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Biomedical subjects

F Harder

Publications and source records attributed to F Harder.

At least 37 records · Page 2Linked to original sources
PubMed2000

An evaluation of telemedicine in surgery: telediagnosis compared with direct diagnosis.

HYPOTHESIS: Telemedicine for real-time transmission of clinical documents and interactive remote telediagnosis allows accurate clinical application in surgery. DESIGN: Prospective cohort study in which 2 hospitals, 120 miles apart, were connected via integrated services digital network (ISDN) teleconferencing units, and each evaluated clinical cases in real time. SETTING: A tertiary care university hospital and primary care county hospital. PARTICIPANTS: Between May 1, 1998, and June 30, 1998, 112 patients undergoing digestive or endocrine surgery were evaluated by teletransmission (study group) and direct vision (control group). Diagnosis had to be known by the viewer, and either conventional magnetic resonance imaging or computed tomographic scans were available. MAIN OUTCOME MEASURES: Picture quality, organ structure, and pathologic finding viewed on telemedicine documents were evaluated by radiologists and surgeons blind to diagnosis. Accuracy of remote 128-kilobit (kb)/s transmission-rate diagnoses and results were compared with those obtained directly. RESULTS: Picture quality was "good" or "excellent" in 92.9% of transmitted documents and 95.5% of live images (P>.4). The target organ was always recognized, structure and pathologic finding were analyzable in 98.2% of transmitted documents and 99.1% of live documents, and fine structures were assessable in 89.3% of transmitted pictures and 95.5% of live pictures (P>.05). Diagnosis was made in 84.8% of transmitted cases and 93.8% of live cases (P = .02). CONCLUSIONS: Low bandwidth (128 kb/s) telemedicine application in surgery is reliable in evaluating remote cases. Loss of image quality through teletransmission occurred in 2.7% of cases, and diagnosis was not possible in 15.2% of transmitted vs 6.2% of live cases, suggesting factors other than technical quality (choice of radiological studies, additional clinical information required, etc). This underscores the importance of real-time interactive discussion during surgical teleconferences.

Cohort Studies↗
PubMed2000

Mechanisms of ischemic preconditioning in skeletal muscle.

BACKGROUND: Ischemic preconditioning (IP) (one or more cycles each consisting of a short period of ischemia and a short period of reperfusion, before the sustained ischemia) reduces ischemia-related organ damage in heart and skeletal muscle but the underlying mechanisms are not clear. This study was intended to assess the possible involvement of K(ATP) channels and of adenosine receptors in IP of skeletal muscle in a rat model of skeletal muscle ischemia. MATERIALS AND METHODS: Groups of 8-15 rats were given the following in vivo treatments: ischemia-reperfusion (I-R: 2.5 h tourniquet-induced ischemia of the right hindlimb, then 2 h reperfusion); IP (three cycles of 5 min ischemia, then 5 min reperfusion) before I-R; cromakalim and I-R; glibenclamide, cromakalim, and I-R; glibenclamide, IP, and I-R; [R]-N(6)-[1-methyl-2-phenylethyl]adenosine (R-PIA) and I-R; adenosine and I-R; and glibenclamide, IP, and I-R. Parameters of muscle function (postischemic maximal force, performance, contraction index, and force after 1 min of stimulation) were then assessed in vitro in the extensor digitorum longus muscle. RESULTS: Pretreatment with either IP or the K(ATP) channel opener cromakalim significantly improved postischemic muscle function. The protective effect of cromakalim was not seen when the K(ATP) channel blocker glibenclamide was added. Glibenclamide, however, did not block IP-induced protection. Pretreatment with the adenosine A(1) receptor agonist 8-(p-sulfophenyl)-theophyllin (8-SPT) or with adenosine did not improve postischemic muscle function. The adenosine receptor agonist did not block IP-induced protection against ischemic damage. CONCLUSIONS: The results show significant improvements in postischemic skeletal muscle function after IP or cromakalim pretreatment but they do not support a role for K(ATP) channels or for adenosine receptors in IP of skeletal muscle.

Animals↗
PubMed2000

[The Advanced Breast Biopsy Instrumentation (ABBI) for evaluation of mammographically suspicious, non-palpable findings of the breast: a reliable diagnosis with minor therapeutic potential].

