Biomedical subjects
Publications and source records attributed to K Lundgren.
Sixteen patients with dementia were studied 4 years after admission to group-living (GL) units, an intermediate level of dementia care. Of eight patients who were still alive, four lived in the GL units and four had been institutionalized. The eight patients who had died had spent 89% of their survival time in GL. Aggression was the most frequent cause of institutionalization.
During the past decade there has been a dramatic increase in the number of children born with prenatal exposure to cocaine. However, there is very little hard data concerning the later development of these children. The purpose of this preliminary study was to compare the language development profiles of 5 children prenatally exposed to cocaine and associated risk factors to the language development profiles of a matched non-exposed control group in terms of analyses of the discourse-pragmatic, semantic, and form components of language. The language evaluation was based on the analysis of a 30-minute language sample. The results suggested differences between the two groups as well as differences within the cocaine-exposed group. The major differences between the two groups were in discourse-pragmatics although less marked differences in syntactic development were also found. The results are discussed in relation to the potential contribution of pertinent medical and environmental risk factors. The study suggests that for children with prenatal exposure to cocaine in combination with multiple associated risk factors, language development may be compromised.
The ethoxyresorufin O-deethylase (EROD) induction of 20 polychlorinated dibenzofurans (PCDFs) was examined in the H4IIE rat hepatoma cell bioassay. The selection of the compounds tested was based on a multivariate chemical characterization laying the groundwork for covering the whole chemical series of PCDFs. The EROD induction potency was found to vary in ED50 values from 25 to 100,000,000 pg/mg, i.e., nearly seven orders of magnitude. The response of the bioassay was calibrated against the 2,3,7,8-tetrachlorodibenzo-p-dioxin, enabling the corresponding toxic equivalency factors (TEFs) to be calculated. In order to establish a quantitative structure-activity relationship (QSAR) for the TEF values, 37 physicochemical descriptor variables were used to chemically characterize the 87 tetra- to octachlorinated PCDFs. Using partial least-squares modeling on a training set of 10 congeners, a QSAR model with sound predictive power was obtained. The QSAR model was validated with a validation set of additional 10 congeners. The predicted TEFs indicate that a large number of congeners are potent EROD inducers.
The effect of UVA radiation (321-400 nm) on UVB photocarcinogenesis was examined in lightly pigmented hairless hr/hr C3H/Tif mice. Five groups of 22 mice were exposed to UVB radiation (281-320 nm) from one Philips 12 tube for 10 min per day and 4 days per week. Four of the groups were simultaneously exposed to UVA from two to six filtered Philips 09 tubes. The daily dose of UVB was 2.0 kJ m-2 in all five groups; the UVA2 (321-340 nm) dose varied from 0.7 to 4.5 kJ m-2 and the UVA1 (341-400 nm) dose from 0.3 to 45.6 kJ m-2. A sixth group was exclusively irradiated with the filtered UVA tubes and served as a control. Skin tumor development was not significantly different for the groups exposed to the UVB source alone or the UVB source in combination with the largest daily UVA dose (0.2 > p > 0.1). Skin tumor development was significantly delayed in the other groups irradiated with the UVB source and the lower doses of UVA (p < 0.001). No tumors were observed in the control group. This study suggests that UVA1 radiation delays UVB-induced skin tumor development. However, the delay cannot be expected to persist when UVA is administered in higher daily doses.
The effect of solar exposure during a one-week sunbathing vacation in May at 29 degrees N latitude was investigated in 22 volunteers. The following end-points were measured before and after the holiday: skin reflectance at 507 nm, transmission of radiation from 289 nm to 448 nm through the epidermis, epidermal thickness, minimal erythema dose (MED), total white cell, neutrophil, lymphocyte, and lymphocyte subpopulation counts in blood, spontaneous DNA synthesis, DNA strand breaks and sister-chromatid exchange in lymphocytes, and the UVC tolerance of lymphocytes. There was a statistically significant decrease in skin reflectance (p < 0.001) and epidermal transmission (p < 0.01) after the holiday, reflecting increased pigmentation and epidermal thickening. There was a statistically significant increase in epidermal thickness (p < 0.001), MED (p < 0.05), spontaneous DNA synthesis (p < 0.01) and DNA strand breaks in lymphocytes (p < 0.02) after the holiday. The other end-points were not significantly changed. We report that changes in skin pigmentation and epidermal thickness occur after one week of UV exposure. It was also observed that a one-week UV exposure increased both spontaneous DNA repair and the amount of DNA strand breaks in the lymphocytes of the volunteers, while no changes in T-cell subsets were detected.
Explore the source record for details and available documents.
