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Biomedical subjects

N Christensen

Publications and source records attributed to N Christensen.

At least 19 recordsLinked to original sources
PubMed1992

Suicides among Danish patients with cancer: 1971 to 1986.

The risk of suicide or other violent death was assessed among 296,331 patients with cancer in Denmark from 1971 to 1986 by linkage between the National Cancer Registry and mortality files. There were 1,637 violent deaths, of which 568 were suicides. The relative risk (RR) of suicide was significantly increased in the first 2 years after a cancer diagnosis, independent of age at cancer diagnosis. A lower suicide risk was seen after diagnosis of localized cancer (RR = 1.3; 95% confidence intervals [CI]: 1.1 to 1.4), compared with that seen after a nonlocalized cancer (RR = 1.9; 95% CI: 1.5 to 2.4). High risks for suicide were observed for patients of each sex after diagnoses of tumors of the brain and nervous system and with cancer of the lung, stomach, rectum, and kidney; high risks were found among male patients only after a diagnosis of lymphoma or pancreatic cancer. Surprisingly, the risk of suicide has increased significantly in more recent years.

Accidental Falls↗
PubMed1992

Malignant Warthin's tumour: a case study.

Malignant transformation of a benign Warthin's tumour (adenolymphoma) is extremely rare. The light microscopic and ultrastructural features of an adenocarcinoma arising in a Warthin's tumour in the parotid gland are described. Light microscopy demonstrated a transition zone from the benign to the malignant component, and the malignant cells revealed oncocytic features by both light- and electronmicroscopy.

Adenolymphoma↗
PubMed1992

Vegetable oils instead of xylene in tissue processing.

In an effort to improve working conditions in the histopathologic laboratory, we have investigated whether less toxic substances may be substituted for the toxic organic solvent xylene currently in use. Xylene is used in the clearing as well as the deparaffinization process. We have tested whether the substitution of xylene by olive oil and coconut oil leads to any difference in the quality of the histologic sections. Two tissue blocks from each of 232 specimens sent for histopathologic evaluation were subjected to parallel processing in xylene and oil. The specimens represented a broad spectrum of tissue types. All sections were stained with hematoxylin-eosin to permit evaluation of histologic and cytologic details. Furthermore, a range of histochemical and immunohistochemical stainings were applied to a subgroup of tissue sections. The results showed qualitative differences between xylene-processed and oil-processed tissue in only a minority of cases. In no cases were the oil-processed samples considered less suitable for histologic diagnosis. In the histochemical and immunohistochemical stainings, no differences were registered. Although the long-term stability of oil-processed tissue remains to be clarified, we conclude that less toxic vegetable oil may probably be substituted for xylene without losing valuable diagnostic information.

Histological Techniques↗
PubMed1988

Hydrophobic 3.7 kDa surfactant polypeptide: structural characterization of the human and bovine forms.

The human and bovine forms of the hydrophobic 3.7 kDa surfactant polypeptide have been structurally analyzed. The polypeptide is essentially inert to enzymatic proteolysis, and methods for analysis include peptide handling in organic solvents and fragment generation by limited acid hydrolysis. The molecule exhibits N-terminal trimming, and the relative abundance of the different starting positions varies both among species and between adult and fetal forms of the surfactant polypeptide. The bovine major form is one residue shorter than the mature 35-residue human molecule. Comparison of the porcine, human and bovine polypeptides reveals a conserved hydrophobic middle/C-terminal segment and a variable hydrophilic N-terminal part.

Amino Acid Sequence↗
PubMed1987

Changing clinical spectrum of splenic abscess. A multicenter study and review of the literature.

The changing demographics of splenic abscess in regard to predisposition, clinical setting, diagnosis, bacteriologic findings, and treatment have been presented based on 19 patients from five institutions and 170 patients reported in the literature since 1978. These data, in turn, have been compared with a previously published retrospective review of the world literature from 1900 to 1977. It has become clear that since 1978, splenic abscess is diagnosed earlier in its presentation due to the widespread use of improved imaging techniques, immunocompromised patients comprise a much larger proportion of patients (24 percent) than previously due to increasing use of steroids and chemotherapeutic agents, and the diagnosis of fungal splenic abscess, almost unheard of before 1978, has increased to 26 percent of patients. The diagnostic sensitivity of computerized tomography (96 percent) has clearly been shown to be superior to ultrasonography, and gallium, indium, and technetium-99m liver and spleen scanning. The diagnosis of splenic abscess, however, is still often not considered due to its rarity and the presence of predisposing conditions which obscure its clinical presentation. Untreated splenic abscess is still fatal, and although splenectomy is the mainstay of treatment, it appears that antifungal treatment without splenectomy can be recommended for patients with disseminated fungal disease as long as bacterial abscess has been ruled out by invasive culture techniques. Scattered reports of percutaneous drainage exist and are increasing in the literature, although the results are as yet inconclusive. Eventual recovery depends on early diagnosis and successful treatment of the underlying condition.