BACKGROUND: Stereotactic biopsy techniques supersede conventional hook-wire localization followed by open excision to clarify the dignity of nonpalpable mammographic lesions. The advanced breast biopsy instrumentation (ABBI) allows stereotactically guided excision of a specimen up to 20 mm in diameter on an outpatient basis under local anaesthesia. METHODS: Demographic information, mammographic and pathological findings, complications, subsequent interventions and sensitivity as well as efficiency of a series of 144 planned ABBI procedures were documented (largest published single institution series). RESULTS: The ABBI procedure was successfully performed in 93.8% (135/144); accurate diagnosis was made in 99.3% (134/135), sensitivity for malignant lesions was 96.9% (31/32) and morbidity was 1.5%. Consistent with other published series margins of the biopsy cylinder containing a malignant lesion were involved in 83.9% (26/31). CONCLUSIONS: Excisional biopsy using the ABBI system is a reliable diagnostic tool with a low incidence of morbidity. The therapeutic use is of limited potential.

Adult↗
PubMed2000

[Small breast carcinomas--less axillary surgery?].

In view of introducing less invasive or selective axillary procedures for small breast cancers we investigated our own pT1 tumor patients. The incidence of pT1 carcinoma, the nodal involvement of pT1a, b and c, the axillary relapse and the overall survival were analyzed. From 1983 till 1997 185 consecutive patients have been treated for breast cancers with a diameter of < or = 20 mm. The survival data after Kaplan-Meier are based on a cohort of 117 patients with a median follow up of at least seven years. There were seven patients with a pT1a carcinoma, 30 with a pT1b and 148 with pT1c carcinoma. On an average 16 axillary lymph nodes were counted by the pathologists. The axillary involvement clearly depends on the size of the primary tumor: no nodal involvement in patients with pT1a carcinoma, 10% in patients with pT1b carcinoma and 30% in patients with pT1c carcinoma. Not one single axillary relapse was detected after this follow up time. The overall ten years survival for patients with pT1a was 100%, 91% for pT1b, but only 74% for pT1c carcinoma. Screening mammography is expected to detect more small breast cancers in pN0 stage. Risks and benefits of axillary dissection have to be carefully evaluated. Axillary involvement of small breast cancers is rare. Only a minority of patients will benefit from routine axillary lymphadenectomy, while the majority runs the risk of complications. The sentinel lymph node (SLN) procedure offers a selective approach to this dilemma.

Adult↗
PubMed2000

[Significance of endoscopic axillary dissection in invasive breast carcinoma after introduction of the "sentinel lymph node" method].

UNLABELLED: Axillary clearance provides prognostic information, determines adjuvant therapy and reduces axillary recurrences. However significant morbidity may follow axillary dissection. Patients with small tumors (pT1a-c) may benefit from new less invasive (endoscopic lymph node dissection) or more selective (sentinel lymph node biopsy) axillary procedures which recently have been introduced. In this prospective study the axilloscopic approach was evaluated. PATIENTS AND METHODS: 55 clinically node negative patients (mean age: 60 years [30-86]) had endoscopic axillary surgery by one single surgeon (1.1996-6.1998). After axillary liposuction individual lymph nodes (level I + II) were identified and removed under direct vision by means of a laparoscope (successful procedure in 95%; n = 52). Patients were followed every four months according to a institution based follow up protocol. Results of 51 patients (1 refused) were analyzed after a median follow up of 22 (7-37) months by self-evaluation questionnaire, interview and clinical examination (including: range of motion of the shoulder joint, circumferences of the upper extremities). RESULTS: An average of 13.3 (5-25) lymph nodes was endoscopically removed. Patients (n = 16; 31%) had involved nodes with a mean of 3.1 nodes positive per individuum. Seromas necessitated needle aspiration in 8 patients (15%). There were no hematomas and one low grade infection (2%). After a median follow up period of 22 (7-37) months no axillary relapse but one trocar site implantation metastasis (1/55, 2%) was detected and resected. No lymph edema was observed. Early range of motion of the shoulder joint was excellent. CONCLUSION: This technique allows the removal of an adequate number of lymph nodes for staging as well as for regional control. The morbidity is low and the medium-term follow-up results are promising. The atraumatic and very well tolerated endoscopic axillary dissection is being replaced by the selective sentinel lymph node procedure.

Adult↗
PubMed2000

[Validation study of the sentinel lymph node (SLN) method in invasive breast carcinoma. Personal data and review of the literature].

