Biomedical subjects

J Jensen

Publications and source records attributed to J Jensen.

At least 181 records · Page 10Linked to original sources

PubMed1996

Analgesic effects of adenosine during exercise-provoked myocardial ischaemia.

The analgesic potential of adenosine during myocardial ischaemia was studied in patients with coronary artery disease and exercise-limiting angina pectoris. Patients were given a low dose of adenosine or placebo in a double-blind cross-over fashion by continuous i.v. infusion before and during two exercise tests. Adenosine decreased chest pain by 45 +/- 13% (p < 0.02) while heart rate-blood pressure product and electrocardiographic signs of myocardial ischaemia did not change. Ten healthy volunteers received increasing doses of adenosine by continuous i.v. infusion. The heat pain threshold increased in skin covering the chest (p < 0.03) and also tended to increase at the left thenar eminence (p < 0.07). In conclusion, the neuromodulator adenosine can therefore act as an analgesic in myocardial ischaemia.

Adenosine↗

PubMed1996

Synovial metastasis: diagnosis by fine-needle aspiration cytologic investigation.

Synovial metastases are a rare occurrence. Only 28 cases have been reported in the literature, 10 of which were diagnosed by fluid cytologic evaluation. We discuss 2 additional cases in which the diagnosis was made by fine-needle aspiration cytologic investigation. The first case is of a 47-yr-old man with small-cell carcinoma of the lung metastatic to the right knee joint; the second is of a 71-yr-old man with non-Hodgkin's mixed-cell nodular lymphoma also involving the right knee joint. The clinical features of these cases are similar to previously published instances of secondary synovial tumor, namely in regard to sex distribution (14 male and 16 female patients), age range (13-96 yr, mean 59 yr), and histologic types (adenocarcinoma, 13 cases; squamous-cell carcinoma, 4; lymphoma, 3; renal clear-cell carcinoma, 3; unknown origin, 2; rhabdomyosarcoma, 1; melanoma, 1; chordoma, 1; pulmonary clear-cell carcinoma, 1; and Ewing's sarcoma, 1). The condition usually has poor prognosis, with average patient survival of < 5 mo.

Aged↗

PubMed1996

Chlorophenols in the terrestrial environment.

Chlorophenols are presently widespread in the environment. Even in the most remote natural environments, the presence of chlorophenols in both aquatic and terrestrial food chains has been recorded. These pervasive compounds have been used for a wide range of domestic, agricultural, and industrial purposes for more than 50 years. In addition to industrial production and usage, chlorophenols are produced from naturally occurring phenols as a result of chlorine bleaching of wood pulp in the paper industry and through the chlorination of domestic water supplies and swimming pools. It must be emphasized that chlorophenols, although a local problem in some areas, generally cannot be considered a major environmental problem today because their use is prohibited or restricted in many countries. Future reduction in the use of the herbicidal phenoxy acids will further minimize their levels in the terrestrial environment. Because of the long persistence and high toxicity of pentachlorophenol in particular, however, it is important that the discharge of chlorophenols to the terrestrial environment by way of sewage sludge or pulp mill effluents be maintained at their current levels or even reduced to lower levels.

Animals↗

PubMed1996

Characterization of tobacco withdrawal symptoms: transdermal nicotine reduces hunger and weight gain.

The accurate assessment of both tobacco withdrawal and the impact of the nicotine patch on withdrawal may be compromised by attrition of subjects, or by subjects smoking during withdrawal. To reduce these occurrences, 211 participants were provided with intensive cessation counseling while trying to quit smoking with either nicotine (21 mg) or placebo transdermal patches. Subject attrition was low, with 80.5% of participants continuing through the 5-week study period. Abstinence rates were also high over this period (75% and 61% in active and placebo groups, respectively). In this multisite, double-blind trial, withdrawal severity was assessed using a nine-item daily self-report questionnaire, and abstinence was confirmed via CO monitoring. Abrupt smoking cessation increased multiple tobacco withdrawal symptoms/signs including craving for cigarettes, irritability, anxiety, appetite, sleep disruption, difficulty concentrating, restlessness, depression, and impatience. Treatment with transdermal nicotine reduced craving for cigarettes, anxiety, irritability, and appetite, as well as weight gain (1.85 versus 2.88 kg mean gain over 4 weeks in active and placebo groups, respectively).

