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Biomedical subjects

K Johansen

Publications and source records attributed to K Johansen.

At least 19 recordsLinked to original sources
PubMed1999

Incidence and estimates of the disease burden of rotavirus in Sweden.

Laboratory and hospitalization data from two children's hospitals with large primary catchment areas and national laboratory and hospitalization data for children under 4 y of age with acute diarrhoea were compiled to estimate the number of hospitalizations and the cost burden associated with rotavirus diarrhoea in Sweden. According to our estimates 1500-1700 rotavirus-associated hospitalizations occur annually in Sweden in children under 4 y of age (3.7 hospitalizations/1000 children/y). This number represents 2.3% of admissions for all diagnoses in children of this age group. The cost of these hospitalizations is 13.5-15 million Swedish crowns (US$1.8-2 million). Serotyping by PCR for two years revealed that serotype 1 (G1) was the most common (49% and 58%, respectively) identified. Serotypes 2-4 were identified in the following proportions G2 (23% and 5%), G3 (21% and 0%) and G4 (7% and 16%). The national laboratory report data for 1993-96 show that as much as 7-13% of rotavirus infections occur in elderly people.

Age Distribution↗
PubMed1999

Viral diarrhea in children in Beijing, China.

A study was undertaken from November 1994 to August 1996 to determine the role of viruses in children (< or =5 years of age) hospitalized at Beijing Children Hospital, Beijing China, for acute diarrhea. Stool samples from diarrheal patients were investigated by ELISA, electron microscopy, and RT-PCR for the presence of rotavirus, calicivirus, astrovirus, and adenovirus. Group A rotavirus was detected in 55.9% of all diarrheal patients and comprised 82.5% of all viruses detected. Group A rotavirus samples were further characterized for their G-type specificity by RT-PCR. Four major G types (1-4) were identified. G1 to G4 accounted for 58.9%, 15.7%, 16.8%, and 6.3%, respectively, of the serotyped samples. Almost all rotavirus infections occurred in children less than 1 year of age, with a significant clustering during the winter months. Group C rotavirus was detected in one 18-month-old child. Astroviruses, caliciviruses, and adenoviruses were detected in 8.5%, 7.6%, and 2.5% of the hospitalized children, respectively. This, the first viral etiological study of childhood diarrhea in China, concludes that rotavirus G1-4 strains play an important role in severe diarrhea in Beijing children.

Adenoviridae↗
PubMed1998

Automated on-line dialysis for sample preparation and HPLC analysis of antidepressant drugs in human plasma. Inhibition of interaction with the dialysis membrane.

Antidepressant drugs interact with the dialysis membrane and were selected as model substances to study inhibition of analyte-membrane interactions. A chemometric approach based on response surface modelling was used for screening and optimisation of dialysis recoveries. Optimal dialysis recoveries (52-65%) were obtained for the model compounds (mianserine, amitriptyline, nortriptyline, imipramine and desimipramine) when a cationic surfactant added to the donor solution of the dialyser was used to inhibit analyte-membrane interactions. Automated analysis of antidepressants in plasma was performed by connecting the ASTED (Automated Sequential Trace Enrichment of Dialysates) system to high-performance liquid chromatography (HPLC). The drugs were detected by ultraviolet detection and fluorescence detection after post-column photochemical reaction. Validation of the method showed linear standard curves for all the drugs in the concentration range 50-2000 nmol 1-1. Within-and between day relative standard deviations ranged from 1.1 to 5.7%.

Antidepressive Agents↗
PubMed1998

Antirotavirus immunoglobulin A neutralizes virus in vitro after transcytosis through epithelial cells and protects infant mice from diarrhea.

Rotaviruses are the major cause of severe diarrhea in infants and young children worldwide. Due to their restricted site of replication, i.e., mature enterocytes, local intestinal antibodies have been proposed to play a major role in protective immunity. Whether secretory immunoglobulin A (IgA) antibodies alone can provide protection against rotavirus diarrhea has not been fully established. To address this question, a library of IgA monoclonal antibodies (MAbs) previously developed against different proteins of rhesus rotavirus was used. A murine hybridoma "backpack tumor" model was established to examine if a single MAb secreted onto mucosal surfaces via the normal epithelial transport pathway was capable of protecting mice against diarrhea upon oral challenge with rotavirus. Of several IgA and IgG MAbs directed against VP8 and VP6 of rotavirus, only IgA VP8 MAbs (four of four) were found to protect newborn mice from diarrhea. An IgG MAb recognizing the same epitope as one of the IgA MAbs tested failed to protect mice from diarrhea. We also investigated if antibodies could be transcytosed in a biologically active form from the basolateral domain to the apical domain through filter-grown Madin-Darby canine kidney (MDCK) cells expressing the polymeric immunoglobulin receptor. Only IgA antibodies with VP8 specificity (four of four) neutralized apically administered virus. The results support the hypothesis that secretory IgA antibodies play a major role in preventing rotavirus diarrhea. Furthermore, the results show that the in vivo and in vitro methods described are useful tools for exploring the mechanisms of viral mucosal immunity.

