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Biomedical subjects

B Aberg

Publications and source records attributed to B Aberg.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparison of vascular effects of ropivacaine and lidocaine on isolated rings of human arteries.

Ropivacaine is a new local anaesthetic agent. Previous animal studies have indicated that vasoconstrictor effects are elicited by ropivacaine in vitro and subcutaneously and that it produces blanching of the skin if injected subcutaneously in humans. Lidocaine is a widely used local anaesthetic reported to exert a biphasic effect on the microvasculature with contraction at low concentrations and relaxation at high concentrations. There is a need for pharmacologic tools able to counteract local arterial vasoconstriction. In this study, the contractile effect of ropivacaine and lidocaine were investigated in vitro on isolated human arteries. Experiments were performed on 43 internal mammary artery (IMA) rings obtained from 22 patients and on 14 radial artery (RA) rings from 7 patients. The rings were mounted in organ baths and isometric contractile activity was measured. Experiments were conducted by cumulative adding ropivacaine or lidocaine (1.5 x 10(-5) M; 4.5 x 10(-5) M; 1.5 x 10(-4) M; 4.5 x 10(-4) M; 1.5 x 10(-3) M; 4.5 x 10(-3) M; 1.5 x 10(-2) M) to the organ baths. The endothelium was mechanically removed in 19 IMA rings and in 9 RA rings. Ropivacaine and lidocaine produced a biphasic response with contraction at low concentrations (1.5 x 10(-5)-1.5 x 10(-3) M) and release of the maximal contraction at higher concentrations. No statistically significant differences in contractile or relaxing effects were seen between the two drugs. Removal of the endothelium did not significantly affect contractile activity. In this study of human mammary artery preparations, ropivacaine is not a stronger vasoconstrictor than lidocaine.

Amides↗
PubMed1993

Morphologic development of experimental cholesteatoma.

Using light microscopy, we studied the morphologic events of cholesteatoma progression 8 months after ligation of the ear canal in 14 Mongolian gerbils. Although we observed a wide range of progression, four stages of morphologic development could be clearly distinguished among the 28 specimens: stage I, an orthokeratotic plug in the ear canal without tympanic membrane involvement; stage II, partial retraction of the tympanic membrane; stage III, the interface between cholesteatoma encapsulated within the tympanic membrane and mucosal membranes covering the promontorial wall of the middle-ear cavity was characterized by a buildup of granulation tissue with prominent macrophage infiltration; and stage IV, bone destruction. Chronic inflammation was observed in some but not all stage II to IV cases. Our results indicate that hyperkeratosis is a primary event in cholesteatoma development, that the development of the granulation tissue with activated macrophages may be responsible for the bone destruction, and that acute or chronic inflammation is not a prerequisite for the development of cholesteatoma or the bone resorptive process.

Animals↗
PubMed1992

Elevated uptake of low density lipoproteins by human lung cancer tissue in vivo.

In order to explore new treatment modalities for cancer, it is important to identify qualitative or quantitative differences in metabolic processes between normal and malignant cells. Previous in vitro and in vivo studies have shown that acute myelogenous leukemia cells have elevated receptor-mediated uptake of low density lipoproteins (LDL), compared to normal WBC. High receptor-mediated uptake of LDL by certain cancer cells in tissue culture and experimental tumors in animals in vivo has also been demonstrated. The present study was undertaken to compare the in vivo assimilation of LDL by human lung cancer tissue with that by surrounding lung tissue. Ten patients with newly diagnosed lung tumors, scheduled for surgery, received an i.v. injection of [14C]sucrose-labeled LDL. Following cellular uptake and degradation of the LDL particle, the radiolabeled sucrose moiety remains trapped in the lysosomal compartment, making this labeling technique useful for in vivo studies of tissue uptake of LDL. Radioactivity was determined in plasma and in tissue biopsies obtained at surgery 1-3 days after injection. The uptake of radioactivity in lung cancer tissue was elevated (1.5-3.0-fold), compared to surrounding tissue, in 7 of 9 patients with primary lung cancer. The most rapid preoperative disappearance of radioactivity from plasma was found in 2 patients with large tumors exhibiting high LDL uptake, relative to normal lung tissue. These findings support the hypothesis that the selectivity of cytotoxic agents can be enhanced also in nonhematological malignancies by administering the drugs incorporated in LDL particles.