Administration, Cutaneous↗

PubMed1996

Listeria monocytogenes in bovine mastitis. Possible implication for human health.

During the 23-year period 1972 through 1994 quarter milk samples from 1,132,958 cows originating from 36199 herds were examined for the presence of Listeria monocytogenes. Through the period the reference population amounted to 12,742,600 cow years and 401,682 herd years. The percentage of cows infected with L. monocytogenes varied from 0.01 to 0.1% (mean 0.04%) and of herds with an infected cow from 0.2 to 4.2% (mean 1.2%) through the period, showing a low but constant level of infection. A comparison of 33 isolates from bovine mastitis and 27 human clinical isolates was made by sero- and ribotyping. Serotyping showed that all bovine and 17 (63%) of the human isolates belonged to serogroup 1, whereas 10 (37%) of the human isolates belonged to serogroup 4. Ribotyping using EcoRI as restriction enzyme divided the 60 isolates into 16 different types, 7 of which were found among both the bovine and human types. The combination of the typing methods showed that 26 (79%) bovine and 13 (48%) human isolates shared common types. This study showed that a low but constant percentage of Danish dairy herds have cows infected with L. monocytogenes and that some of the bovine types could be found among types causing human infections.

Animals↗

PubMed1996

Vasoconstrictive effects of native tachykinins in the rainbow trout, Oncorhynchus mykiss.

The role of trout substance P (tSP) and neurokinin A (tNKA) in cardiovascular regulation was investigated in the rainbow trout, Oncorhynchus mykiss, in vivo and in vitro. In vivo, the coeliac arterial and ventral aortic relative blood flows were measured with Doppler flow probes, and blood pressure was measured via a cannula inserted into the dorsal aorta. tSP (0.1 and 1 nmol kg-1) and tNKA (1 nmol kg-1) increased both systemic and coeliac vascular resistances, leading to hypertension and bradycardia. In addition, cardiac output was decreased. The mammalian NK1 tachykinin receptor antagonist CP-96,345 did not affect the responses to tSP or tNKA. In vitro perfusions of the dorsal aortic and coeliacomesenteric vascular beds were performed using peristaltic pumps. The dorsal aortic vascular resistance was dose-dependently increased following infusion of the two peptides (pD2 values 7.6 +/- 0.1 and 7.3 +/- 0.1 for tSP and tNKA, respectively). Tetrodotoxin did not affect the tSP-induced hypertension. Increases in coeliac vascular resistance caused by tSP was correlated with stomach contractions when measurement of intragastric pressure was made using an inserted balloon. In conclusion, native SP and NKA are potent vasoconstrictors of rainbow trout vasculature, a property quite unusual to tachykinins compared with the vasodilation normally seen in mammals.

Amino Acid Sequence↗

PubMed1996

An extended Le Fort I osteotomy for correction of midface hypoplasia: a modified technique and results in 35 patients.

PURPOSE: This report analyzes the long-term results of a transoral high Le Fort I osteotomy (mean observation period, 37 months). PATIENTS AND METHODS: Thirty-five patients were treated with high Le Fort I osteotomies in which the zygomatic prominence was included in the osteotomy and advanced together with the maxilla. Twenty of the 35 patients were seen for long-term follow-up (mean, 37 months), which included clinical and radiographic examinations and anamnestic evaluation of the results. In nine patients it was possible to evaluate stability of the osteotomy by cephalometry. RESULTS: The treatment results clinically appeared stable, with good occlusion and, in most patients, improved function of the masticatory system. Patients reported satisfactory esthetic results. Radiologically the SNA angle was unaltered in six of seven non-CLP (cleft lip and palate) patients and was decreased in two of two CLP patients. There were few complications; one patient had the maxilla reoperated because of a lack of osseous healing and one patient had pulp necrosis of three maxillary teeth. CONCLUSION: The results achieved with the described method indicate that the use of minor modifications of routine surgical procedures in conventional orthognathic surgery can improve esthetic results in patients with extended midfacial hypoplasia.

