our study demonstrated that IL-6 and granulocyte elastase may be appropriated particularly to monitor surgical stress. By using these parameters, we found a significant reduction in surgical trauma after laparoscopic surgery, was compared with the open procedure. This supports the clinical findings of a clear benefit for patients undergoing laparoscopic colonic surgery.

Adult↗
PubMed2002

Unusual case of a large midoesophageal diverticulum mimicking unstable angina pectoris.

We describe a 77-year-old lady who presented with progressive retrosternal pain radiating to the left arm and the back. After exclusion of cardiac causes a large midoesophageal diverticulum was found on oesophago-gastro-duodenoscopy. Importantly, the retrosternal pain completely disappeared after endoscopic removal of impacted food from the diverticulum. After the surgical resection the patient became fully asymptomatic. This is the first example of angina-like chest pain which definitively resulted from a midoesophageal diverticulum. Therefore, midoesophageal diverticula should be considered as a rare differential diagnosis of exercise-induced retrosternal pain.

Aged↗
PubMed2002

Expression of CD44v6 has no prognostic value in patients with colorectal cancer.

BACKGROUND AND AIMS: In colorectal cancer patients' mortality is largely influenced by spreading of tumour cells from the primary tumour site and subsequent metastasis formation. CD44 is an adhesion molecule and represents a highly variable family of isoforms. The isoform CD44v6 has been associated with metastatic spread and poor prognosis in animal models and several human cancers. Results of immunohistological studies in primary colorectal cancer are mostly retrospective and contradictory. The aim of our prospective study was to assess the controversial role of CD44v6 as a prognostic factor in colorectal cancer. METHODS: In 93 patients we analysed tumour CD44v6 expression in prospectively sampled stage I-IV colorectal adenocarcinomas using RT-PCR and Southern blotting. The prognostic value of the CD44v6 expression was assessed using univariate and multivariate analysis. RESULTS: CD44v6 expression was found in 47 % of the cases. CD44v6 expression failed to show any association with the clinical or histological variables examined. CD44v6 expression did not correlate with survival in long-term follow-up. The most important prognostic factor in this cohort was tumour stage. CONCLUSIONS: Changes in CD446 expression level do not predict tumour spread or patient survival in colorectal cancer.

Adenocarcinoma↗
PubMed2001

Stage-specific alternative cplicing of CD44 and alpha 6 beta 1 integrin in colorectal tumorigenesis.

Recent reports suggest that cancerogenesis induces changes in alternative processing of human genes. However, little is known about the regulation of alternative splicing during malignant transformation. Therefore, we examined changes in alternative splicing of two different adhesion molecules, alpha 6 beta 1 integrin and CD44, in multiple stages of colon tumorigenesis. Using semiquantitative RT-PCR it is shown that the alternatively spliced isoforms of both adhesion molecules, alpha 6A and -B and CD44v6, are significantly upregulated in colorectal adenoma (n = 20) compared to normal colon mucosa (n = 32) (P < 0.01). Although beta1 isoforms were expressed in almost all tissues, there was a significant increase in the intensity of gene expression of beta 1A compared to beta 1B (P <0.05) in adenoma tissue. Interestingly, CD44v6 and alpha 6 variant isoforms were downregulated in carcinoma tissue (n = 28) compared to adenoma. These results establish a link between neoplastic transformation and alternative splicing of cell adhesion molecules. Furthermore, these data suggest that colon epithelial cells carrying splice variants of adhesion molecules might acquire a selective growth advantage during early tumorigenesis.

Adenocarcinoma↗
PubMed2001

Lymphangioma of the pancreas and the duodenal wall: MR imaging findings.

Pancreatic lymphangiomas are rare benign tumours with a histogenesis not yet completely understood. Predominantly the cystic aspect of this lesion can complicate the differentiation from other neoplastic and non-neoplastic cystic tumours of the pancreas. We present a case of a middle-aged woman with a lymphangioma involving the duodenal wall and the pancreatic head. With special regard to MR imaging findings differential diagnosis is discussed.