A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environmental monitoring of welding fumes and selected metal oxides, biomonitoring of chromium and nickel in serum and urine and mutagenic activity in urine, and evaluation of semen quality were also done. Manual metal arc (MMA) welding and tungsten inert gas (TIG) welding were the dominant welding processes. A higher frequency of chromosomal aberrations, classified as translocations, double minutes, exchanges and rings, was observed in stainless steel welders than in non-welders. SCE was lower in welders working with both MMA and TIG welding than in reference persons. N-Acetoxy-N-acetylaminofluorene (NA-AAF)-induced UDS was lower in 23 never-smoking welders than in 19 unexposed never-smokers. Smoking was a confounding factor resulting in significantly higher CA, SCE, NA-AAF binding to DNA and mutagenic activity in urine. Age was also a confounder: CA, SCE, NA-AAF binding to DNA and UDS increased significantly with age. No significant correlation between SCE and CA or between CA and UDS was found. UDS decreased significantly with increasing lymphocyte count and a higher lymphocyte count was seen in MMA welders than in reference persons and in smokers than in non-smokers. Differences in the composition among lymphocytes in exposed persons compared with non-exposed are suggested. MMA welding gave the highest exposure to chromium, an increased number of chromosomal aberrations and a decrease in SCE when compared with TIG welding. Consequently improvements in the occupational practice of stainless steel welding with MMA is recommended.
Explore the source record for details and available documents.
The carcinogenic effect of three UVA tanning sources was studied in lightly pigmented hairless mice. The three tanning sources (Bellarium-S SA-1-12, Philips TL 09R and Philips TL 10R) have different emission spectra, and emit different amounts of UVB. Radiation from the tanning sources was administered for 20 min/day, 5 day/week in daily doses equivalent to those used in suntan salons. The radiation was given alone or after 12 weeks of exposure to solar-simulated UV radiation (SOLAR UV) (10 min/day, 4 day/week; daily dose, 19.5 kJ/m2 UVA and 3.9 kJ/m2 UVB). Irradiation with Bellarium-S SA-1-12 for 47 weeks and Philips TL 09R for 74 weeks induced skin tumours in 20/20 and 13/20 of the animals, respectively. When irradiation with Bellarium-S SA-1-12 and PHilips TL 09R was administered after 12 weeks of SOLAR-UV exposure, a strong enhancement of SOLAR-UV-induced photocarcinogenesis was observed (p < 0.001). Irradiation with Philips TL 10R was only slightly carcinogenic, and during 85 weeks of irradiation only one skin tumor appeared in a group of 20 mice. However, when irradiation with Philips TL 10R was administered after 12 weeks of exposure to SOLAR UV, an enhancement of SOLAR-UV-induced carcinogenesis was observed (p < 0.001). Our results suggest that the hazards of exposure to commercial tanning devices are increased when they are used after a period of natural sun exposure. Even tanning sources with a low carcinogenic potential are able to increase SOLAR-UV-induced carcinogenesis significantly.
wee1 acts antagonistically to cdc25 in the tyrosine dephosphorylation and activation of cdc2, yet biochemical evidence suggests that wee1 is not required for tyrosine phosphorylation and its role is obscure. We show here that a related 66 kd kinase, called mik1, acts redundantly with wee1 in the negative regulation of cdc2 in S. pombe. A null allele of mik1 has no discernible phenotype, but a mik1 wee1 double mutant is hypermitotically lethal: all normal M phase checkpoints are bypassed, including the requirement for initiation of cell cycle "start," completion of S phase, and function of the cdc25+ mitotic activator. In the absence of mik1 and wee1 activity, cdc2 rapidly loses phosphate on tyrosine, both in strains undergoing mitotic lethality and in those that are viable owing to a compensating mutation within cdc2. The data suggest that mik1 and wee1 act cooperatively on cdc2, either directly as the inhibitory tyrosine kinase or as essential activators of that kinase.
Immunocytochemistry was used to examine MAP5 immunoreactivity in the hippocampal formation obtained postmortem from five elderly, normal individuals, six individuals with Alzheimer's disease (AD), and two "transition" cases that did not have a history of dementia but did exhibit significant AD pathology. In all of the cases examined, axonal staining was restricted to the mossy fibers and their terminal field in CA3 stratum lucidum. In control cases, MAP5 immunoreactivity was observed in the neuronal cytoplasm and the proximal portion of the apical dendrites of pyramidal and granule cells. In both AD and transition cases, increased intensity of immunostaining was observed in CA3 pyramidal, subicular, and dentate gyrus granule cell neurons. Within individual neurons, immunoreactivity filled the neuronal perikarya, including the nuclear region, and the apical dendrite. Punctate staining was observed in neuritic plaques, but neurofibrillary tangles and neuropil threads were not immunostained. The increase and altered distribution of MAP5 immunoreactivity in both vulnerable and nonvulnerable neurons in AD may reflect an aberrant sprouting response. The increased expression of early cytoskeletal proteins may be tolerated in some regions such as CA3, but not in others including CA1 where the increased expression appear to precede aberrant phosphorylation, proteolysis, and incorporation of cytoskeletal proteins into AD pathology. Alternatively, the results could reflect sprouting in response to the neuronal loss and degeneration.