Adolescent↗

PubMed1996

Vascular applications of telepresence surgery: initial feasibility studies in swine.

PURPOSE: Telepresence surgery is a novel technology that will allow procedures to be performed on a patient at locations that are physically remote from the operating surgeon. This new method provides the sensory illusion that the surgeon's hands are in direct contact with the patient. We studied the feasibility of the use of telepresence surgery to perform basic operations in vascular surgery, including tissue dissection, vessel manipulation, and suturing. METHODS: A prototype telepresence surgery system with bimanual force-reflective manipulators, interchangeable surgical instruments, and stereoscopic video input was used. Arteriotomies created ex vivo in segments of bovine aortae or in vivo in femoral arteries of anesthetized swine were closed with telepresence surgery or by conventional techniques. Time required, technical quality (patency, integrity of suture line), and subjective difficulty were compared for the two methods. RESULTS: All attempted procedures were successfully completed with telepresence surgery. Arteriotomy closures were completed in 192+/-24 sec with conventional techniques and 483+/-118 sec with telepresence surgery, but the precision attained with telepresence surgery was equal to that of conventional techniques. Telepresence surgery was described as intuitive and natural by the surgeons who used the system. CONCLUSIONS: Blood-vessel manipulation and suturing with telepresence surgery are feasible. Further instrument development (to increase degrees of freedom) is required to achieve operating times comparable to conventional open surgery, but the system has great potential to extend the expertise of vascular surgeons to locations where specialty care is currently unavailable.

Animals↗

PubMed1996

Survivorship analysis of cemented total condylar knee arthroplasty. A long-term follow-up report on 348 cases.

Survivorship analysis was used in the evaluation of 348 consecutive primary total condylar knee arthroplasties (total knee arthroplasties) performed on 253 patients in a 27-month period, with a maximum follow-up period of 12 years. The diagnosis was osteoarthrosis in 184 cases and rheumatoid arthritis in 164 cases. Ten patients (10 total knee arthroplasties) were lost to follow-up evaluation. The endpoint was defined as prosthesis not in situ. The variables considered were age, sex, body mass index, and diagnosis. The overall cumulative survival rate was 92%. The survival rate of the osteoarthrosis group was significantly higher (97%) than that of the rheumatoid arthritis group (87%). None of the other variables affected survival rate significantly.

Aged↗

PubMed1996

Effects of behavioral and pharmacological treatment on smokeless tobacco users.

The purpose of this study was to examine the effects of 2 mg of nicotine polacrilex versus placebo gum and of group behavioral treatment versus minimal contact on cessation of smokeless tobacco use. Participants (N = 210) were randomly assigned 1 of the 4 treatment conditions. Withdrawal symptoms were assessed throughout the treatment. Follow-up assessments were made at 1, 6, and 12 months posttreatment. Survival curve analysis showed that any of the 3 treatment groups involving group behavioral therapy or placebo gum were equally effective and superior to the minimal contact plus 2 mg of nicotine gum treatment in terms of abstinence. On the other hand, withdrawal symptoms were significantly reduced by nicotine gum, compared with placebo during the initial phases of cessation. The ineffectiveness of nicotine gum on treatment outcome may be attributed to its similarity with smokeless tobacco.

Adult↗

PubMed1996

Oral immunization of mice against candidiasis.