Abscess↗
PubMed1987

Lipofuscinosis of the human uterus.

A case of uterine lipofuscinosis in a patient with Friedreich's ataxia is described. Ultrastructural investigation confirmed the mitochondrial origin of the lipofuscin. Clinically, the patient suffered from brown bowel syndrome. Both the brown bowel syndrome and the uterine lipofuscinosis in the present case may be related to Friedreich's ataxia.

Adult↗
PubMed1986

Pathogenicity and persistence of pleural effusion disease virus isolates in rabbits.

Nine isolates of pleural effusion disease agent or virus (PEDV) from treponema-infected rabbits in various countries were examined for pathogenicity and persistence in rabbits. The isolates showed a wide range of pathogenicity and were categorized into three groups according to the severity of the acute infection. Group 1 comprised isolates causing more than 50% mortality, group 2 isolates causing mortality below 50%, while group 3 comprised isolates causing almost subclinical infections. The range between group 1 and group 3 was similar to that observed with virulent and avirulent progeny of the original PEDV isolate. Infection by each of the nine isolates resulted in a chronic low level viraemia which persisted for up to 2 years or more. Viral progeny of pathogenic isolates obtained in serum after the 2nd month of infection failed to induce clinical disease on rabbit inoculation. The chronic, subclinical infection was associated with a moderate, continued increase in serum IgG, but circulating immune complexes could not be demonstrated. Two years after infection slight histopathological changes were present in lymph nodes, spleen, liver, heart and lung. Evidence of immune complex disease could not be demonstrated.

Animals↗
PubMed1985

A double-blind, crossover study of a sustained-release tablet of ketoprofen and normal ketoprofen capsules in the treatment of patients with osteoarthritis.

A double-blind, crossover study was carried out to assess the efficacy and tolerance of a sustained-release tablet formulation of ketoprofen given as a single daily 200 mg dose compared with 2 X 50 mg normal formulation capsules of ketoprofen twice daily. Eighty-four patients with osteoarthritis of the hip and/or knee were admitted and received treatment for periods of 3 weeks, preceded by a 1-week placebo wash-out period, with each of the two formulations, in random order. Patients were seen after each study period and clinical objective and subjective assessments made of signs and symptoms of the disease, consumption of rescue analgesic and unwanted effects. Forty-eight of the patients continued, mainly on the sustained-release formulation, in an open long-term tolerance study lasting 3 months. The results were analyzed for 68 patients who completed the double-blind phase and for 33 who completed the open phase of the study. The patients who were withdrawn did so mainly for non-drug related reasons; 19 patients did so because of gastric disorders during the first phase. The incidence of side-effects was low and similar in frequency and nature with both formulations; those that were reported were mild and principally gastro-intestinal. Both active treatment periods afforded similar symptomatic relief and were preferred to placebo by all but 2 patients. No significant differences were found between active treatments, although there was a trend in favour of the sustained-release formulation for most of the parameters studied as there was in patient preference.

Aged↗
PubMed1979

Evaluation and treatment of penetrating cervical injuries.

Because the serious nature of penetrating cervical injuries may not be readily apparent on initial evaluation, and since delay in treatment can result in serious complications, a systematic method of evaluation and routine exploration has been employed in treating these injuries. One hundred eighty-nine patients, 49 with gunshot wounds and 140 with stab wounds, were treated in this series. Arteriography was performed in 62 patients (33%) to detect vascular injuries and to aid in the planning of the operative approach in patients with high or low neck wounds. Arteriography was 98% accurate and changed the operative approach in 29% of the positive studies. Of the 154 explorations 72 were positive (47%). There were no deaths and only four complications in the group with negative explorations. The mortality rate for the series was 2.6%. We believe that angiography in selected patients and routine exploration of wounds penetrating the platysma can minimize morbidity and mortality in these injuries.

Adolescent↗
PubMed1979

Teratogenicity of intrauterine copper wire in mice. A histopathological study.

Immediately after the implantation of the fertilized ovum, on the 6th day of pregnancy a copperwire was placed in the right hand uterine section on pregnant C3H mice. The left section was similarly surgically traumatized in order to serve as a control. The mice were killed with chloroform on the 19th day of pregnancy and by means of a special histological screening technique the fetuses were examined with special reference to growth reduction, intrauterine fetal death and microscopic malformations. Differences in intrauterine fetal death were shown not to exist, nor was there any significant growth retardation in the copperwire containing uterine section. Certain microscopic defects were found with slightly increased incidence in the copper containing section, but the differences were not statistically significant.