Adult↗
PubMed1992

An outbreak of Klebsiella oxytoca septicemias associated with the use of invasive blood pressure monitoring equipment.

Seven cases of septicemia with piperacillin-resistant Klebsiella oxytoca (PRKO) occurred at 2-monthly intervals in a thoracic surgery intensive care unit. All PRKO isolates were serotyped, and phenotyped with a biochemical typing system. Only one patient in the unit was found to be colonized in stool or respiratory tract with PRKO, and this strain was different from the septicemia strains in phenotype though not in serotype. Environmental cultures, from humidifiers, oxygenators, pressure transducers, etc. were negative. PRKO of the epidemic phenotype was recovered from several non-patient transducer domes. The outbreak ended when transducer heads were disinfected and the use of non-patient domes was abolished.

Adult↗
PubMed1991

Barrett's mucosa in conjunction with squamous carcinoma of the esophagus.

Fifty esophagectomies (32 specimens with squamous cell carcinoma and 18 with adenocarcinoma) were reviewed for the presence of Barrett's mucosa. The whole resected specimens were cut, and a total of 1677 blocks (measuring up to 4.0 x 0.5 cm) were obtained. In resections with squamous cell carcinoma, a mean of 33.6 sections (range, 16 to 55 sections) were excised, and in those with adenocarcinomas, a mean of 33.4 sections (range, ten to 60 sections) were cut. Barrett's mucosa (without or with dysplasia) was present in all 18 specimens with an adenocarcinoma (100%) and in 13 of the 32 specimens (40.6%) with squamous cell carcinoma. In ten of the 13 specimens with squamous cell carcinoma, adjacent areas with high-grade squamous cell dysplasia were found. The squamous cell carcinoma and/or the adjacent squamous cell dysplasia were found separated from the Barrett's mucosa by normal squamous epithelium, supporting the view that these two lesions are not related to one another. Early clinical and experimental data showed that squamous cell dysplasia antedated the development of squamous cell carcinoma in that organ. One possible suggestive of these findings is that the detection of a Barrett's esophagus (without or with dysplasia) should prompt the endoscopist also to examine carefully the rest of the esophagus to exclude mucosal alterations possibly connected with squamous cell carcinogenesis in that organ.

Adenocarcinoma↗
PubMed1991

Further studies on the musculo-fibrous anomaly of the Barrett's mucosa in esophageal carcinomas.

A total of 50 esophagi with carcinoma were reviewed for the presence of histological changes in the subepithelial tissues of the Barrett's mucosa. Those changes consisted in the thickening of the muscularis mucosae, the presence of muscle fibres in the lamina propria mucosae, fibrosis of the submucosa and sometimes total obliteration of the subepithelial tissues by collagen-rich sclerosis. Those changes have been connoted as "musculo-fibrous anomaly". Barrett's mucosa was present in all 18 specimens with adenocarcinoma and in 13 of the remaining 32 specimens with squamous cell carcinoma. Musculo-fibrous anomaly of the Barrett's mucosa occurred in all 18 specimens with adenocarcinoma and in 10 of the 13 specimens with a concomitantly growing squamous cell carcinoma. Esophageal and metaplastic glands were surrounded, compressed and deformed by the fibrotic tissue. The histological changes described explain the difficulties in the differential diagnosis--in biopsy specimens--between normal glands or glands with dysplastic changes "trapped" in the collagen-rich fibrotic tissue and true invasive adenocarcinoma of the Barrett's esophagus.

Adenocarcinoma↗
PubMed1991

Incidence of hepatitis and seroconversion to hepatitis C virus after open-heart surgery in transfused and non-transfused patients in Sweden.