Adult↗
PubMed2001

Increased matrix metalloproteinase 2 concentration and transcript expression in advanced colorectal carcinomas.

Colorectal cancer is one of the most common malignant tumors and entails a relatively poor prognosis. Clinical outcome depends on the extent of local and metastatic tumor spread. Results of in vivo and in vitro studies suggest that the balance between matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases TIMPs) is altered in neoplasia, contributing to the invasive and metastatic properties of malignant tumors. We quantified tissue concentrations of MMP-2 and TIMP-2 in 65 malignant colorectal lesions and corresponding normal mucosa by enzyme-linked immunosorbent assay, western blotting, and in situ hybridization. In situ hybridization and western blot analyses demonstrated a clear increase in both stromal expression of MMP-2 transcripts and protein in primary carcinomas. The protein concentration of MMP-2 was higher in all tumor stages, except stage I tumors, than in normal mucosa and adenomas. MMP-2 concentrations were not related to tumor differentiation or to colonic versus rectal location. Surprisingly, the MMP-2 concentration was not increased in metastases. Interestingly, tissue concentrations and epithelial mRNA expression of TIMP-2 decreased significantly in primary colorectal cancer (UICC stages III and IV) but increased in metastases. Therefore an increased ratio of MMP-2 to TIMP-2 is strongly associated with advanced tumor stages, but a decreased ratio was observed in metastases. These findings suggest that the MMP-2:TIMP-2 ratio may prove useful as a marker of local invasion but not of metastasis in colorectal cancer.

Blotting, Western↗
PubMed2001

Alternative shift models and the quality of patient care. An empirical study in surgical intensive care units.

UNLABELLED: On 1 January 1996, the German Arbeitszeitgesetz (working-time regulation) came into effect for hospital physicians. It states that working hours must not exceed 8 h per day, even for physician in hospitals. As a consequence, the prevalent two-shift model is legally inadmissible. The intention of this law is to protect the physician and to create better conditions for the patients. However, a systematic evaluation of the postulated benefits is still lacking. AIM: The aim of our study was to analyze the influence of the length of daily working hours on the quality of patient care by measuring the outcome of patients in intensive care units (ICUs), comparing the two-shift model (2-SM)--two 12-h shifts--with the three-shift model (3-SM)--three 8-h shifts. MATERIALS AND METHODS: In a prospective multicenter study, we compared the outcome of patients in six ICUs (organized by surgeons) with different models of working hours. The health status of each patient and the course on ICU [described by hospital mortality, number of complications, readmission to the ICU, reinterventions, duration of the stay in an ICU and hospital, the course of the Acute Physiology and Chronic Health Evaluation (APACHE) II score] were uni- and multivariately analyzed. In addition, the technical and personnel resources of the ICUs and the hospitals were documented. RESULTS: Three hundred and forty seven patients (103 2-SM, 244 3-SM) were included. The epidemiological and the health status on admission to the ICU were comparable. Patients in the 3-SM stayed 1.6 days longer on ICU and 2.3 days longer in the hospital than the 2-SM patients. The frequency of complications, reinterventions, and readmissions to ICU was higher in the 3-SM. The median of the APACHE-II score decreased more for 2-SM than for 3-SM patients. This means a significantly quicker recovery of the patients in 2-SM (P < 0.05). The multivariate analysis with individual outcome measures as dependent variables revealed a significant positive effect of the 2-SM on the physicians' assessment of postoperative course, on the relative frequency of therapeutic procedures, and to a lesser extent on the duration of stay in the ICU.

APACHE↗
PubMed2000

Complete shutdown of microvascular perfusion upon hepatic cryothermia is critically dependent on local tissue temperature.

