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Biomedical subjects

J Berg

Publications and source records attributed to J Berg.

At least 55 records · Page 3Linked to original sources
PubMed1998

Beat-to-beat QRS variability in the 12-lead ECG and the detection of coronary artery disease.

The aim of this article was to study beat-to-beat QRS variability in patients with ischemia and old myocardial infarction using the 12-lead resting electrocardiogram (ECG). The variability analysis was based on beats that have been synchronized in time with an iterative alignment technique. The QRS variability was measured in patients submitted for myocardial scintigraphy. Those with a normal myocardial scintigraphy (called NO, n = 34, mean age 57 years, 23 women) were compared with a group with both myocardial infarction and exercise-induced ischemia (called ISCINF, n = 27, mean age 57 years, 5 women). The mean QRS variability was somewhat smaller in lead I in ISCINF than in NO, and there was no statistically significant difference in QRS variability among the groups in leads II, III, and V1-V6. Using a multivariate approach, the joint variability in leads I, II, II, and V1-V6 was used for calculating receiver operating characteristics based on a leave-one-out procedure. The sensitivity for detecting coronary artery disease was 75% at a specificity of 50%. It is concluded that beat-to-beat QRS variability in the 12-lead ECG does not discriminate between the presence and absence of coronary artery disease sufficiently well for clinical purposes.

Coronary Disease↗
PubMed1998

Principles of oncologic orofacial surgery.

The most common orofacial tumors of dogs are malignant melanoma, squamous cell carcinoma, fibrosarcoma, osteosarcoma, and acanthomatous epulis. These tumors vary significantly in their metastatic potential, but are consistently locally invasive. Bone involvement is common, and complete excision often requires partial mandibulectomy or partial maxillectomy. Survival times after surgery are most strongly influenced by tumor type (or metastatic rate) and tumor location. Recent large retrospective studies have reported median survival times ranging from 4.6 to 26 months. The most common oral tumor of cats is squamous cell carcinoma. This is a highly invasive tumor that occasionally can be effectively treated with surgery alone, but that often requires a combination of surgery and radiation therapy.

Animals↗
PubMed1998

Pharmacokinetic interaction between ritonavir and indinavir in healthy volunteers.

The pharmacokinetic interaction between indinavir and ritonavir was evaluated in five groups of healthy adult volunteers to explore the potential for twice-daily (b.i.d.) dosing of this combination. All subjects received 800 mg of indinavir every 8 h (q8h) on day 2. In addition, subjects in group I received one dose of 800 mg of indinavir on day 1 and 800 mg of indinavir q8h on day 17. Subjects in Groups II and IV each received one dose of 600 mg of indinavir on days 1 and 17, and subjects in groups III and V each received one dose of 400 mg of indinavir on days 1 and 17. During days 3 to 17, ritonavir placebo or ritonavir at 200, 300, 300, or 400 mg q12h was given to groups I, II, III, IV, and V, respectively. Ritonavir at steady state probably inhibited the cytochrome P-450 3A metabolism of indinavir and substantially increased plasma indinavir concentrations, with the area under the plasma concentration-time curve (AUC) increasing up to 475% and the peak concentration in serum (Cmax) increasing up to 110%. The Cmax/trough concentration ratio decreased from 50 in standard q8h regimens to less than 14 when indinavir was administered with ritonavir. For a constant indinavir dose, an increase in the ritonavir dose yielded similar indinavir AUCs, Cmaxs, and concentrations at 12 h (C12s). For a constant ritonavir dose, an increase in the indinavir dose resulted in approximately proportional increases in the indinavir AUC, less than proportional increases in Cmax, and slightly more than proportional increases in C12. Ritonavir reduced between-subject variability in the indinavir AUC and trough concentrations and did not affect indinavir renal clearance. With the altered pharmacokinetic profile, indinavir likely could be given as a b.i.d. combination regimen with ritonavir. This could potentially improve patient compliance and thereby reduce treatment failures.

Adolescent↗
PubMed1997

Effect of timing of postoperative chemotherapy on survival of dogs with osteosarcoma.

