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Biomedical subjects

H Hammar

Publications and source records attributed to H Hammar.

At least 55 records · Page 3Linked to original sources
PubMed1980

An improved quantitative method for the study of fibrinolysis in the skin as exemplified in patients with leukocytoclastic vasculitis and erysipelas.

The activity of plasminogen activator has been measured in tissue sections with the aid of a modified Todd technique. Frozen skin biopsies were sectioned and the tissue covered with fibrin-plasminogen film. After incubation at 37 degrees C fibrinolysis was studied for a period of 30 min and was graded into six exponentially increasing steps. During this period, grades were linear with the llogarithm of time of incubation. The rate of fibrinolysis is a measure of the activity of the plasminogen activator and is expressed by the slope of the linear regression of grades versus the ogarithm of time; the value of the slope is proportional to the common logarithm of the activity of the plasminogen activator present in the section. Using urokinase as a specific plasminogen activator, the same linear expression was shown with time, indicating the validity of our grading and experimental system. Eleven healthy subjects served as controls to 6 patients with leukocytoclastic vasculitis and 4 patients with erysipelas and 4 with necrotizing fascilitis. The controls showed values similar to the non-involved skin in the patients. The activity was higher in the arm than in the thigh sites. The activity in the thighs was lower in women than in men. A decrease in the plasminogen activator activity was found in the three disorders.

Adult↗
PubMed1979

The measurement of coenzyme A and a coenzyme A-dependent enzyme. In microdissected epidermal material using coupled enzyme and bioluminescent reactions.

A sensitive micromethod for the determination of Coenzyme A and its esters down to about 0.2 pmol in a volume of 10 microliters and of the activity of citrate synthase is outlined. Epidermal material from healthy and psoriatic skin was utilized in microgram quantity as tissue source. The assay utilizes the ketoglutarate dehydrogenase reaction to yield NADH on addition of free Coenzyme A and the subsequent measurement of NADH by a bioluminescent reaction with Acromobacter fischerii. The total Coenzyme A content in six healthy subjects measured in stratum Malpighii was 1.58 +/- 0.19 mmol per kg dry weight. In six psoriatic patients non-involved and involved epidermis contained 1.51 +/- 0.27 and 1.50 +/- 0.25 mmol/kg, respectively. Long-chain acyl-Coenzyme A comprised about 20% in lesion-free skin and 60% of total content in the involved psoriatic epidermis. The activity of citrate synthase in basal layers of healthy epidermis was 0.30 +/- 0.04 mkat/kg dry weight.

Animals↗
PubMed1978

Measurement of the horny layer turnover after staining with dansyl chloride: description of a new method.

A simple non-radioactive technique is described. The corneal layers were stained with 5% dansyl chloride ointment during 24-48 h of occlusion. The number of newly formed corneal layers were counted on sections from punch biopsies obtained at various intervals after the staining. The rate of formation is given as layers formed per 24 hours. The technique makes it possible to detect an increase in the turnover rate when it is more than 15-32% above normal. The biological material can also be utilized for comparative studies utilizing biochemical and histological methods. The average rate of formation was 1.15+-0.09 (S.E.M.) layers per 24 hours in a group of 10 subjects.

Adult↗
PubMed1977

Erysipelas and necrotizing fasciitis.

The clinical course of necrotizing fasciitis in 8 patients is compared with observations on 22 other patients with erysipelas. In necrotizing fasciitis the early erythematous areas turn into a dusky blue colour with later vesiculation and formation of bullae. An important finding is a non-pitting oedema extending outside the erythematous patches. The disease often progresses and involves further skin areas proximal to the initial ones. Gangrene tends to follow in multiple sites after the 1st week of illness. Group A streptococci in conjunction with widespread thrombosis and vascular necrosis of the involved skin are two major factors in the pathogenesis of the gangrene. Early debridement and excision of necrotic tissue in combination with large doses of penicillin and cloxacillin are confirmed as mandatory to remove toxaemia and inhibit further necrosis of the skin. In 3 of the 8 patients with necrotizing fasciitis the syndrome of disseminated intravascular coagulation complicated the course of the disease. A promising therapeutic result was seen in 2 further patients exhibiting alarming signs and symptoms of early necrotizing fasciitis; the combination of heparin, given intravenously in therapeutic doses guided by activated partial thromboplastin time studies, and of systemic antibiotics alleviated the symptoms, which vanished within 10 days of the start of treatment.