Since microvascular dysfunction with complete circulatory arrest and, thus, prolongation of tissue ischaemia is considered a potential mechanism for cell necrosis following hepatic cryosurgery, we determined the temperature necessary for induction of complete nutritive perfusion failure in cryothermia-treated rat livers. After localization of the cryoprobe with seven thermocouples and application of a single or double freeze-thaw cycle, in vivo fluorescence microscopy of the cryoinjured left lobe was performed over a 2-h period using a computer-controlled stepping motor, which guaranteed analysis of the identical liver tissue segments with exact allocation of the thermocouples and thus determination of tissue temperature. Cryothermia resulted in a central non-perfused part of injury, surrounded by a heterogeneously perfused peripheral zone. The non-perfused area after single and double freezing continuously increased over the first 90-min period due to a successive shutdown of perfusion within the peripheral border zone. Analysis of the thermocouples' temperature at the end of freezing revealed the 0 degrees C-front at 11.7 mm (single freeze-thaw cycle) and 12.1 mm (double freeze-thaw cycle) distant from the centre of the cryoprobe, which exactly corresponds with the initial (30 min) expansion of the area with nutritive perfusion failure. The increased non-perfused tissue area at 2 h conformed a critical border temperature between 8.29 +/- 1.63 degrees C and 9.07 +/- 0.24 degrees C. From these findings, we conclude that freezing of liver tissue to temperatures of at least < 0 degrees C causes complete/irreversible perfusion failure, which consequently will result in cell death and tissue necrosis, and may thus be supposed as a prerequisite for the safe and successful application of cryosurgery in hepatic tumour ablation.

Animals↗
PubMed2000

Establishment of an immunocompetent nipple valve anastomosis to prevent faecal reflux after ileocolic resection in dogs.

OBJECTIVE: To construct an immunocompetent nipple valve anastomosis (NVA) to exclude faecal reflux and compare it with an end-to-end anastomosis to see if it would prevent recurrent inflammation caused by intraluminal bacterial antigens in Crohn's disease. DESIGN: Laboratory study. SETTING: Teaching hospital, Germany. ANIMALS: Two groups of six beagle dogs each of which had NVA or end-to-end anastomosis. INTERVENTIONS: Construction of a NVA by stapling the telescoped nipple, and replacing the ileal mucosa on the valve by colonic mucosa; end-to-end anastomosis. MAIN OUTCOME MEASURES: Radiological, bacteriological, angiographic, and morphometric results. RESULTS: Absolute retrograde pressure-competence and free orthograde permeability of the NVA resulted in significantly lower intestinal bacterial counts compared with the end-to-end anastomosis (p < 0.05). Transposition of colonic mucosa was successful as demonstrated by revascularisation from the ileal nipple and looked normal on morphometry. CONCLUSION: If NVA were constructed in patients with Crohn's disease, recurrences should be prevented, which would verify the immunopathogenetic hypothesis of new inflammation.

Anastomosis, Surgical↗
PubMed1999

[Late onset of heparin-induced thrombocytopenia with recurrent arterial thromboses and amputation].

HISTORY: An 80-year-old woman had been hospitalized in a psychiatric clinic where, on the 22nd day, she sustained a fracture of the neck of the left femur, which was treated by internal screw fixation. The postoperative course was at first without complication. But 9 days postoperatively her platelet count had fallen to 59,000/microliter. As heparin induced type II thrombocytopenia (HIT II) was suspected, the thrombosis prophylaxis with low-molecular heparin was replaced by sodium danaparoid (twice 750 units subcutaneously). Despite this, ischaemia of the right lower leg developed and required amputation. On the following day the left lower leg and foot also became ischemic, where upon she was admitted to the author's hospital (37 days after her admission to the psychiatric clinic). ADMISSION FINDINGS: The patient was in a reduced general condition (body-mass index 19.5 kg/m2). She was disoriented as to place and time. Her blood pressure was 140/80 mmHg, her pulse irregular with a ventricular rate of 100/min. The skin below the middle of the left lower leg was cold and livid and the pedal pulses were not palpable. LABORATORY TESTS: Haemoglobin content was 9.7 g/dl, the white cell count 9,200/microliter, and platelet count 54,000/microliter. Electrolytes and creatinine were within normal limits. TREATMENT AND COURSE: Thrombendarterectomy was performed once via the left groin under danaparoid anticoagulation. There was no re-occlusion and the patient was able to walk again.--It was ascertained subsequently, she had already been given ordinary heparin in the psychiatric clinic for 20 days. Her platelet count of around 70,000/microliter returned to normal even though heparin administration was continued. CONCLUSION: A reduction in platelet count by more than half during heparin treatment suggests heparin-induced thrombocytopenia, in which case heparin should be discontinued at once. In high-risk patients adequate treatment should be initiated with other anticoagulants even before the occurrence of thromboembolism.