BACKGROUND: After excision of primary tumors, initiation of chemotherapy for micrometastases is often delayed for 2 to 4 weeks to permit patient recovery and early healing of the surgical wound. However, studies using murine tumors have indicated that removal of a primary tumor may cause increased cell proliferation within micrometastases during the first 7 to 10 days after surgery, potentially rendering the micrometastases more susceptible to chemotherapy. Clinical trials assessing the value of early postoperative initiation of chemotherapy for human breast carcinoma have yielded conflicting results. Osteosarcoma of dogs is a naturally occurring model for human tumors likely to have micrometastases at the time of diagnosis. METHODS: Before surgery, 102 dogs with osteosarcoma were randomized to receive cisplatin and doxorubicin chemotherapy beginning either 2 days or 10 days after amputation. Survival analysis was performed for each treatment group and for a historic control group comprised of 162 dogs treated by amputation alone. RESULTS: Median survival times for dogs treated by amputation alone and for dogs receiving chemotherapy beginning 2 or 10 days after surgery were 5.5, 11.5, and 11.0 months, respectively. Survival was significantly longer for each of the two groups of dogs receiving chemotherapy than for control dogs (P < 0.0001). There was no significant difference in survival between treatment groups (P = 0.727). CONCLUSIONS: These results do not disprove the theory that removal of a primary tumor alters the growth kinetics of metastases, but do imply that there is no substantial advantage to early postoperative initiation of adjuvant chemotherapy for spontaneous tumors of large species.

Amputation, Surgical↗
PubMed1997

Surface Force Studies of Langmuir-Blodgett Cellulose Films

The interactions between cellulose surfaces, between chitosan-coated surfaces, and between one cellulose surface and one chitosan-coated surface have been studied using the interferometric surface force apparatus (SFA). The cellulose surfaces were prepared by depositing trimethylsilyl cellulose on hydrophobized mica using the Langmuir-Blodgett technique. The surfaces were desilylated in a humid HCl atmosphere to obtain regenerated cellulose. ESCA measurements and wetting studies demonstrated that the desilylation process was effective. Scanning force microscopy studies showed the cellulose surfaces to be smooth with a root-mean-square roughness of 0.16 nm. Surface force and ellipsometry measurements illustrate that the cellulose film swells considerably in humid air and in water, suggesting that it is mostly amorphous. The interaction between two cellulose surfaces is dominated by a steric repulsion caused by a few dangling tails. On separation an attractive force was present both between two cellulose surfaces and between one cellulose surface and one chitosan surface. The long-range interaction between cellulose and chitosan was shown to be attractive.

Journal Article↗
PubMed1997

Isoenzyme-specific cyclooxygenase inhibitors: a whole cell assay system using the human erythroleukemic cell line HEL and the human monocytic cell line Mono Mac 6.

NSAIDs inhibit the conversion of arachidonic acid into Prostaglandin G2 and Prostaglandin H2 which is catalyzed by the enzyme cyclooxygenase (COX). Two genetically distinct isoforms have been discovered, COX-1 and COX-2. While COX-1 is thought to account for homeostatic amounts of eicosanoids, COX-2 is induced during inflammation leading to pathologic amounts of eicosanoids. Since NSAIDs inhibit both COX isoforms, antiinflammatory drug research has refocused to discovering COX-2 inhibitors that do not inhibit COX-1. For this purpose, we have developed a whole cell assay system using the human erythroleukemic cell line HEL as a source for COX-1 and the human monocytic cell line Mono Mac 6 as a source for COX-2. Mono Mac 6 cells express high amounts of COX-2 upon stimulation with lipopolysaccharide (LPS) in the absence of any detectable COX-1 protein. On the other hand, we find HEL cells to naturally express COX-1 protein, but not COX-2. Testing of a panel of NSAIDs as well as some COX-2 specific inhibitors showed that this assay system is suitable for identifying compounds that selectively inhibit either COX-1 or COX-2. This test system offers the advantage of assessing COX-1 and COX-2 inhibitors within the human species, within a similar test set-up, and circumvents the need for tedious purification of either platelets or peripheral blood monocytes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

An evaluation of a self-management program for adults with asthma.