The transmission of non-A, non-B hepatitis (NANB)/hepatitis C virus (HCV) was studied in patients undergoing open-heart surgery and related to the reception of blood products and hospitalization and surgery per se. Posttransfusion hepatitis NANB was noticed in 17/390 (4.4%) patients receiving heterologous blood and 8/16 tested became positive for anti-HCV (Ortho HCV ELISA), all within 5 months after onset of hepatitis. Among patients with normal ALAT before surgery and during follow-up, who had received heterologous blood, 1/50 seroconverted after 6 months. This patient probably had a subclinical HCV infection, or possibly a temporary non-specific anti-HCV reactivity with a maximum optical density/cut-off ratio (OD/CO) of 1.2, whereas all posttransfusion hepatitis C cases had OD/CO ratios greater than 4. No hepatitis occurred among the 92 non-transfused patients and no seroconversion was found in any of 62 non-transfused patients tested 6 months after the operation. It was concluded that (1) hospitalization and surgery per se does not seem to offer a risk of hepatitis NANB/C, and (2) seroconversion to for HCV occurs in only 50% of Swedish patients with acute posttransfusion NANB hepatitis.

Alanine Transaminase↗
PubMed1991

Evaluation of epidermal hyperproliferation in patients with cholesteatoma.

Whether cholesteatoma development in chronic otitis media may be part of a generalized hyperproliferation of the epidermis was examined. The renewal time of the stratum corneum was determined in 24 patients presenting with chronic middle ear disease with cholesteatoma. These patients were compared with two control groups: one with chronic otitis media without cholesteatoma and one with otosclerosis. Dansyl chloride was applied to the back of the shoulder beneath occlusive patches for 2 days and the time it took the fluorescing label under ultraviolet light to disappear was measured. The depth of stratum corneum was determined with a standardized tape by measuring the number of strippings until no remaining fluorescing label was visible. This was also analysed with punch biopsies and fluorescence microscopy. However the cholesteatoma patients demonstrated no significant alterations in any of the studied parameters in comparison with the control groups. Based on our techniques and the data obtained there is no evidence of an epidermal hyperproliferative predisposition in patients with cholesteatoma.

Adult↗
PubMed1990

A clinical comparison of hydrocortisone butyrate with oxytetracycline/hydrocortisone acetate-polymyxin B in the local treatment of acute external otitis.

In a single blind, randomized study, 46 patients with acute external otitis were treated with either oxytetracycline/hydrocortisone with polymyxin B (TPB) or hydrocortisone-17-alpha-butyrate eardrops for 7 days. Pseudomonas pyocyanea, Staphylococcus epidermidis and Staph. aureus were the microorganisms most frequently found in the ear canal. Fungi were not found in any culture. The overall cure rate was 80%. No significant difference in therapeutic efficacy was noted between the preparations except regarding Staph. aureus, which was cultured from 17% of the patients. Although the butyrate solution did not contain any antibiotic supplement, it seemed to be more effective than TPB in treating the staphylococcal infections. These findings suggest that such other factors as the hydrogen ion concentration, the steroid potency or the vehicle per se are of importance for the successful treatment of acute external otitis.

Acute Disease↗
PubMed1990

Serum levels of the aminoterminal propeptide of type III procollagen and hyaluronan during resolving and nonresolving posttransfusion non-A, non-B hepatitis.

Serum levels of the aminoterminal propeptide of type III procollagen (PIIINP) and hyaluronan were analysed before and during the acute, recovery and chronic phases of non-A, non-B (NANB) posttransfusion hepatitis (PTH) in 13 patients. All patients were discovered during a prospective study on NANB PTH in patients undergoing open-heart surgery. 7/13 (54%) patients resolved their hepatitis within 6 months after onset, whereas 6/13 (46%) went on to chronic hepatitis. In 5 of these 6 patients a liver biopsy during the chronic phase of the hepatitis showed chronic active hepatitis in 2 and chronic persistent hepatitis in 3. During the acute NANB PTH phase the mean serum PIINP level rose significantly as compared to prehepatitis levels and to levels in a reference group not developing hepatitis. Neither PIIINP levels nor hyaluronan levels, however, could differentiate patients with resolving from patients with nonresolving hepatitis. These markers should, however, be further evaluated as potential markers for development of fibrosis/cirrhosis during chronic hepatitis.