Aged↗
PubMed1999

Epi-illumination fluorescent light microscopy for the in vivo study of rat hepatic microvascular response to cryothermia.

To elucidate the hepatic microvascular response to cryothermia, we studied the liver microcirculation of Sprague-Dawley rats after one and two 4-minute freeze-thaw cycles using intravital fluorescence microscopy. Irrespective of the number of freeze-thaw cycles applied, the nature of hepatic microvascular injury was characterized by complete stasis of sinusoidal blood flow within the central part of the cryolesions and heterogeneous sinusoidal perfusion in a critically perfused border zone located at the periphery of the lesions. Analysis over time (2 hours) revealed a successive shutdown of sinusoidal perfusion within this critically perfused border zone, which was caused by intravascularly lodging cell aggregates, blocking the lumen of individual sinusoids. The aggregates consisted of parenchymal cells and cell fragments, but did not include leukocytes or platelets. Strikingly, microvascular perfusion failure was associated with Ito cell disintegration and marked dilation of sinusoids (15.6 +/- 0.8 microm vs. 8.8 +/- 0.8 microm; P <.05). This excludes sinusoidal constriction as the cause of nutritive perfusion failure, and may indicate dysfunction of Ito cell-regulated vasomotor control by cryothermia. However, because circulating cell aggregates were frequently observed plugging individual microvessels, dilation of sinusoids may just be the result of passive distension caused by outflow blockade. Analysis of hepatic tissue at 8 weeks after cryothermia did not reveal regeneration and microvascular remodeling, but loss of hepatic tissue, which corresponded well with the tissue area presenting with sinusoidal perfusion failure during the initial observation period after cryothermia. The fact that there was no recovery of sinusoidal perfusion over the initial 2-hour observation period, but loss of tissue after 8 weeks, supports the view that cryothermia induces injury not only by direct low-temperature-mediated action, but also through ischemia caused by irreversible deterioration of the microcirculation.

Animals↗
PubMed1999

Granulocyte elastase and systemic cytokine response after laparoscopic-assisted and open resections in Crohn's disease.

PURPOSE: The aim of this study was to assess whether systemic proinflammatory cytokines (IL-6), anti-inflammatory cytokines (IL-4, IL-10), acute phase proteins (C-reactive protein), or granulocyte elastase are valuable indicators for determining the degree of surgical trauma after open vs. laparoscopic-assisted resections in Crohn's disease. METHOD: Eleven patients in each group (open and laparoscopic-assisted surgery) were matched for indication, surgical procedure, and Crohn's disease activity index. Serum IL-4, IL-6, and IL-10 were measured using enzyme-linked immunosorbent assay. Serum C-reactive protein was determined by immunoturbidimetric assay. Plasma granulocyte elastase was determined by immunoactivation immunoassay. Blood was sampled preoperatively, six hours after the operation, and at postoperative Days 1 to 5. RESULTS: IL-4 was not detectable in any sample analyzed. Serum IL-6 and IL-10 levels peaked postoperatively in both groups without significant differences between laparoscopic-assisted (185.6 +/-54.1 pg/ml and 112.1 +/- 19.4 pg/ml, respectively; mean +/-standard error of the mean) and open surgery (431.1 +/-240.4 pg/ml and 196.7 +/- 56.5 pg/ml, respectively). Serum C-reactive protein levels also rose postoperatively, with a peak on the second day, but showed similar values after laparoscopic-assisted (107.1 +/- 12.1 mg/l) and open (128.3 +/- 17.5 mg/l) surgery. Plasma granulocyte elastase levels peaked on the first and second postoperative day and were found elevated almost throughout the five-day observation period. Comparison between the groups revealed significantly (P < 0.02) lower values after laparoscopic-assisted (Day 1, 46.5 +/- 8.9 microg/l; Day 2, 41.9 +/- 5.9 microg/l) when compared with open surgery (Day 1, 89.7 +/- 13.8 microg/l; Day 2, 91.4 +/- 14). CONCLUSIONS: Serum IL-6 and IL-10 may not be ideal measures for evaluation of the degree of tissue trauma in laparoscopic-assisted and open resections in Crohn's disease, probably because of interference with disease-specific cytokine interactions. In contrast, granulocyte elastase has to be considered a strong marker discriminating the different severity of surgical trauma induced by laparoscopic-assisted vs. open resection in Crohn's disease.