The purpose of this study was to evaluate the impact of a self-management program for adults with moderate to severe asthma on compliance with inhaled, prescribed, nonemergency medications; asthma symptoms; and airway obstruction. In this controlled experimental study, 55 subjects from a rural community were randomized to one of two groups. Self-efficacy theory served as the framework for this study. Primary measures included the Metered Dose Inhaler (MDI) Chronolog, a journal of daily asthma concerns, and a peak-flow meter to appraise airway obstruction. Secondary measures included the Asthma Self-Management Assessment Tool (ASMAT) and the Self-Efficacy for Asthma Management Scale (SEAMS). These measures were completed pre- and post-intervention. Data analysis using descriptive and inferential statistics revealed that subjects receiving the self-management program increased compliance with inhaled medications (U = 271, p = .043).

Adolescent↗
PubMed1996

Microsporidia in humans.

Explore the source record for details and available documents.

AIDS-Related Opportunistic Infections↗
PubMed1996

Canine osteosarcoma: amputation and chemotherapy.

One of the most important advances in veterinary oncology during the past 10 years has been the use of adjuvant chemotherapy for treatment of the micrometastases of canine osteosarcoma. This article reviews the biologic behavior of osteosarcoma and discusses chemotherapy with the two agents known to be effective: cisplatin and doxorubicin.

Amputation, Surgical↗
PubMed1996

Transcranial Doppler detection of microemboli in prosthetic heart valve patients: dependency upon valve type.

Transcranial Doppler ultrasound has revealed the existence of cerebrovascular microemboli in asymptomatic patients with prosthetic heart valves. We investigated the relation between the presence and number of emboli signals and valve type. Patients with six types of prosthetic valves (Björk-Shiley monostrut, Medtronic-Hall, Carbomedics, ATS, Carpentier-Edwards standard, Carpentier-Edwards supraannular) were examined using transcranial Doppler ultrasound in two centers. The monitoring time was 30 min over the right middle cerebral artery. All patients were stabilized on warfarin at the time of study. Microemboli signals were identified by their characteristic audiovisual signal and on subsequent spectral analysis, based on accepted criteria. A standard neurologic questionnaire was completed by all patients. The prevalence of microemboli signals varied between 49% (Medtronic Hall) and 97% (Björk-Shiley monostrut), while their number varied between 1 [0-3] (Carpentier-Edwards standard) and 187 [136-240] (Björk-Shiley monostrut) per hour (median and 95% CI). Both parameters were significantly higher in patients with Björk-Shiley monostrut valves compared to the other patient groups. There were no significant differences in the prevalence of neurologic complications among the groups examined (overall 16%), or in emboli numbers between symptomatic and asymptomatic patients. The prevalence and quantity of microemboli signals in patients with prosthetic heart valves, as detected by transcranial Doppler, is dependent upon valve type. The clinical significance of these microemboli signals remains to be further evaluated.

Aged↗
PubMed1996

Disseminated microsporidiosis especially infecting the brain, heart, and kidneys. Report of a newly recognized pansporoblastic species in two symptomatic AIDS patients.

Microsporidia have emerged as important opportunistic AIDS pathogens of the alimentary, respiratory, and urinary tracts. Although nonhuman mammalian microsporidia infections typically include encephalitis, CNS microsporidiosis has not been reported in patients with AIDS. A 33-year-old white male and an 8-year-old black girl presented with seizures and declining mental status. Central nervous system (CNS) imaging studies revealed small peripherally and diffusely enhancing lesions present for at least 2 and 4 months before death, respectively. Both patients expired despite empirical anti-toxoplasma therapy. Their brains contained innumerable soft gray matter lesions that consisted of central areas of necrosis, filled with free spores and spore-laden macrophages, surrounded by microsporidia-infected astrocytes. The complete autopsy of the child also revealed necrotizing and sclerosing cardiac and renal microsporidiosis and infection of the pancreas, thyroid, parathyroids, liver, spleen, lymph nodes, and bone marrow. Infected cells included astrocytes, cardiac myocytes, epithelium, endothelium, vascular smooth muscle cells, hepatocytes, adipocytes, Schwann cells, and macrophages. Light and electron microscopic studies revealed pansporoblastic development within thick-walled sporophorous vacuoles of parasite origin. Although most similar to Pleistophora sp and Thelohania sp, this microsporidian is different from any known species. Microsporidiosis should be considered as the possible cause of a wide range of diseases in AIDS patients, including CNS, cardiac, and renal.

AIDS-Related Opportunistic Infections↗