Animals↗
PubMed1998

Portal decompression using the inferior mesenteric vein.

We report five patients with variceal hemorrhage, in three cases secondary to diffuse thrombosis of the portal, superior mesenteric and splenic veins. Mesenteric angiography demonstrated patency of the inferior mesenteric vein (IMV) in each, and successful portal decompression by anastomosis of the IMV to the left renal vein (n = 4) or the inferior vena cava (n = 1) was accomplished. Bleeding was permanently controlled: four patients have survived from one to eight years post-operatively. Because shunt procedures utilizing the IMV are technically straightforward, subtotally decompress the portal system and avoid the right upper quadrant, they may be advantageous in certain clinical settings.

Adult↗
PubMed1998

Compartment syndrome: new insights.

Long recognized as a potential problem in trauma patients or victims of acute extremity ischemia, compartment syndrome is seen in other patient populations as well. In such patients, the absence of timely diagnosis and effective treatment inevitably results in loss of extremity neuromuscular function. New insights into the pathophysiology of compartment syndrome provide opportunities for earlier and more accurate recognition as well as the possibility that the morbid consequences of the syndrome might be mitigated or in certain settings even prevented.

Compartment Syndromes↗
PubMed1997

Automated on-line dialysis, trace enrichment and high-performance liquid chromatography. Inhibition of interaction with the dialysis membrane and disruption of protein binding in the determination of clozapine in human plasma.

Problems related to interaction of drugs with the dialysis membrane and to protein binding must be overcome in order to develop automated methods for drug analysis based on on-line dialysis, trace enrichment and HPLC. In order to study these problems, clozapine and its active metabolite N-desmethylclozapine were chosen as model compounds because they were found to interact with the dialysis membrane, and clozapine is highly protein bound. Addition of a cationic surfactant, dodecylethyldimethyl ammonium bromide, to the donor solution and to the plasma samples was found to inhibit interaction of the drugs with surfaces. The protein binding in plasma was disrupted prior to dialysis by lowering the pH with hydrochloric acid and the plasma proteins were solubilised with glycerol. The results obtained were used to develop a fully automated method for the determination of clozapine and N-desmethylclozapine in human plasma. More than 100 samples could be analysed within 24 h. The limit of detection in human plasma was 0.050 mumol/l for clozapine and 0.055 mumol/l for N-desmethylclozapine. Linearity was found for drug concentrations between 0.25-3 mumol/l. The relative standard deviations were between 1.2-6.7% and the method was applicable for therapeutic drug monitoring.

Antipsychotic Agents↗
PubMed1997

Sartorius myoplasty for infected vascular grafts in the groin. Safe, durable, and effective.

OBJECTIVE: To review the safety, durability, and efficacy of sartorius myoplasty in the treatment of localized vascular prosthetic graft infection in the groin. DESIGN: Case series. SETTING: University teaching hospitals. PATIENTS: Fourteen patients with 15 exposed, eroded, or overtly infected prosthetic vascular grafts in the groin, treated during 7 years. INTERVENTIONS: Groin exploration for delineation of the extent of vascular graft infection, followed by extensive perigraft debridement, then dissection and rotation of the ipsilateral sartorius muscle to cover the involved graft. MAIN OUTCOME MEASURES: Healing of groin wound with preservation of vascular graft function, limb salvage, length of hospital stay, impact of specific wound bacteria, and evidence of long-term hip dysfunction. RESULTS: During a mean hospital stay of 8.7 days, sartorius myoplasty was accomplished with 20% morbidity. Hip flexor function was initially impaired in all 14 patients, but functional deficit was negligible at late assessment. During mean follow-up of 36 months, all wounds were healed, and all limbs were salvaged. Two late deaths occurred, and 2 limbs were ultimately amputated due to progressive loss of vascular outflow. CONCLUSION: Sartorius myoplasty is a simple, safe, durable, and effective technique for preservation of locally infected or exposed vascular grafts in the groin.

