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Biomedical subjects

L Dreyer

Publications and source records attributed to L Dreyer.

At least 37 records · Page 2Linked to original sources
PubMed1997

Avoidable cancers in the Nordic countries. Radiation.

Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120 cancers at various sites. For all types of ionizing radiation, the annual total will be 4420 cancer cases, or 3.9% of all cancers arising in the Nordic populations, with 3.4% in men and 4.4% in women.

Female↗
PubMed1997

Avoidable cancers in the Nordic countries. Diet, obesity and low physical activity.

In the early 1980s, Doll and Peto estimated that about 35% of all deaths from cancer in the United States were attributable to dietary factors, with a margin of uncertainty ranging from 10 to 70%. Since then, several dietary factors, e.g. fat and meat, have been suggested to increase the risk for cancer, while other factors, e.g. fibre, fruit and vegetables, have been suggested to decrease the risk. The case-control and cohort studies have, however, given ambiguous results, and the overall evidence is far from conclusive. The major findings on dietary factors that increase risk have been reported from case-control studies, but have not been confirmed in large population-based cohort studies. Although the research in this area indicates that diet is important in cancer prevention, current knowledge does not allow reliable estimates of the numbers and proportions of cancers that could be avoided through well-described modifications of dietary habits. During the last 10 years, low physical activity has been pinpointed as a risk factor for cancers at various sites, especially the colon; however, the causal mechanism is still unknown. Obesity, defined as a body mass index of 30 or more, is consistently associated with endometrial and gall-bladder cancers in women and renal-cell cancer in both men and women. As the prevalence of obesity was between 5 and almost 20% in the Nordic populations in 1995, 625 cancer cases (310 endometrial cancers, 270 renal-cell cancers in men and women and 45 gall-bladder and bile-duct cancers among women) can be predicted in the Nordic countries around the year 2000 to be caused by obesity. This implies that about 1% of all cancers in Nordic women and less than 1% of those in Nordic men could be avoided around the year 2000 if a healthy body weight could be maintained by all inhabitants.

Diet↗
PubMed1997

Avoidable cancers in the Nordic countries. Exogenous hormones.

The well-described influence of several aspects of reproductive life on the risk for cancer in the reproductive organs has raised concern regarding the safety of exogenous hormones, particularly since sex hormones have become one of the most widely used drugs among women in the western world. The major areas of application include oral contraception and hormone replacement therapy in women with menopausal symptoms. Since the introduction of oral contraceptives onto the Nordic market in the late 1960s, the number of users has grown steadily, to reach proportions of long-term users among women aged 15-45 years in 1985 ranging between 6% (Norway) and 19% (Sweden) and proportions of current users in 1994 ranging between 20% (Norway) and 28% (Sweden). Such data on the current and long-term use of oral contraceptives by the female populations, linked with relative estimates of adverse (cancers of the breast and uterine cervix) and beneficial effects (protection against cancers of the ovary and endometrium), indicate that 95 cases of breast cancer and 40 of cervical cancer will be caused by oral contraceptives annually around 2000 in the Nordic countries, which corresponds to 0.6% of all breast cancers and approximately 3% of all cervical cancers. The beneficial effects include an annual prevention around the year 2000 of approximately 350 cases of ovarian cancer and a similar number of endometrial cancer, for a total about 700 cancer cases annually. The prevalence of long-term users (> or = 5 years) of hormone replacement therapy among Nordic women aged 40-69 in 1995 was estimated to be 10-11%, which on the basis of an associated relative risk for breast cancer ranging from 1.2-1.5 suggests than an annual total of 260 cases of breast cancer could be avoided in the Nordic countries around the year 2000 if hormone replacement therapy were eliminated. This corresponds to 1.8% of all notified cases of breast cancer among women in these countries.

Contraceptives, Oral↗
PubMed1996

A complication of mesenteric lymphangioma: case report and brief review of literature.

Mesenteric lymphangioma (ML) has only rarely been reported in the literature. These cases are rare enough to arouse interest when encountered. Usually, the cases are asymptomatic but may present with acute or chronic intestinal obstruction. We report an additional case of ML associated with intermittent intestinal volvulus in a 5 years old boy.

Child, Preschool↗
PubMed1994

Bilateral large-cell calcifying Sertoli cell tumor of the testes with Peutz-Jeghers syndrome: a case report.