Oral immunization with live Candida albicans evoked antibody- and cell-mediated immune responses in gnotobiotic C.B-17 and BALB/c mice. No deaths or systemic candidiasis of endogenous origin were evident in these C. albicans-colonized (pure culture) mice. Histologic examination showed minimal to no infection of the stomach, esophagus, or tongue by C. albicans. Not only were orally immunized mice more resistant to systemic candidiasis (intravenous challenge) than were germfree (nonimmunized) controls, but immunity could be transferred to susceptible mice with immune spleen cells. Oral immunization elicited a Th1-type response in spleen cells and a Th2 response in Peyer's patch lymphocytes. The alimentary tracts of these orally immunized mice remained chronically colonized with C. albicans in spite of the presence of both antibody- and cell-mediated immune responses to C. albicans.

Administration, Oral↗

PubMed1996

Glucose transport and cell surface GLUT-4 protein in skeletal muscle of the obese Zucker rat.

The relationship between 3-O-methyl-D-glucose transport and 2-N-4-(1-azi-2,2,2-trifluoroethyl)-benzoyl-1, 3-bis-(D-mannos-4-yloxy)-2-propylamine (ATB-BMPA)-labeled cell surface GLUT-4 protein was assessed in fast-twitch (epitrochlearis) and slow-twitch (soleus) muscles of lean and obese (fa/fa) Zucker rats. In the absence of insulin, glucose transport as well as cell surface GLUT-4 protein was similar in both epitrochlearis and soleus muscles of lean and obese rats. In contrast, insulin-stimulated glucose transport rates were significantly higher for lean than obese rats in both soleus (0.74 +/- 0.05 vs. 0.40 +/- 0.02 mumol.g-1.10 min-1) and epitrochlearis (0.51 +/- 0.05 vs. 0.17 +/- 0.02 mumol.g-1.10 min-1) muscles. The ability of insulin to enhance glucose transport in fast- and slow-twitch muscles from both lean and obese rats corresponded directly with changes in cell surface GLUT-4 protein. Muscle contraction elicited similar increases in glucose transport in lean and obese rats, with the effect being more pronounced in fast-twitch (0.70 +/- 0.07 and 0.77 +/- 0.04 mumol.g-1.10 min-1 for obese and lean, respectively) than in slow-twitch muscle (0.36 +/- 0.03 and 0.40 +/- 0.02 mumol.g-1.10 min-1 for obese and lean, respectively). The contraction-induced changes in glucose transport directly corresponded with the observed changes in cell surface GLUT-4 protein. Thus the reduced glucose transport response to insulin in skeletal muscle of the obese Zucker rat appears to result directly from an inability to effectively enhance cell surface GLUT-4 protein.

Affinity Labels↗

PubMed1996

Effect of overexpressing GLUT-1 and GLUT-4 on insulin- and contraction-stimulated glucose transport in muscle.

To examine the effects of GLUT-1 on GLUT-4-dependent, insulin-stimulated, and contraction-stimulated 2-deoxy-D-glucose (2-DG) transport, we overexpressed GLUT-1 in metabolically heterogeneous skeletal muscles [red and white tibialis anterior (TA) and extensor digitorum longus (EDL)] via 7 days of chronic electrical stimulation. GLUT-1 was increased 1.6- to 16.4-fold (P < 0.05). Basal 2-DG transport was increased 1.7- to 3.0-fold (P < 0.05) and was equal to (red TA and EDL; P > 0.05) or exceeded insulin-stimulated 2-DG transport by 50% (white TA; P < 0.05) in the control muscles. GLUT-4 was concomitantly overexpressed (2.1- to 4.4-fold; P < 0.05). Insulin-stimulated 2-DG transport was increased 1.6- to 2.5-fold (P < 0.05). During muscle contractions, 2-DG transport increased 9- to 12-fold (P < 0.05) in control muscles, but this was reduced by approximately 25% (P < 0.05) in muscles overexpressing GLUT-1 and GLUT-4 (red TA and EDL). In contrast, in the experiment, white TA contraction-stimulated 2-DG transport was increased 1.7-fold (P < 0.05). Therefore, overexpression of GLUT-1, when GLUT-4 is also overexpressed, does not impair insulin-stimulated 2-DG transport, although contraction-stimulated transport may be reduced in some muscles.