Adult↗
PubMed1997

Morbid prognostic features in patients with chronic liver failure undergoing nonhepatic surgery.

BACKGROUND: Although the risk of portal decompression surgery is accurately predicted by objective scoring systems (Child classification and Pugh score), few useful prognostic criteria exist regarding nonhepatic surgery in patients with chronic liver failure. OBJECTIVE: To evaluate the clinical findings associated with perioperative mortality in patients with chronic liver failure undergoing nonhepatic surgery. DESIGN: A retrospective cohort study. SETTING: University teaching hospitals. PATIENTS: Forty consecutive patients with an International Classification of Diseases, Ninth Revision (ICD-9), diagnosis of chronic liver failure and one or more of the following: jaundice, cirrhosis, chronic hepatitis, or alcoholism. INTERVENTIONS: Forty operations, including 28 abdominal procedures, 2 coronary artery bypass grafts, 5 orthopedic procedures, and 5 miscellaneous procedures. MAIN OUTCOME MEASURES: Thirty-day mortality as related to 19 preoperative clinical and laboratory variables. RESULTS: Eleven (28%) of the patients died within 30 days of surgery. By univariate analysis, the following variables were significantly (P < .05, pearson chi 2 test for categorical data or Mann-Whitney U test for continuous data) associated with nonsurvival: encephalopathy, congestive heart failure, the need for emergent surgery, infection, hyperbilirubinemia, international normalized ratio greater than 1.6, hypoalbuminemia, and an elevated creatinine level. By multiple logistic regression analysis, an international normalized ratio greater than 1.6 and encephalopathy were associated with a greater than 10- and 35-fold increased mortality risk, respectively. Child classification and Pugh score failed to predict 30-day mortality. CONCLUSIONS: We identified 8 clinical and laboratory variables associated with death within 30 days in patients with chronic liver failure undergoing nonhepatic surgery. Two factors-international normalized ratio greater than 1.6 and encephalopathy-independently predicted mortality by multivariate analysis. Neither Child classification nor Pugh score was prognostically helpful. Nonhepatic surgery confers a substantial mortality risk in patients with chronic liver failure.

Adult↗
PubMed1997

Neutralization of rotavirus and recognition of immunologically important epitopes on VP4 and VP7 by human IgA.

Rotavirus is an important cause of gastroenteritis in young children. Locally produced antibodies in the intestinal mucosa are proposed to play an important role in the defence against rotavirus infection, but it is not established whether IgA alone can neutralize rotavirus, nor if IgA antibodies recognize epitopes involved in protective immunity. To evaluate whether human IgA plays a role in virus neutralization, serum IgA was purified from nineteen rotavirus seropositive individuals and examined for its neutralizing capacity by a peroxidase focus reduction test. In all nineteen sera IgA neutralizing antibodies against serotype 3 (rhesus rotavirus) were demonstrated. Purified IgA was further investigated and shown not only to neutralize rotavirus in solution but also to neutralize rotavirus already pre-bound to epithelial cells (MA-104). IgA epitope blocking assays with monoclonal antibodies directed against heterotypic epitopes on VP4 and VP7, revealed that IgA antibodies from 4/16 sera recognized epitopes on VP4, while 5/16 sera recognized a VP7 epitope. When whole sera were investigated for comparison 7 and 9/16 sera recognized epitopes on VP4 and VP7 respectively.

Adult↗
PubMed1997

Ruptured Salmonella mycotic aneurysm of the extracranial carotid artery.

Mycotic aneurysms of the extracranial carotid artery are rare and difficult to diagnose and can lead to significant medical morbidity. Treatment of these lesions requires expert surgical management and necessitates an assiduous search for an underlying source. We report a case of a ruptured mycotic aneurysm of the cervical carotid artery due to Salmonella infection successfully treated by wide excision and saphenous vein patch angioplasty.

Aged↗
PubMed1997

Delayed abdominal closure in the management of ruptured abdominal aortic aneurysms.

