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Biomedical subjects

S Widmer

Publications and source records attributed to S Widmer.

At least 19 recordsLinked to original sources
PubMed2006

Presumed macular toxicity of intravitreal antibiotics.

BACKGROUND: Intravitreal injection is the most effective route for administration of antibiotics in intraocular infections. PATIENTS AND METHODS: Two patients presented with a metal foreign body in the central vitreous without damage to the retina. RESULTS: Foreign bodies were removed with an intraocular magnet and limited vitrectomy was performed. Because of leukocytic infiltration of the vitreous, 1 mg vancomycin and 0.4 mg amikacin were injected in the vitreous at the end of the surgery. Postoperative visual acuity did not reach preoperative values in both patients. ERG examination revealed reduced photoreceptor activity. We speculate that amikacin may have reached the macula in a high and toxic concentration in an incompletely vitrectomized eye. CONCLUSION: The currently accepted intravitreal use of amikacin may cause retinal toxicity.

Amikacin↗
PubMed2005

Lethal Epstein-Barr virus associated NK/T-cell lymphoma with primary manifestation in the conjunctiva.

BACKGROUND: Lethal midline granulomas (LMG) are very rare angiocentric NK/T-cell lymphomas in association with Epstein-Barr virus. LMG are reported mainly in East Asia occurring in immune compromised patients. HISTORY AND SIGNS: A 41-year old male patient presented with a conjunctival swelling of his upper left eyelid. The lesion had increased over a period of 2 months despite topical corticosteroid treatment. Conjunctival biopsy revealed a highly malignant, CD3 + and BCL2 + extranodal T-cell lymphoma with features of an NK/T-cell origin (CD56 +, TIA + TCR-rearrangement: germline). All lymphoma cells were positive for Epstein-Barr virus RNA. The proliferation rate was highly elevated at 100 %. THERAPY AND OUTCOME: Systemic 1 (st) cycle chemotherapy with cyclophosphamide, doxorubicin, vincristin and prednisone resulted in a complete remission of the swelling within 4 days. However, one week later a massive conjunctival tumour reappeared with only partial regression after combined chemo- and radiotherapy. The patient died within a month because of untreatable pancytopenia due to malignant bone marrow infiltration. CONCLUSIONS: LMG is a rare but highly malignant Epstein-Barr virus associated NK/T-cell lymphoma that can occur in healthy, immune competent Caucasians. This is the first reported case of an LMG in an immune-competent Caucasian patient with primary ocular manifestation. The LMG has a high mortality rate despite systemic treatment and can be lethal within a few months or even weeks.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[Comparison and reproducibility of 3 indirect methods for measuring blood pressure].

It is rare to find systematic comparisons of various methods for measuring blood pressure. This study aimed to compare blood pressure measurements performed by the doctor, by the patient and on a 24-hour basis with regard to their reliability and reproducibility. A total of 84 patients were included in the study. All patients had their blood pressure measured at the doctor's office twice on day 1 and 10, by themselves and with a 24-h blood pressure measuring unit. The doctors obtained the highest means. The mean systolic and diastolic value taken on the day 1 was higher by 13 mmHg and 8 mmHg than the ABPM value or the measurement obtained by the patient at home, respectively. This difference was still present at the end of the study (7 mmHg and 5 mmHg compared to ABPM and 9 mmHg and 6 mmHg compared to the patient's measurements, respectively). The values obtained by 24-h measurement and the patients themselves showed a better reproducibility than the doctor's measurements. Both methods are thus suitably good for use in diagnostics and therapy monitoring. Compared to the patient's own measurements, the 24-hour blood pressure measurement is less dependent on the patient's reliability.

Adult↗
PubMed2001

Real-time pachymetry during photorefractive keratectomy using optical low-coherence reflectometry.

Optical low-coherence reflectometry (OLCR) was used as a noncontact method to measure the central corneal thickness of three patients intraoperatively during photorefractive keratectomy. Continuous on-line measurements were performed on the intact cornea immediately before the beginning of surgery, after the removal of the corneal epithelium, during laser tissue photoablation, and for 3 min after the ablation process. Corneal thinning due to evaporation was studied on a separate patient with the OLCR instrument, and it was found to be -0.14 microm/s during the first 5 min after epithelium removal. This baseline corneal thinning rate was used as a fit parameter to calculate actual from measured ablation depths. The measurements showed a maximum difference of +/-10 microm between planned ablations (34-92 microm) and measured ablation depths.

Adult↗
PubMed1996

Scavenging anesthetic gas from a membrane oxygenator during cardiopulmonary bypass.

Concerns remain about the acute and chronic effects on personnel of waste anesthetic gases in the operating room environment. This study demonstrates a simple and effective means of scavenging waste anesthetic gases when halogenated anesthetics are administered through the pump oxygenator during cardiopulmonary bypass. This technique safeguards workers' health by reducing ambient anesthetic levels below the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limits.