The effect of cisapride on duration of post-operative ileus after surgery was investigated in a randomized, double-blind, placebo-controlled study. Patients undergoing elective upper gastrointestinal (n = 47) or colonic (n = 22) surgery were pre-operatively randomly allocated to treatment with either cisapride 30 mg t.d.s., by rectal administration, or placebo. Treatment started exactly 48 h after surgery if the patient at this time had not passed stool. Time to passage of first stool after surgery was estimated. Mean time to passage of stool was 85 (32) h (s.d.) for cisapride-treated and 91 (43) h for placebo-treated patients. No difference between the treatment groups was noted. Treatment with cisapride did not shorten the duration of postoperative ileus after either upper gastrointestinal or colonic surgery.
A total of 102 children with recurrent otitis media or therapeutic failure after treatment with phenoxymethyl penicillin were entered into a double-blind study with parallel groups, comparing treatment with amoxycillin/clavulanate suspension (Spektramox) for 7 days with amoxycillin suspension (Imacillin) for 10 days. Bacterial and clinical investigations were performed. A total of 91 patients were evaluated for efficacy at the first follow-up visit (10-12 days after start of treatment). Amoxycillin/clavulanate and amoxycillin showed equally high, satisfactory treatment results, i.e. more than a 90% response. Similarly, there was no statistically significant difference between the treatment groups at the second follow-up visit (about 30 days after start of treatment). Bacteriological cultures from the nasopharynx showed equal distribution of Haemophilus influenzae, Branhamella catarrhalis and Streptococcus pneumoniae between the study groups. Elimination of the initially occurring pathogens was equal in the two study groups with the exception of B. catarrhalis which was eliminated to a significantly higher extent with amoxycillin/clavulanate. Both drugs were well tolerated. In patients with recurrent otitis media or therapeutic failure, treatment with amoxycillin/clavulanate for 7 days results in high, satisfactory clinical effects and is comparable to treatment with amoxycillin for 10 days.
The carcinogenic effect of 3 commercially available ultraviolet A (UVA) tanning sources was studied in lightly pigmented hairless mice. The tanning sources (Bellarium-S SA-1-12 and Philips TL 09R and TL 10R) have different emission spectra and emit different quantities of UVB. The tanning sources were administered either alone, or before irradiation with solar-simulated UV (solar UV). All 3 UVA tanning sources were able to induce skin tumors when administered in daily doses resembling those used in tanning salons (20 min/d, 5 d/week). Irradiation with Bellarium-S during 32 weeks induced skin tumors in all mice; a similar response was seen after 66 weeks of irradiation with Philips TL 09R. Irradiation with Philips TL 10R during 98 weeks induced tumors in 6 of 20 mice. Nine groups of 20 mice were pretreated 20 min/d, 5 d/week during 13 weeks with one of the UVA tanning sources. Three groups were irradiated with Bellarium-S, 3 groups with Philips TL 09R and 3 groups with Philips TL 10R in daily doses ranging from 0.2 to 1.8 minimum erythema doses (MED). The highest daily doses were equivalent to the doses received during one session in a commercial solarium. Subsequently all 9 groups were irradiated with 3.1 MED/d solar UV 10 min/d, 4 d/week until all mice had died. Time to first tumor was compared. All groups pretreated with Bellarium-S and Philips TL 09R showed an enhanced tumor development compared with a group irradiated with solar UV only. Pretreatment with Philips TL 10R did not enhance the carcinogenic effect of solar UV.
Explore the source record for details and available documents.
At the ENT clinic in Luanda, Angola, 110 consecutive cases of children with chronic otitis media (COM) were studied to find out some clinical characteristics regarding age of onset and duration of otorrhea as well as the general state of health of the children. Eighty-five percent of the children had had longstanding otorrhea. In 75% of all the cases ear discharge had started during early childhood. It was possible to institute a simple conservative treatment of COM. Fifty percent returned to the clinic for a follow-up. The majority of the children came from families who lived under fairly good social conditions. One-hundred and five children with sensorineural hearing loss consulted the clinic. Many of them had had their hearing loss for several years before coming to the clinic. The etiology was in 39 cases infectious disease, meningitis being the most common one. Seventy-two percent had severe to profound hearing loss. Children with slight to moderate hearing loss rarely appeared at the clinic. Some of the hearing-handicapped children could be sent to a special school for rehabilitation.
Forty-seven patients in psychogeriatric day centre were analysed regarding use of resources, costs and well-being. The level of well-being was based on interviews with staff and relatives and related to the economic outcome--a cost utility analysis. A 6 month period prior to day care was compared with the first 6 months in such care. The use of resources at home increased by 20% while the use of institutional care was reduced by 22%. Fifty-three percent of the patients improved in their well-being after participation in day care. When the cost of utility analysis was applied, the cost for a well-year was 4293 pounds.
Explore the source record for details and available documents.