BACKGROUND: Resuscitative measures associated with ruptured abdominal aortic aneurysm (rAAA) repair may result in massive edema of the bowel, retroperitoneum and abdominal wall. The resulting "abdominal compartment syndrome" may compromise abdominal closure and may be associated with respiratory, renal and cardiovascular deterioration. METHODS: The medical records of 23 patients surviving initial operative repair of a rAAA were retrospectively reviewed. Eight underwent delayed abdominal closure after early approximation with silastic sheets (n = 6) or of the skin only (n = 2). Ultimate outcome, as well as several pulmonary and cardiovascular parameters, were compared with patients undergoing standard primary fascial closure (n = 15). RESULTS: A trend toward improved survival was apparent in the group undergoing delayed abdominal wall closure. Significant improvements in oxygenation and mixed venous oxygen saturation were observed in these patients, and there were fewer late deaths due to multiple organ failure. No patient undergoing delayed abdominal closure developed a graft infection. CONCLUSIONS; As in massively resuscitated trauma victims, delayed laparotomy closure in rAAA patients may confer a physiologic and survival benefit.

Aged↗
PubMed1996

Left-upper-quadrant devascularization for 'unshuntable' portal hypertension.

BACKGROUND: No simple solution exists for the patient with bleeding due to diffuse splanchnic venous thrombosis (so-called unshuntable portal hypertension). Radical gastroesophageal devascularization or extended esophagogastrectomy has been considered obligatory in this setting. OBJECTIVE: To examine the use of 1-stage, left-upper-quadrant devascularization for unshuntable portal hypertension. DESIGN: A retrospective call-back survey. SETTING: A regional referral center. PATIENTS: Eight consecutive patients with recurrent bleeding from esophagogastric varices due to diffuse splanchnic venous thrombosis. INTERVENTIONS: Splenectomy, staple transection of the esophagus, and proximal gastric devascularization. MAIN OUTCOME MEASURES: Operative complications, recurrent bleeding, survival, and quality of life. RESULTS: No operative deaths occurred, and 7 of 8 patients who were treated for unshuntable portal hypertension and who were followed-up for 1 to 15 years (mean, 4.7 years) are alive. No patient has had a recurrent variceal hemorrhage. A second endoscopy has demonstrated small varices in 4 patients. Early and late complications occurred in 3 and 1 of the patients, respectively. CONCLUSIONS: Left-upper-quadrant devascularization is a technically straightforward, safe, effective, and durable alternative to the Sugiura procedure or to radical esophagogastrectomy in patients with unshuntable portal hypertension.

Adult↗
PubMed1996

Pelvic revascularization by direct hypogastric artery reconstruction.

BACKGROUND: While pelvic arterial insufficiency, either acute or chronic, results in stereotypic clinical findings which may readily be reversed by indirect techniques of revascularization, few reports document the indications for, techniques of, and results following direct pelvic revascularization by reconstruction of the hypogastric artery. METHODS: Retrospective review of 8 patients with symptomatic pelvic arterial insufficiency undergoing direct hypogastric artery reconstruction during the period from 1984 to 1995. RESULTS: Eight patients underwent unilateral hypogastric artery reconstruction by bypass graft (3 patients) or endarterectomy and patch angioplasty (5 patients). One patient had immediate symptomatic relief of his symptoms, but was lost to follow-up after 1 month. One patient manifested no symptomatic improvement despite a technically successful operation. The remaining 6 patients experienced significant symptomatic relief that has persisted during follow-up from 3 months to 11 years postoperatively. Among 4 men in whom erectile impotence comprised one of the indications for intervention, 3 reported sustained restoration of sexual function. CONCLUSION: In properly selected patients, direct pelvic revascularization by hypogastric artery reconstruction may predictably and durably relieve symptoms of pelvic arterial insufficiency.

Adult↗
PubMed1996

Passive immunity against diarrhoea.

Passive immunity against a variety of respiratory and gastrointestinal pathogens has recently been increasingly used clinically, and oral administration of antibodies of both human and non-human origin has been tried both for prophylaxis and treatment of infections. Although the former type of therapy has been shown to be effective, data on the latter are still scarce. This commentary focuses on recent studies on successful oral therapeutic administration of bovine immunoglobulins.

Animals↗
PubMed1995

Solid-phase microextraction for the determination of the free concentration of valproic acid in human plasma by capillary gas chromatography.

The potential of solid-phase microextraction in the bioanalysis of drugs is demonstrated. The free concentration of valproic acid in human plasma was determined by equilibrium dialysis at room temperature. To the dialysate was added an internal standard and the pH was adjusted to 2.5. The polymethylsiloxane-coated fused-silica fibre of the solid-phase microextraction device was inserted into the dialysate for 3 min. The sorbed analytes were then thermally desorbed at 210 degrees C in the split-splitless injection port of the gas chromatograph, separated on a Nukol capillary column and detected with a flame ionization detector. The method was shown to be highly reproducible with a detection limit of 1 microgram/ml of free valproic acid in human plasma.

Chromatography↗