BACKGROUND: Axillary lymph node dissection (ALND) is an integral part in the therapy of breast cancer. Axillary lymph node involvement and tumour size are the most important prognostic factors. Restriction of ALND to level I and II (Berg) reduced high morbidity. The increasing proportion of patients with early breast cancer and negative axillary nodes led to a more selective method to avoid unnecessary ALND. The sentinel lymph node (SLN)--the first draining lymph node of a tumour--represents the status of the axilla. A negative SLN prevents from further completion ALND. PATIENTS AND METHODS: From 9/97 to 1/99 44 patients with invasive breast cancer underwent a prospective trial of lymphatic mapping with isosulfanblue and/or lymphoscintigraphy with 99m technetium-labelled human colloid. During the operation a hand-held gamma probe was used for detection. The SLN was removed selectively and examined by routine histopathology (H&E) and immunohistochemistry (IHC). ALND of level I and II was performed in all patients for correlation. RESULTS: The SLN were identified in 41 of 44 patients (93%). 2.4 SLN per patient were harvested, overall 17.6 axillary lymph nodes. Of the 41 patients, 21 patients had positive, 20 patients negative SLN. In the 20 patients with negative SLN only one patient (5%) had metastatic disease on complete dissection (negative predictive value of 95%). In 17 patients with positive axillary lymph nodes 16 were found to have positive SLN, only one SLN was negative (false negative rate of 5.9%). In two of 41 patients micrometastases were detected by IHC. Lymphoscintigraphy revealed drainage to the axilla and internal mammary nodes in two of 28 cases (7%). SUMMARY: Our validation study proves the reproducibility and reliability of the SLN procedure. A multidisciplinary approach is indispensable. The SLN procedure has the potency for becoming the selection criterion whether to perform an ALND or not. Multiple sections and IHC staining improve the detection rate of metastatic disease. Ongoing long time investigations will determine the impact on overall survival. Our own data are discussed in an extended review of the literature.

Adult↗
PubMed2000

Surgical approach to thyroid nodules and cancer.

Fine needle aspiration cytology is the mainstay of the diagnostic work-up of solitary thyroid nodules. Together with the patient's history and the clinical findings, cytology determines the indication for surgery. The minimal intervention for a suspicious nodule consists of thyroid lobectomy. If a diagnosis of malignancy is established, then we recommend total thyroidectomy for all follicular lesions that are larger than 1.5 cm and for high-risk papillary tumours. Near-total thyroidectomy may be appropriate for low-risk patients with papillary carcinoma in whom it is not intended to use radioactive iodine ablation. Whereas ipsilateral lymphadenectomy of the central (primary) compartment should routinely be performed, modified radical neck dissection is only indicated in evident nodal disease of the lateral (secondary) compartment(s). Patients with incidentally discovered differentiated thyroid carcinomas generally do not require complete thyroidectomy unless the tumours are larger than 1.5 cm in diameter or nodal involvement is present. A detailed description of the surgical technique for thyroidectomy and lymphadenectomy is given and an overview of surgical complications is provided.

Frozen Sections↗
PubMed2000

Assessment of telemedicine in surgical education and patient care.

OBJECTIVE: To analyze the value of teleconferencing for patient care and surgical education by assessing the activity of an international academic network. SUMMARY BACKGROUND DATA: The uses of telemedicine include teleeducation, training, and consulting, and surgical teams are now involved, sharing diagnostic information and opinions without the need for travel. However, the value of telematics in surgery remains to be assessed. METHODS: During a 2-year period, weekly surgical teleconferences were held among six university hospitals in four European countries. To assess the accuracy of telediagnosis for surgical cases, 60 randomly selected cases were analyzed by a panel of surgeons. Participants' opinions were analyzed by questionnaire. RESULTS: Seventy teleconferences (50 lectures and 271 case presentations) were held. Ninety-five of the 114 participants (83.3%) completed the final questionnaire. Eighty-six percent rated the surgical activity as good or excellent, 75.7% rated the scientific level as good or excellent, 55.8% rated the daily clinical activity as good or excellent, and 28.4% rated the manual surgical technique as good or excellent. The target organ was identified in all the cases; the organ structure and pathology were considered well defined in 93.3%, and the fine structure was considered well defined in 58.3%. Diagnosis was accurate in 17 cases (28.3%), probable in 25 (41.7%), possible but uncertain in 16 (26.7%), and not possible in 2 cases (3.3%). Discussion among the remote sites increased the rate of valuable therapeutic advice from 55% of cases before the discussion to 95% after the discussion. Eighty-six percent of the surgeons expressed satisfaction with telematics for medical education and patient care. CONCLUSIONS: Participant satisfaction was high, transmission of clinical documents was accurate, and the opportunity to discuss case documentation and management significantly improved diagnostic potential, resulting in an accuracy rate of up to 95%. Teleeducation and teleconsultation in surgery appear to be beneficial.