Air Pollutants, Occupational↗
PubMed1995

Cross-reactivity of rocuronium with other neuromuscular blocking agents.

The cross-reactivity of rocuronium with other neuromuscular blocking agents (NMBAs) was studied in 31 patients known to be allergic to a muscle relaxant. Tests for diagnosing cross-reactivity were skin tests (prick tests and intradermal tests: IDTs), detection by RAST assay of IgEs against the quaternary ammonium group (QAS-RIA: quaternary ammonium sepharose radio-immuno-assay), QAS-RIA inhibition test to detect IgE specificity, and leucocyte histamine release test (LHRT). Skin tests were performed with rocuronium, suxamethonium, gallamine, vecuronium, pancuronium, atracurium. The threshold for cross-reactivity was 10(-1) with all the NMBAs except for atracurium (10(-2)). The inhibition test and LHRT were performed with rocuronium and the NMBA responsible for the shock. Ten volunteers made up the control group for prick tests, QAS-RIA, LHRT. Cross-reactivity was found in 30 patients out of 31. Rocuronium did not cross-react in 10 patients out of 31. They had negative cutaneous tests and negative LHRTs. In one of the five patients allergic to all the NMBAs available, rocuronium was the only one which did not cross-react. In those 10 patients, rocuronium may be safely used for subsequent anaesthesia. In terms of allergy, rocuronium appeared to be very close to the other steroidal NMBAs.

Adult↗
PubMed1994

Use of a scapular free flap for reconstruction of the cricoid cartilage in pharyngolaryngeal oncology.

A newly developed technique for cricoid reconstructive surgery is presented and discussed. This method allows us to increase the number of patients presenting with squamous cell carcinoma who may benefit from partial laryngectomy. The method is based on the transfer of a vascularized scapular flap to reconstruct half a resected cricoid. Two alternatives may be used whether anterior laryngectomy preserves the half posterior cricoid and both arytenoids or a hemilateral laryngectomy leaves one arytenoid and half the cricoid. Complementary radiotherapy may be performed after surgery. Satisfactory results are reported from an initial series of three patients.

Analgesia↗
PubMed1993

Prospective study of risk factors in natural rubber latex hypersensitivity.

Five hundred sixty-nine subjects routinely underwent skin prick tests for latent sensitization to latex. The study of risk factors included skin tests to inhalant allergens, to diagnose atopy, and a questionnaire aimed at revealing frequent exposure to latex such as the wearing of gloves, multiple surgical procedures, or urinary catheterization. The subjects were categorized into five groups: group I, subjects with no risk factor (n = 272); group II, nonatopic subjects exposed to latex (n = 73); group III, atopic subjects not exposed (n = 180); group IV, exposed atopic subjects (n = 44); and group V, subjects with a history of intraoperative anaphylactic shock caused by latex (n = 13). Twenty-five subjects had spina bifida and were in either group II (14 subjects) or group IV (11 subjects). The questionnaire identified a probable allergy to latex in 18 subjects: 16 cases were confirmed by skin test, but responses were not informative in 23 patients who were sensitive to latex. Positive prick tests to latex were obtained in 0.37% of group I, 6.85% of group II, 9.44% of group III, and 36.36% of group IV. Of the children with spina bifida, 32% had positive skin test results. As risk factors, atopy and exposure were synergistic. We recommend predictive prick tests not only in children with spina bifida but also in any atopic subject or in any patient with a history of frequent exposure to latex. Latex could be considered a habitual allergen. The use of latex urinary catheters should be avoided in patients who are catheterized on a daily basis.

Adolescent↗
PubMed1993

[An original technique of reconstruction of the cricoid cartilage by vitalized scapular flap. Application to pharyngolaryngeal carcinology].

A personal technique for cricoid reconstructive surgery is presented and discussed. A transfert of a free living scapular flap by microvascular anastomoses is used for reconstructing half cricoid resection. We can with this technique increase the number of partial laryngectomy in patients with squamous cell carcinoma. Two techniques are possible: The half anterior laryngectomy conserves only the half posterior cricoid and the twice arytenoids. The half lateral laryngectomy conserves one arytenoid and a half cricoid.

Cricoid Cartilage↗
PubMed1990

[Anesthetics responsible for anaphylactic shock. A French multicenter study].