Animals↗
PubMed1979

Experimental endocarditis in rabbits. 3. Significance of the proteolytic capacity of the infecting strains of Streptococcus faecalis.

Insertion of a polyethylene catheter into the left ventricle of the heart was used for regular establishment of sterile endocarditis, and bacterial endocarditis was established by injection of approximately 10(8) Streptococcus faecalis into the blood stream at the same time as removal of the catheter which had been in place for 3 days. 100 out of 102 rabbits died spontaneously of bacterial endocarditis. Evidence is produced that the host-parasite interaction is influenced by the proteolytic property of S. faecalis in this experimental model. Two distinct types of clinical course are described: 1) A predominantly acute and damaging illness, characterized by a high level of bacteraemia, small amounts of soft, friable vegetations in the left side of the heart, high frequency of kidney infarcts and shorter survival time in rabbits infected with proteolytic strains. 2) A relatively subacute illness, characterized by a lower level of bacteraemia, large, hard, non-friable vegetations on the aortic valves, less pronounced destructive changes in the substance of valve leaflets, relatively lower frequency of kidney infarcts and longer survival time in rabbits infected with non-proteolytic strains. The results suggest that proteolytic strains of S. faecalis cause partial dissolution of the vegetations resulting in a more severe clinical picture.

Animals↗
PubMed1978

Pleural effusion disease in rabbits. Histopathological observations.

Pleural effusion disease (PED) is a generalized infection of laboratory rabbits caused by an unidentified agent, believed to be a virus. The histopathological response of 17 rabbits infected experimentally with this agent was studied. The light microscopical changes were minimal and the most consistent findings were alterations of the lymphoid tissue. Fatal infections were characterized by a uniform reduction of the splenic white pulp, focal degenerative changes of the thymus and lymph nodes and probably slight proliferative changes of the kidney glomeruli. In surviving animals there were transient myocardial and hepatic lesions and, after clinical recovery, proliferative changes in spleen, lymph nodes, interstitial lung tissue and probably kidney glomeruli. The results do not permit any conclusions to be drawn regarding the aetiology or the pathogenesis of PED infection.

Animals↗
PubMed1978

Experimental endocarditis in rabbits. I. Technique and spontaneous course of non-bacterial thrombotic endocarditis.

Insertion of a polyethylene catheter into the heart was used for regular establishment of sterile endocarditis in 52 rabbits. The catheter was inserted with the aid of guide wire, and distance marking on the catheter was used to obtain precise positioning, so that the catheter was retained with the curved distal end inside the left ventricle of the heart. The results showed that the catheterization procedure could be carried out with a high degree of accuracy. Uniform localization of the vegetations was obtained, these reaching a suitable size of development in all rabbits after insertion of the catheter for 3 days. Histological examination of the sterile vegetation showed that catheter withdrawal at this time would still permit the regular development of an infection. After withdrawal of the catheter, the sterile vegetations rapidly decreased in size and disappeared almost completely by 10 days. Sterile endocarditis in rabbits induced by a catheter for a period of 3 days proved to be a harmless and self-limiting disease. The model presented seems to be suitable for futher investigations on experimental bacterial endocarditis.

Animals↗
PubMed1978

Experimental endocarditis in rabbits. 2. Course of untreated Streptococcus faecalis infection.

Insertion of a polyethylene catheter in the left side of the heart was used to induce sterile endocarditis in 34 rabbits. Bacterial endocarditis was established by injection of approximately 10(8) Streptococcus faecalis into the blood stream simultaneous with the removal of the catheter which had been in place for 3 days. The course of the bacterial endocarditis was examined by autopsy of rabbits sacrificed at regular intervals after the infection. The results showed that the presence of the catheter was not essential for the induction or maintenance of the infection. Growth of the bacteria took place in the preformed vegetations in the aorta, on the aortic valves and in the left ventricle. However, increases in the size of the vegetations, a high density of bacteria in the vegetations and secondary spreading were found only on the aortic valves. The extracardial manifestations of left-sided S. faecalis endocarditis included constant bacteriaemia, a high frequency of septic kidney infarcts and enlargement of the spleen. This form of experimentally provoked bacterial endocarditis in rabbits provides a good imitation of human subacute endocarditis, and would thus seem to be suitable for further study of the pathophysiology of endocarditis and evaluation of the effect of treatment with antibiotics.

Animals↗