A 13-year-old boy with Peutz-Jeghers syndrome (PJs), gynecomastia, and bilateral multifocal testicular tumors is described. Histology of the testicular tissue disclosed large-cell calcifying Sertoli cell tumors. Females with PJs are known to be at increased risk of developing gonadal tumors. This case and a review of other reported cases suggest that males with PJs are also at risk for developing gonadal tumors.

Adolescent↗
PubMed1993

Seborrheic keratoses of black patients with epidermodysplasia verruciformis contain human papillomavirus DNA.

Epidermodysplasia verruciformis (EV) is a rare disease characterized by a generalized cutaneous infection with human papillomaviruses (HPVs) and a propensity for transformation of the lesions to squamous cell carcinomas on sun-exposed areas of the skin. Black-skinned patients with EV have a much lower incidence of skin cancer. Nine of 32 black African patients with EV presented deeply pigmented, flat or slightly raised lesions, located mostly in sun-exposed areas, that clinically had been diagnosed as seborrheic keratoses. Seborrheic keratoses are otherwise very rare in black Africans. Histology of these lesions disclosed seborrheic keratoses, lesions with seborrheic keratosis, and EV changes in the same biopsy specimens and seborrheic keratoses with features of bowenoid dysplasia. Reverse blot hybridization indicated the presence of DNA related to the HPV-5 group of papillomaviruses in seborrheic keratoses in three patients. Subsequent Southern blot analysis revealed a DNA that was related but not identical to any of the papillomaviruses in this HPV-5 group. The fourth lesion studied a few years earlier contained HPV-5c. The question arises whether a different type of HPV is responsible for development of these tumors in black patients with EV.

Adult↗
PubMed1993

Epidermodysplasia verruciformis and malignant thymoma.

We describe a patient with a long history of skin lesions clinically and histologically consistent with epidermodysplasia verruciformis (EV) who developed malignant thymoma. HPV-9DNA was found in the macular lesion and HPV-4DNA and HPV-9DNA in the coexistent common warts. Thrombocytopenia and hypogammaglobulinaemia preceded the diagnosis of thymoma. Our patient seems to represent an example of an EV-like syndrome in immunodeficiency.

Adult↗
PubMed1993

Neuroma of the vulva. A case report.

Even in the definitive textbook on vulvar conditions edited by Ridley no description of neuroma of the vulva exists, although neural tumors and neurofibroma are considered. The medical literature covering the past 25 years records only one case of terminal fiber neuroma in an episiotomy scar and one neuroma of the clitoris. The latter occurred in a patient with neurofibromatosis. This report documents a symptomatic neuroma of the labia minora considered to be the result of a vulval injury. It is postulated that dyspareunia related to episiotomy may be associated with disorganized proliferation of proximal nerve stumps. Because of the rarity and lack of expertise on management of vulval neuroma, we suggest that the International Society for the Study of Vulvar Disease (ISSVD) further investigate this condition.

Adult↗
PubMed1992

Encephalitis and chorioretinitis associated with neurotropic African horsesickness virus infection in laboratory workers. Part IV. Experimental infection of the vervet monkey (Cercopithecus pygerythrus).

Neurotropic vaccine strains of African horsesickness (AHS) virus types 1 and 6 were implicated as the possible aetiological agents in 4 cases of encephalitis and uveochorioretinitis in laboratory workers accidentally exposed to the freeze-dried vaccine preparations of the virus. To date, AHS virus has not been known to infect man. To ascertain whether or not primates were susceptible to infection with AHS virus, vervet monkeys (Cercopithecus pygerythrus) were inoculated, either transnasally or intraconjunctivally, with vaccine strains of AHS virus types 1 and 6. The course of infection was monitored using parameters such as behavioural changes, febrile reaction, cerebrospinal fluid pleocytosis, serology, magnetic resonance imaging and autopsy. Encephalitis, manifested by varying degrees of fever, behavioural changes and pleocytosis, but no chorioretinitis was detected in all 6 transnasally infected monkeys. This was confirmed by autopsy, where a meningo-encephalitis affecting the medial temporal lobe but no lesions in the eyes was demonstrated. Neither virus appeared to infect the animals after intraconjunctival inoculation. These findings support the theory that the patients were infected by the inhalation of freeze-dried vaccine preparations. The pathogenesis of the eye lesions, however, remains uncertain.