Cost-Benefit Analysis↗
PubMed2000

Function of fast- and slow-twitch rat skeletal muscle following ischemia and reperfusion at different intramuscular temperatures.

Fast- (peroneal) and slow-twitch (soleus) skeletal muscles of anesthetized Wistar rats were subjected to 3 h of tourniquet ischemia. The intramuscular temperature of the leg was adjusted to 22, 30 or 35 degrees C (n = 12 per group) during ischemia. After 2 h of reperfusion, the muscles were electrically stimulated in vitro and muscular function was analyzed for maximal force, performance, contractility and fatigue. Contralateral nonischemic muscles served as controls. Three hours of ischemia at 30 degrees C did not reduce the function of the peroneal muscles compared to nonischemic controls. The same ischemic stress significantly reduced the function of the soleus muscles compared to nonischemic controls. The postischemic function of the soleus muscles declined with increasing temperature. The postischemic function of the 35 degrees C group of peroneal muscles was significantly reduced compared to the 22 and the 30 degrees C groups, which did not differ. These results provide evidence that fast-twitch muscles are more resistant to ischemia than slow-twitch muscles. They furthermore show a fiber type-specific dependency of postischemic muscle function on intramuscular temperature during ischemia. Hypothermia-sensitive fast-twitch fibers predominate in the skeletal muscles of the extremities. Mild hypothermia could, therefore, reduce tourniquet ischemia-induced injury after surgery of the extremities.

Animals↗
PubMed2000

Knowledge and acceptance of telemedicine in surgery: a survey.

A questionnaire was sent to the chief surgeons at 141 Swiss hospitals to evaluate their knowledge and acceptance of telemedicine in surgery. The response rate was 69%. Ninety-three per cent of all surgical departments used computer technology, 85% regularly used the Web and 88% had an internal hospital network. ISDN lines were used in 58% of the participants' hospitals. While 35% of respondents had participated at least once in networking, only 8% regularly used telemedicine. The opinion was that access to therapeutic advice (87%) was a better use of telemedicine than was obtaining a primary diagnosis (24%), although the majority accepted the principle of making (91%) and receiving (94%) a remote diagnosis. The survey suggested that surgeons are interested in telemedicine and open to its development, although their experience and knowledge are limited. Therefore, telemedicine in surgery may be advanced by creating surgical networks for teleconsultation and tele-education.

Health Knowledge, Attitudes, Practice↗
PubMed2000

Stem cell plasticity in mammals and transdetermination in Drosophila: common themes?

Stem cells have been identified in a number of mammalian tissues (e.g. bone marrow, muscle, gut, skin, and neural tissues). Until recently, it was generally believed that the differentiation potential of a mammalian somatic stem cell is restricted to one tissue only, as in the case of hematopoietic stem cells differentiating into hematopoietic cells. In this sense, somatic stem cells are limited in their differentiation potential. Several lines of evidence now challenge the idea of unilateral development. New reports show mammalian somatic stem cells can, in the course of regeneration, repopulate heterologous cell systems and therefore possess a surprisingly broad spectrum of differentiation potential. Thus, mammalian stem cells are apparently capable of fate changes between stem cell systems, although the mechanisms leading to such changes are unclear. Mechanistic models for fate changes have been proposed in Drosophila, specifically for transdetermination of imaginal discs. Imaginal discs of the larva are the primordia of the adult exoskeleton and appendages, for example, legs, and antennae. Transplantation experiments of imaginal discs have shown that discs are determined for their disc identity. Transdetermination in Drosophila refers to cases when, after regenerative cell divisions, imaginal disc cells change from one state of determination to another, initiating a pathway of differentiation leading to structures other than those corresponding to the initial state or determination; for example, an antennal imaginal disc transdetermines to a leg imaginal disc. A fate change is thus possible in both mammalian somatic stem cells and Drosophila imaginal discs following transplantation and subsequent proliferation. Here we summarize and compare observations made in such cases of stem cell and imaginal disc differentiation.

Animals↗
PubMed1999

Reversible cerebral ischemia in patients with pheochromocytoma.

Cerebral ischemia and symptoms of stroke can occur as a rare manifestation in patients with pheochromocytoma. We describe a 45-year-old woman who was admitted because of a right-sided hemiparesis due to an ischemic lesion in the left hypothalamus. The clinical diagnosis of a pheochromocytoma was proven by highly elevated urinary catecholamines and confirmed histologically after operation. The successful removal of the tumor led to the almost complete recovery of the neurological deficiencies. It is of vital importance to know this atypical presentation of pheochromocytoma. The diagnosis of pheochromocytoma should be suspected in patients with focal cerebral symptoms, particularly in the presence of intermittent hypertension or other paroxysmal symptoms suggestive of pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1999

[Cecum reservoir].