Aged↗
PubMed1989

Serum levels of cloxacillin and benzylpenicillin in adults undergoing open-heart surgery.

Serum levels of cloxacillin and benzylpenicillin were monitored in 35 consecutive adult patients undergoing elective open-heart surgery. Serial serum samples were analyzed during a 24-hour period. After oral intake of cloxacillin and phenoxymethylpenicillin on the preceding evening, very low concentrations remained in serum at the start of operation. Such preoperative medication is inappropriate. Intravenously administered cloxacillin (2 g) and benzylpenicillin (3 g) appeared to be adequate during the first 4 hours of surgery, as the serum half-life of the drugs was twice as long in the patients as in healthy adults, but repetition of the doses is recommended for further antibiotic protection during surgery.

Administration, Oral↗
PubMed1988

Non-A, non-B hepatitis after open-heart surgery in Stockholm: declining incidence after introduction of restrictions for blood donations due to the human immunodeficiency virus.

In 1979 the incidence of non-A, non-B (NANB) posttransfusion hepatitis (PTH) in Stockholm was 19%. After the discovery of HIV the Swedish Board of Health put forward new regulations for blood donations and since 1985 has enforced testing for HIV on all blood units. To find out if these measures have had any impact on the incidence of NANB PTH, 316 patients transfused during open-heart surgery from December 1985 to November 1986 were followed prospectively. PTH due to the NANB agent(s) developed in 4.4% (14/316). A significantly higher mean number of blood units had been given to patients undergoing coronary artery bypass surgery in whom NANB PTH developed than in those who did not develop the infection. The mean number of blood units transfused during open-heart surgery in Stockholm had decreased from 16 in 1979 to 10 in 1985-1986. The number of NANB PTH cases/1,000 blood units transfused declined from 12 to 4 during the same period. Thus, both the reduced number of blood units given during open-heart surgery and the new restrictions for blood donors seem to have been effective in reducing the risk for NANB PTH in Stockholm during the 1980s.

Adult↗
PubMed1988

Long-term clinical results after combined aortic and mitral valve replacement.

The results after 282 consecutive double (aortic & mitral) valve replacements (DVR) are compared with our previously reported experience after mitral (MVR, n = 810) and aortic valve replacement (AVR, n = 1753). All but one patient received Björk-Shiley valves. The follow-up which closed on August 1, 1985 was 99.3% and covered 16,869 patient-years (mean 6.3 years/patient). Autopsies were performed in 74% of all fatalities. Early mortality rates were identical in the three patient groups, and late mortality did not differ between MVR and DVR patients. The fraction of valve-related mortality was similar in all groups. Anticoagulant-related bleeding was equally common in all patient groups. The incidences of thromboembolism, reoperation and valve failure did not differ between MVR and DVR patients, but were significantly higher than among AVR patients. With the exception of a slightly increased incidence of prosthetic valve endocarditis, the results after DVR equal those after MVR. In cases with severe mitral valve disease but borderline aortic valve disease, primary DVR is clearly justified and eliminates the need for, and risks of, a secondary AVR.

Aged↗
PubMed1987

Acute traumatic tympanic membrane perforations. Cover or observe?

The influence of a paper prosthesis on healing in acute traumatic tympanic membrane perforations was studied in 60 patients randomly selected for a treatment group or a control group. The majority (42 [70%] ) were seen within two days. All patients were treated with oral antibiotics for ten days. The overall healing rate two months after the trauma was 94% (37 of 39 patients). No significant difference between the study group and the control patients was observed. Intermittent secretion was seen in six patients but did not influence the outcome. The perforations occurred in patients with normally sized mastoid air cell systems as seen on roentgenograms. We conclude that acute traumatic tympanic membrane perforations do not need to be treated routinely with paper patching.

Acute Disease↗