Animals↗

PubMed1996

Vasoactivity and immunoreactivity of fish tachykinins in the vascular system of the spiny dogfish.

Tachykinin control of gut blood flow (measured by pulsed Doppler technique), dorsal aortic pressure, and heart rate were studied in unrestrained spiny dogfish Squalus acanthias injected with the elasmobranch tachykinins scyliorhinin I and II (SCY I and SCY II), the trout tachykinins substance P (SP), and neurokinin A (NKA). Effects on somatic vasculature were measured by in vitro perfusion of the isolated tail. SCY I and trout SP produced hypotension due to a general vasodilation. This caused a transient increase in mesenteric blood flow and a prolonged increase in celiac blood flow. SCY II caused an initial hypertension induced by a general vasoconstriction, followed eventually by an elevated flow in both gut arteries due to dilation of the vascular beds. Trout NKA evoked a short-lasting increase in celiac blood flow due to a decrease in vascular resistance, a late decrease in mesenteric flow due to vasoconstriction, and no effect on the somatic vasculature. None of the peptides affected heart rate. The study demonstrates a significant vasoactive function of fish tachykinins in the vascular system of an elasmobranch species and, in addition, the occurrence of tachykinin receptor subtypes. Immunohistochemistry revealed a NKA/SCY II-like peptide in nerve fibers innervating many vessels, including the celiac and the mesenteric arteries, the gastrointestinal canal, and the heart.

Amino Acid Sequence↗

PubMed1996

Effect of electrical stimulation patterns on glucose transport in rat muscles.

Transport of 2-[3H]deoxy-D-glucose (2-DG) was investigated during supramaximal stimulations of different muscles. In addition, we varied the net stimulation time (NST). In different treatments, NST occupied either 5, 7.5, 10, 15, 20, 30, or 50% of a 20-min stimulation period. After a bolus injection of 3H-labeled 2-DG, the greatest transport occurred in the extensor digitorum longus. In red gastrocnemius (RG; type IIa fibers) and white gastrocnemius (WG; type IIb fibers), the 2-DG transport rate was highest at 10% NST (8- to 12-fold increase) and decreased thereafter. In soleus (type I fibers), the 2-DG transport increased from 5 to 50% NST. Below 30% NST, 2-DG transport was greater in RG and WG muscles than in soleus (P < 0.05). GLUT-4 and 2-DG transport were not correlated during the contractions. Therefore, the percent NST affects 2-DG transport differentially in muscles of varying fiber types, and the transport rate is not related to the GLUT-4 content of the muscles.

Animals↗

PubMed1996

Randomized, double-blind, placebo-controlled trial comparing the response rates of carmustine, dacarbazine, and cisplatin with and without tamoxifen in patients with metastatic melanoma. National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: We designed and conducted a randomized, double-blind, placebo-controlled trial to compare the response rates and survival of patients with metastatic melanoma who received carmustine (BCNU), dacarbazine (DTIC), and cisplatin with tamoxifen, or the same chemotherapy with placebo. PATIENTS AND METHODS: Eligible patients with metastatic melanoma received either BCNU 150 mg/m2 intravenously (i.v.) on day 1, DTIC 220 mg/m2 i.v. daily on days 1 to 3 and on days 22 to 24, and cisplatin 25 mg/m2 i.v. daily on days 1 to 3 and on days 22 to 24 with placebo every 6 weeks, or the same chemotherapy with tamoxifen 160 mg orally daily for 7 days before chemotherapy and 40 mg orally daily throughout the remainder of the treatment cycle. Patients were treated on protocol for up to three cycles depending on the type of response. Assuming that a minimum increase in response rate of 20% would be necessary to conclude that tamoxifen conferred a clinically important benefit, we designed the study with an 80% chance of detecting that difference at the 5% level (two-sided). RESULTS: Between February 1992 and January 1995, 211 patients were accrued, 199 of whom were considered assessable for response and toxicity. The overall response rate was 21% in the placebo group and 30% in the tamoxifen group (P = .187). Complete and partial responses were 3% and 27%, respectively, for the tamoxifen group and 6% and 14%, respectively, for the placebo group. Poor performance status and liver involvement were associated with a reduced likelihood to respond to treatment. Major toxicities were similar in both groups with no statistically significant difference in the rates of deep vein thrombosis, pulmonary thromboembolus, grade 4 neutropenia, or grade 4 thrombocytopenia. CONCLUSION: These results demonstrate that the addition of high doses of tamoxifen to this chemotherapy regimen does not increase the response rate compared with chemotherapy alone in unselected patients with metastatic melanoma.