UNLABELLED: The choice of the best reconstruction technique following resection of either the stomach or the rectum remains a matter of discussion. While there is no problem in reconnecting intestinal segments, which do not serve as a reservoir, there are many different operation techniques to replace the stomach and rectum, producing significantly different functional results. The ileocecal segment offers an excellent intestinal reservoir combined with an antireflux mechanism, thus presenting an ideal replacement for the stomach. For replacement of the rectal reservoir as well, the ileocecal segment may be used in the first line of treatment. METHOD: The ileocecal segment was used in 20 patients following gastric resection and lymphadenectomy to reconstruct the intestinal passage between the esophagus and the duodenal stump (group A). In some further 44 patients (group B) the ileocecal segment was used to replace the rectum between the descending colon and the dentate line following resection for very low-grade rectal cancer. Mortality and morbidity were investigated in both groups. In group A quality of life, weight loss, dumping and reflux symptoms were evaluated. In group B continence, discrimination, defecation quality, urge and the patient satisfaction were investigated. All data were recorded prospectively. RESULTS: Early and late mortality were not different compared to other reconstruction types. In each group one patient died within 60 days postoperatively due to myocardial infarction. The morbidity following stomach replacement was 20%, following rectal replacement 4.6% during hospitalization and 13.8% during follow-up, respectively. One patient complained about heartburn, but endoscopically no pathology was detected in any patient. Three months postoperatively the patients' weight remained stable or started to increase. Three months following rectal replacement 87% of the patients were continent with further improvement over 2 years. Soiling mainly during the night remained over 2 years in 44%. 88% of the patients were completely satisfied 2 years postoperatively. CONCLUSION: The replacement of either the stomach or the rectum using the ileocecal segment with an adequate surgical technique is safe and produces excellent functional outcome regarding the reconstruction of the intestinal passage as well as the reservoir function of the primary organ. Furthermore, preservation of the duodenal passage after gastrectomy may prevent dysregulation of the endocrine and exocrine pancreatic hormones.

Anastomosis, Surgical↗
PubMed1999

[Malignant pheochromocytoma in the 17th week of gestation].

INTRODUCTION: Pheochromocytoma during pregnancy is rare and represents a high risk for mother and fetus. Due to the variable clinical presentation it may be mistaken for preeclampsia. CASE: A 34-year-old primipara with hypertension up to 240/120 mmHg. After diagnosis of a pheochromocytoma its resection together with lymph node metastasis in the 17th week of gestation was performed. CONCLUSION: The definitive diagnosis is confirmed by elevation of serum catecholamines and their metabolites in a 24-h urine collection. Localization during pregnancy can be made by ultrasound and MRI. The definitive treatment is surgical removal after administration of adrenergic blockers. If discovered later in pregnancy, delivery by elective caesarean section followed by tumor resection is recommended. Since about 10 % of pheochromocytomas are malignant, postpartum screening is required to detect and treat extraadrenal or metastatic tumors by MIBG scintigraphy, chemotherapy or surgical procedures.

Adrenal Gland Neoplasms↗
PubMed1999

[Telematic and surgery: methods, terminology and instructions].

BACKGROUND: Telematic is the application of computer technology in modern telecommunication. Telemedicine will be of growing importance in the international collaboration in surgery. OBJECTIVE: Review of the different telematic applications for surgery and presentation of technology and tools. Practical user's guide. METHOD: Analysis of our international network of telesurgical staff meetings between 6 University Hospitals. Review of the situation of telemedicine in Switzerland and around the world. RESULTS: After performing some comparative tests we chose to work with 6 ISDN channels at the world wide standard H.320 (rate of 384 Kb/s) which is widely available in Switzerland and around the world. Technical options, market opportunities and relationship between needs and goals of telemedicine are presented on a user point of view. DISCUSSION: More than 70 telesurgical staff meetings allowed us to get an overview of this technology, in order to benefit of telemedicine applications for teaching and clinical use. Important factors are the analysis of needs and goals prior to the teleconference. CONCLUSION: Consultation, second opinion, teaching and training should be new clinical applications of telemedicine, leading to an increase of surgical quality control in Europe and in the world.

Computer Communication Networks↗