Combined allergological and anaesthetic consultations have been started in the last few years in eight French Teaching Hospitals so as to explore peranaesthetic anaphylactoid shocks. A survey was carried out in these centers in order to collect patients investigated with the same protocol, for the assessment of the incidence of anaphylaxis in France, as well as the involved drugs. Investigations were always carried out at least 6 to 8 weeks after the accident. The tests used to diagnose IgE-dependent anaphylaxis were skin tests (prick and intradermal tests, carried out in all eight centers), the radioimmunological assay of specific anti-quaternary ammonium IgE, together with an inhibition test with thiopentone and propofol (six centers), leukocyte histamine release (five centers) and human basophil degranulation tests (three centers) for those drugs for which no specific antibody assay exists. The collected data involved 1,240 patients, investigated within the last four years. Anaphylaxis was diagnosed in 821 patients (66.2%). Muscle relaxants were responsible in 668 cases (80% of cases of anaphylaxis). Suxamethonium was the main cause (54.3% of shocks due to muscle relaxants), followed by vecuronium (15.3%). General anaesthetics (hypnotics and benzodiazepines) were responsible for 9.2% of all cases of anaphylaxis opioids for 2.6%. There were only three cases of shock due to local anaesthetic agents. Latex and ethylene oxide are becoming increasingly involved. It would therefore seem mandatory to carry out after any anaphylactoid accident an assessment with sensitive and specific tests for anaphylaxis. Diagnosing anaphylaxis means that the involved drug should be used never again in that patient. Because muscle relaxants are by far the most involved drugs, anaesthetists should use them only when really required.

Analgesics, Opioid↗
PubMed1990

Simultaneous anaphylaxis to thiopentone and a neuromuscular blocker: a study of two cases.

Two women experienced anaphylactoid reactions after induction of general anaesthesia. Prick tests, intradermal tests (IDT), human basophil degranulation tests (HBDT) and a quaternary ammonium sepharose radioimmunoassay were undertaken several weeks later and repeated together with a leucocyte histamine release (LHR) test after 4 months. Anaphylaxis to suxamethonium was documented by four tests in patient 1 and to pancuronium by four tests in patient 2. Anaphylaxis to thiopentone was shown with IDT, HBDT and LHR in both women. It was concluded that simultaneous anaphylaxis to thiopentone and a neuromuscular blocker had occurred in these patients.

Adult↗
PubMed1988

[Leukocyte histamine liberation tests for the diagnosis of anaphylactic reaction to curare-like agents].

Anaphylaxis to myorelaxants is the main etiology of adverse reactions to anesthetics and adjuvants. The diagnosis relies on skin tests--prick or intradermal tests--radio-immunoassays for series specific IgE, human basophil degranulation tests and leucocyte histamine++ release. 28 patients with an anaphylaxis to myorelaxants have been studied, using the two tests. Skin tests are the more specific and accurate ones. ARIA using a quaternary ammonium hydrated gel, is highly specific and its sensitivity reaches 80%. The leucocyte histamine release may be interest in evaluating anaphylaxis especially when another drug might be involved. The sensitivity of HBDT is low, indicating that HBDT is to be discarded as far as other tests have been developed, for myorelaxants. However, its usefulness for other drugs has to be compared to leucocyte histamine release.

Anaphylaxis↗
PubMed1988

[The amount of histamine released in vivo by hypnotics (thiopental, methohexital, propofol) studied by assays of plasma histamine].

Accidents observed during induction of anaesthesia are most often linked to non-specific histamine liberation. The sale of new hypnotics (Methohexital and Propofol), has brought the hope that their histamine-liberation potential would be lower. The study was done in patients who were at risk of histamine-liberation (atopics, drug allergies etc.). Two series of patients were studied after anti H1 and tranquilizer premedication. Histamine liberation by Propofol versus Thiopental as the inducer was studied in the first group. In the second, the combination was Methohexital versus Thiopental. In both series studied the new hypnotics Propofol and Methohexital did not release histamine non-specifically in atopics at risk. Neither clinical reactions non increase of histamineamia were seen. It is concluded that these two new drugs are safe.

Drug Hypersensitivity↗
PubMed1987

[The value of prick tests in the detection of anaphylaxis caused by muscle relaxants].

Intradermal tests (IDR) are a sure diagnostic procedure for confirming the IgE origin of anaphylactoid accidents due to muscle relaxant drugs. Because carrying these out and interpreting them correctly is difficult, epidermal prick-tests (PT) could be used if they proved as sure as IDR. To ascertain this, IDR and PT were carried out in 38 patients who had a shock after being given a muscle relaxant 6 months to 5 years previously; for these tests, increasing concentrations of five muscle relaxants were used (suxamethonium, gallamine, alcuronium, pancuronium and vecuronium). The PT were also carried out with the five same pure and diluted muscle relaxants in a group of 147 volunteer controls. For the 38 patients, PT and IDR were always positive for the same drugs, but at different concentrations, the epiderm seeming less sensitive than the derm (with a ratio of 1 to 100). In the control group, all the tests were negative, even with the pure drug. PT with muscle relaxants were sensitive, specific of anaphylaxis, and permanent. Easy to carry out, easily interpreted, they could be useful as tests for predicting latent sensitisation in risk patients requiring muscle relaxants. But all muscle relaxants must be tested, and not just the one the anaesthetist is likely to use.

Adolescent↗