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Biomedical subjects

L L Hansen

Publications and source records attributed to L L Hansen.

99 records · Page 6Linked to original sources
PubMed1984

Tethered versus loose sows: ethological observations and measures of productivity. I. Ethological observations during pregnancy and farrowing.

Ethological parameters were recorded from sows housed in the same room and allocated to four experimental groups: sows that were tethered during pregnancy as well as from one week before farrowing to 8 weeks after; sows that were tethered during pregnancy but were loose during farrowing and lactation; sows that were loose during pregnancy in social groups of 2-5 animals and tethered during farrowing and lactation, and sows that were loose during pregnancy as in group 3 and also loose during farrowing and lactation. By using a timelapse-film technique it was found that pregnant sows in all groups had a similar diurnal rhythm with peaks around feeding times. The animals lay down for 20 h or more per day, and their activity was reduced due to tethering during the pregnancy period itself and due to preceding periods of tethering during farrowing and lactation. With increasing environmental temperature the loose sows increased the time spent lying on the side at the expense of lying on the belly. The tethered sows, however, showed no such change, but contrary to the loose sows they increased their activity. Observations around feeding time revealed that the tethered sows showed more aggression and fewer non aggressive social elements than the loose sows. Additionally their eating time was longer. Rubbing the neck was less and lying unquietly more frequent in tethered sows. Finally tethering during pregnancy reduced exploration directed towards straw and floor and increased stereotyped bar-biting and chain-nippling. With increasing temperature rubbing behaviour and drinking increased in tethered but not in loose sows. Timelapse-videorecording during the last 48 h prior to- and until the end of farrowing revealed that sows in all groups, no matter whether they were loose or tethered, showed a characteristical increase in nestbuilding activity until about 12-6 h before first piglet was born. Tethering in any period (pregnancy and/or farrowing-lactation) resulted in an increased farrowing time by approximately 100 min.

Animals↗
PubMed1981

Effect of calcium, furosemide and chlorothiazide on net volume reabsorption and basolateral membrane potential of the distal tubule.

In the distal tubule of the isolated kidney of Amphiuma net volume reabsorption (split-oil droplet method) and basolateral membrane potential (psi b) were measured. Luminal perfusion solution could be changed rapidly from 108 mmol . 1-1 NaCl plus 0.1 mmol . 1-1 calcium to solutions containing 103 or 97 mmol . 1-1 NaCl plus 3.6 or plus 7.2 mmol . 1-1 calcium. Furthermore, 10(-4) mol . 1-1 furosemide or chlorothiazide were applied luminally. (1) Addition of 7.2 mmol . 1-1 calcium hyperpolarized psi b from -73.4 mV to -108.3 mV and inhibited net volume reabsorption. (2) Similarly, when furosemide was injected, psi b was hyperpolarized and net volume reabsorption reduced. Application of both high calcium and furosemide further inhibited volume reabsorption. (3) The effects of chlorothiazide were similar to those of furosemide. However, when both high calcium and chlorothiazide were administered psi b and volume reabsorption were almost normalized. (4) The data are consistent with the hypothesis that calcium and the diuretics interfere primarily with chloride uptake across the luminal membrane and thus reduce sodium chloride transport. When chlorothiazide in the presence of high luminal calcium almost normalized chloride transport, it is likely that its effects were by stimulating calcium transport and thus increasing intracellular calcium activity.

Animals↗
PubMed1980

The effects of extracellular potassium, ouabain, and prostaglandins on intracellular potassium activity in sheep cardica Purkinje fibers.

(1) Intracellular K activity (aKi) of sheep heart Purkinje fibers was measured using K-selective microelectrodes (liquid ion exchanger). aKi in the resting state with an extracellular K of 4 mmol . l-1 EK was 112.9 +/- 6.1 mmol . l-1 (n = 47) for a membrane potential (VM) of -73.3 +/- 0.9 mV. VM deviated from the calculated potassium equilibrium potential (EK = -93mV). (2) When extracellular K was decreased to 2 mmol . l-1 or increased to 6 and 10 mmol . l-1 EK changed from -114 to -84 and -73 mV, with little change in aKi. (3) aKi and VM significantly decreased after administration of 10(-6) mol . l-1 ouabain. (4) Prostaglandins (PGI2 10-100 micrograms . l-1 and PGE2 0.01-1 microgram . l-1) decreased aKi without greatly changing VM. The differences between VM and EK became smaller. These effects indicate an increase in K permeability and may explain the antiarrhythmic action of prostaglandins.

Animals↗
PubMedDate not supplied

[Indications for eye examination of HIV patients--screening parameters for cytomegalovirus retinitis].