Adult↗

PubMed1996

Aging and bone metabolism in African American and Caucasian women.

There is limited information concerning bone mineral density (BMD) and its determinants across a wide spectrum of ages in African American females (AAF). Therefore, we have performed a cross-sectional study of 54 AAF and 39 Caucasian females (CF), aged 20-90 yr, to quantify femoral and lumbar bone mineral density, total body calcium, as well as the potential determinants of bone density. BMD decreased with age in all sites after age 40 yr in both racial groups. Bone density was greater in AAF than in CF, although there was considerable overlap between the two groups. There was no significant difference in the rate of age-related bone loss between the two groups. At the femoral neck, BMD was below the fracture threshold in 28% of the postmenopausal AAF compared to 47% of postmenopausal CF. L1-L4 BMD was below the fracture threshold in 8% of postmenopausal AAF and 11% of postmenopausal CF. Serum-25 hydroxyvitamin D (25OHD) was inversely related to age in both othnic groups and lower (P < 0.05) in premenopausal AAF than CF. Twenty-four percent of the AAF and 22% of the CF had serum 25OHD levels of 8 ng/L or less. Serum PTH was directly related to age (r = 0.43; P = 0.003 in AAF and r = 0.55; P = 0.002 in CF), and 25OHD was inversely related to age (r = -0.43; P = 0.003 in AAF and r = -0.65; P < 0.001 in CF). PTH was higher (P < 0.05) in postmenopausal AAF than in CF. Serum testosterone was greater in AAF than in CF (P < 0.05). Serum estradiol was greater in premenopausal AAF than in CF. Serum dehydroepiandrosterone sulfate was inversely related to age (r = 0.42; P = 0.004 in AAF and r = 0.51; P = 0.005 in CF). Serum osteocalcin was related to age in AAF (r = 0.47; P = 0.001), but not in CF. There was also a trend for an increase in urinary dipyridinoline (expressed per 100 mg urinary creatinine) with age (r = 0.31; P = 0.055 in AAF and r = 0.37; P = 0.066 in CF). Both lean and fat mass were major determinants of femoral neck BMD in AAF. Femoral BMD was directly related to body weight and body mass index in both races. Serum 25OHD and dehydroepiandrosterone sulfate approached statistical significance as independent predictors of femoral BMD in AAF. We conclude that in AAF, 1) bone density is higher than in CF, but there is a significant risk of fracture in a substantial number of subjects on the basis of BMD; 2) there is no difference in rates of age-related bone loss compared to those in CF; 3) both lean and fat mass are significant determinants of bone density; 4) serum estradiol and testosterone were higher than those in CF; and 5) aging is associated with increased bone turnover, 25OHD deficiency, and secondary hyperparathyroidism in both races. The absence of a difference in rates of bone loss between AAF and CF despite higher serum levels of PTH is compatible with the concept of a relative skeletal resistance to PTH in AAF.

Adolescent↗

PubMed1996

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.350.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoralcaudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.

Journal Article↗