African Horse Sickness↗
PubMed1988

A progressive radiorenographic (99mTc-DTPA) presentation of surgically induced renal vein hypertension in baboons.

A 99mTc-DTPA radiorenographic study, supported by excretory urography, blood chemistry and eventually histology was performed on 8 chacma baboons (Papio ursinus) after surgical induction of unilateral renal vein hypertension. Frequent sequential repeat renograms during 6 post-operative months detected fluctuating renal behaviour but did not reveal typical course of the disease. Neither did any one of the radiorenographic parameters (TP, T1/2, FF, relative clearances and perfusion) prove to be more sensitive than the others in detecting abnormalities. Initial microscopic or macroscopic haematuria and proteinuria in general eventually cleared up. Light microscopy demonstrated only mild abnormalities. The effects of venous occlusion of the kidney and the prognosis seemed to be variable as was reflected by radiorenography.

Animals↗
PubMed1986

Myxoid liposarcoma of the right atrium. A case report.

A case of primary liposarcoma of the right atrium is presented. Liposarcomas of the heart are extremely uncommon, only 3 previous cases having been reported in the English-language literature. The tumour must be differentiated from other polypoid cardiac tumours, particularly cardiac myxomas.

Aged↗
PubMed1985

Successive urinary papillomavirus excretion, condylomata acuminata and urogenital epithelial malignant disease after renal transplantation.

Of 3 renal allograft recipients who were found to excrete papillomavirus in the urine, 1 has since developed a condyloma, 1 a condyloma and a keratinizing squamous carcinoma and 1 a transitional cell carcinoma. Peroxidase-antiperoxidase staining has confirmed the presence of papillomavirus antigen in the condylomas. The significance of these findings is discussed.

Adult↗
PubMed1984

Studies on sporotrichosis. Pathogenicity and morphogenesis in the Transvaal strains of Sporothrix schenckii.

In the Transvaal, two epidemiologic patterns of Sporothrix infection occur in man. Evidence gathered from nature, the clinic and the laboratory suggests that these patterns are not the result of either a fixed strain specificity or a random mutation. The differences represent a developmental trend, determined by environmental factors, which gradually transform the wild strains of Sporothrix schenckii into variants resembling the earlier descriptions of Sporothrix beurmannii. This change, moreover, is regular and predictable.

Aged↗
PubMed1984

The myth of high mortality rates due to ischaemic heart disease in white South Africans.

It has often been said that when compared with Whites in other countries South African Whites have an extremely high mortality rate from ischaemic heart disease (IHD), the so-called disease of affluence. This conclusion may arise from a misinterpretation of the mortality statistics of the South African population. The apparent misinterpretation arises from the comparison of the mortality rates for South African Whites (a predominantly privileged and affluent class) with those for the total populations of other countries, which include the labourer classes (in which IHD is less prevalent and which are predominantly Black in South Africa). The argument that socio-economic class must be controlled for in such calculations is demonstrated by a comparison of the occupational structures of the four South African race groups. When the statistics are recalculated to encompass the other groups with a view to including the manual labourer class, there is evidence that South Africa has a low to average incidence of IHD. It is acknowledged, however, that even this may not be an ideal method. Possible influencing factors, in this case socio-economic status, must be controlled for when statistical comparisons of large populations are made.

Adult↗
PubMed1984

The frequency of hepatitis B surface antigen in membranous nephropathy in black and white South Africans.

A series of 244 renal biopsy specimens obtained from patients with glomerulonephritis included 21 from patients with membranous nephropathy (MN). Of these patients 14 (10,7%) were Black, 1 was Indian and 6 were White (5,5%). It is suggested that the high frequency of MN in Black patients may be associated with the high carrier rate (7 - 10%) of hepatitis B virus (HBV) in the Black population. Twenty of the 21 renal specimens were investigated for deposits of hepatitis B surface antigen (HBsAg) using the peroxidase-antiperoxidase method. HBsAg deposits were found in 13 of the specimens obtained from Black patients, in the specimen obtained from the Indian patient and in 1 of the 6 specimens obtained from White patients. HBV appears to be an important aetiological factor in MN in Black South African patients.

Adolescent↗