BACKGROUND: To reduce the burden of frequent visits at the physician we have checked (I) for which ocular manifestations in HIV-infection screening of asymptomatic patients is worthwhile and (II) which parameters may indicate patients at risk for CMV-retinitis. PATIENTS AND METHODS: The clinical data of 215 HIV-infected patients were analyzed retrospectively. Only those ocular manifestations were considered suitable for screening that (a) endanger vision, (b) are treatable, (c) can be diagnosed sufficiently early and (d) are common. Furthermore (1) CDC-stage, (2) CD4+ count, (3) HIV-retinopathy, (4) CMV-uria and (5) CMV-antibodies were checked for their usefulness in indicating patients at risk for CMV-retinitis. RESULTS: Ophthalmological screening of asymptomatic HIV-patients should focus on cytomegalovirus (CMV)-retinitis because early diagnosis of this common blinding disease improves the visual outcome. 85 of 215 HIV-infected patients had a CD4+ count less than 50 cells/microliters 25% of these patients developed CMV-retinitis (21/85). The risk for CMV-retinitis rose to 38% (13/34) when the low CD4+ count was accompanied by CMV-uria. The proportion of patients with CMV-retinitis did not increase when HIV-retinopathy had been diagnosed earlier (12/48 = 25%). CMV-serology and CDC-classification were not helpful in screening for CMV-retinitis. CONCLUSIONS: We recommend the following ophthalmological screening scheme for HIV-patients without ocular symptoms: (1) patients with a CD4+ count < 100 cells/microliters should be checked every third month and (2) those with a CD4+ count < 50 cells/microliters and CMV-uria every sixth week.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Did the spectrum of endophthalmitis change? A study comprising 13 years experience with operative therapy of endophthalmitis.

PURPOSE: The authors wondered whether the spectrum of endophthalmitis and the type of therapy had changed. METHODS: Files of patients who were operated upon for endophthalmitis between 1988 and 2000 were retrospectively analyzed. They were divided into Group 1 (operated upon 1988 to 1994) and Group 2 (1995 to 2000). RESULTS: Group 1 consisted of 83 patients (43.4% female, mean age 63.9 years), Group 2 of 108 (38.9% female, mean age 64.6 years). Bilateral endophthalmitis occurred in 8.4% of Group 1 patients (3.7% of Group 2 patients). Patients in both groups took on average 1.2 drug types against various internal diseases. The mean interval between first symptoms and presentation in the clinic was 45.7 days in Group 1 (19 days in Group 2; difference statistically significant). There were 63% (Group 1) (70% [Group 2]) cases of postoperative endophthalmitis, among them 58% (Group 1) (63% [Group 2]) after cataract extraction, 6% (Group 1) (5% [Group 2]) after glaucoma surgery, 20% (Group 1) (17% [Group 2]) endogenous and 17% (Group 1) (13% [Group 2]) post traumatic. In Group 2 slightly more Gram-negative bacteria were found. As an initial procedure the following were performed: vitrectomy (70% [Group 1], 88% [Group 2]), removal of crystalline lens (11% [Group 1], 10% [Group 2]), removal of pseudophakos (2% [Group 1], 12% [Group 2]), opening of posterior capsule (1% [Group 1], 9% [Group 2]), and anterior chamber irrigation (36% [Group 1], 43% [Group 2]), often combining procedures. There were significantly more vitrectomies and openings of the posterior capsule in Group 2. Neither the spectrum of secondary and tertiary procedures nor the reasons for such surgery differed in both groups. Neither visual acuity at initial presentation (0.1) nor at final follow-up (0.3) differed between the two groups. The rate of enucleation was less in Group 2 (6% versus 11%) although not statistically significantly. CONCLUSIONS: In Group 2 there were slightly more Gram-negative bacteria and the time interval between initial symptoms and presentation in the clinic had decreased. This can be interpreted as an increase in the severity of the endophthalmitis cases. The final visual acuity was identical in both groups, the enucleation rate improved.

Adolescent↗
PubMedDate not supplied

Reduction of retinal exudates in diabetic retinopathy after heparin-induced extracorporal LDL-precipitation (HELP). A case report.

INTRODUCTION: Exudative diabetic retinopathy is difficult to treat. We describe a patient in whom we believe extracorporeal LDL-precipitation (HELP) improved visual acuity. METHODS: HELP is a variant of extracorporeal dialysis which reduces low-density lipoprotein and fibrinogen levels. CASE REPORT: A heavily overweight patient with massive exudative diabetic retinopathy was administered HELP. Four months after starting HELP, and after vitrectomy and panretinal photocoagulation, the massive exudation was drastically lower. Visual acuity improved from 0.03 (0.02) OD (OS) to 0.25 (0.13) OD (OS). DISCUSSION: The role of vitrectomy and panretinal photocoagulation is discussed. HELP seems to be the most probable explanation for our patient's gain in visual acuity.

Chemical Precipitation↗