Adult↗
PubMed1999

[Cryosurgery--renaissance or real progress?].

The development and improvement of the cryosurgical technique in combination with intraoperative ultrasonographic imaging enables reliable destruction of liver tumors--although not free of complications--given that tried and tested rules of cryosurgical research are obeyed. In this respect, we can speak of real progress. On the basis of a 3-year testing phase with the CRYO6 cryosurgical apparatus from ERBE, a protocol for the cryosurgical technique for liver tumors is introduced. The spectrum of indications for cryosurgery includes the destruction of irresectable hepatic secondaries or primary tumors with curative intention and the freezing of insufficient or incomplete resection margins. The preliminary results of this treatment modality are encouraging. However, there remains a need for further clinical research to allow final judgement of the cryosurgical method.

Clinical Trials as Topic↗
PubMed1999

Effectiveness of a hands-on training course for laparoscopic spine surgery in a porcine model.

BACKGROUND: Although it is widely proposed that surgeons, before introducing a novel laparoscopic technique in man, should practice in an appropriate animal model for acquisition of the necessary technical skills, the effectiveness of those hands-on training courses are rarely documented. METHODS: In 1995 we have organized eight hands-on training courses for laparoscopic anterior interbody spine fusion in an in vivo porcine model. A total of 72 colleagues from 50 different centers of 12 countries participated, including orthopedic, trauma, visceral, neuro-, and vascular surgeons. Quality and effectiveness of the course were evaluated by a questionnaire after a 1.5- to 2.5-year period. RESULTS: During this time, 42.2% of the participating centers had applied the new technique successfully in man. Centers which participated in the course with a team that included a skilled laparoscopic surgeon and an orthopedic or trauma surgeon introduced the technique more frequently to clinical practice (57.9%) than those represented by only one participant (30. 8%). Moreover, there was a tendency toward a more frequent introduction of the technique to clinical practice in centers associated with university hospitals (57.1% vs. 29.2%), indicating the requirement of a particular infrastructure for this complex interdisciplinary procedure. Almost all participants (98.3%) agreed that for novel surgical techniques requiring advanced technical skills, there should first be training in a large animal model before the technique is applied in man. CONCLUSIONS: Complex laparoscopic procedures (i.e., laparoscopic spine surgery) can be successfully learned by in vivo hands-on training courses. We propose that for refinements and modifications of the technique (e.g. , the lumboscopic approach), there should also first be training in a large animal model before these are applied in man.

Animals↗
PubMed1998

The electronic patient record in general practice--a South-African perspective.

A research project was undertaken to design an electronic medical record system which will cater for the specific needs of South African general practitioners and their unique requirements. The project was launched by sending out a questionnaire to general practitioners in the Free State, trying to determine their specific requirements and to gain insight into their attitudes and opinions regarding the use of computers, especially the computer-based patient record, in a general practice setting. The results indicated that there was a need to replace the current manual patient record with an electronic version, and that the attitudes of the general practitioners in South Africa were generally favourable regarding implementing and using such a system. Given these results, we can proceed to design a computer-based patient record system, specifically addressing the needs and requirements of the South African general practitioner.

Attitude to Computers↗