Adolescent↗
PubMed1977

Chemiluminescence microanalysis of substrates and enzymes.

Extracts from bioluminescent organisms are increasingly used for analysis of small amounts of substrates and enzymes. The light emission is in some organisms related to the conversion of substrates and cofactors of central metabolic importance. Extracts from such organisms are particularly valuable for analytical applications. This is quite obvious in the firefly where the energy, required for light production, is derived from ATP and in a couple of strains of luminescent bacteria where reduced pyridine nucleotides through reduction of flavine mononucleotide is utilized in the light reaction. It deserved to be noted that many biochemical reactions can be coupled more or less directly to the conversion of ATP, NAD(H), NADP(H) and FMN(H), thus providing the basis for a great variety of analyses. Special kinds of bioluminescent reactions are also of considerable interest, as for instance the relationship between "active sulphate" and PAP, which participate in the formation of light in the sea pansy (Renilla reniformis). High sensitivities are often reached in chemiluminescence analysis making the technique suitable for samples composed of a small number of cells. How bioluminescence has been employed in these kinds of microanalyses is examplified in studies of nucleotides, metabolites and enzymes with low activities.

Adenosine Triphosphate↗
PubMed1977

Provocation with cow's milk and cereals in atopic dermatitis.

Oral provocation test with cow's milk and cereals were performed in 81 children with atopic dermatitis, all below 5 years of age. In 15 of the children exacerbation of the dermatitis occurred on the second or third day after initiation of the tests. These patients, whose mean age was 13 months, underwent repeated provocation during the ensuring 18 months. Eleven children lost their sensitivity to the offending foods and 2 children became more tolerant during this period. Initial levels of serum IgE and specific reagins against the foods tested did not distinguish those patients who were positive to the provocation tests. In this group, however, reagins against egg white were significantly increased. The specific serum reagins were unaltered or increased in the majority of cases during the period of study. The radioallergosorbent test (RAST) was found of limited value as a screening tool in patients with atopic dermatitis in whom exacerbation of the condition appears to be caused by food sensitivity.

Allergens↗
PubMed1977

Annular erythemas in infants associated with autoimmune disorders in their mothers. Report on three cases.

Three infant boys with a centrifugal annular erythema mainly consistent with erythema annulare centrifugum, developing a few weeks after birth, are described. The lesions disappeared before the age of 6 months, without atrophy, and during this period the infants were otherwise healthy. This group is considered to belong to one of three types of reactivity in infants associated with or expressed as a connective tissue disease, especially lupus erythematosus, in the mother and child or in either. In type 1, signs and symptoms of systemic lupus erythematosus are or will be present in the mother and the child displays discoid lupus erythematosus lesions at birth or soon after. In type 2, the mother has the same signs and symptoms as in type 1 but the child develops a centrifugal annular erythema 3-6 weeks after birth. In type 3, discoid lupus erythematosus is present at an early stage in the infant, while the mother is healthy. This type may represent an early onset of lupus erythematosus in the infants.

Adult↗
PubMed1976

A case report including EM and DNA repair investigations in a dermatosis associated with multiple skin cancers: epidermodysplasia verruciformis.

This report describes the clinical, histological and electron microscopic observations in a 51-year-old male with epidermodysplasia veruciformis (EV). Cells with early signs of malignant transformation were found closely connected with virus infected epidermal regions. Skin cancers appeared initially on sun-exposed areas, such as the face and ear lobes. The UV-induced DNA repair synthesis was therefore studied, utilizing peripheral leukocytes. The patient had 40% lower UV-induced DNA repair synthesis than the mean of nine healthy subjects of the same age. These results suggest that a decrease in UV-induced DNA repair synthesis in combination with a possibly oncogenic viral infection may enhance the disposition for somatic mutations and malignant transformation in patients with EV.

DNA Repair↗
PubMed1976

Studies on the carbohydrate metabolism in psoriatic epidermis.

Enzymic activities and cofactor levels in the epidermis are reviewed with special regard to psoriasis and the papulosquamous disorders lichen simplex and lichen planus. The metabolism of nicotinamide adenine dinucleotide phosphate and its dependent pathways seems to deviate in psoriasis from that in the contrasted dermatoses, in normal skin in health and in skin during the process of wound healing. The mitochondrial function also differs between psoriatic and normal skin. In some conditions in psoriasis this function cannot be seen to deviate from normality, however. The regulation and control of mitochondrial function in psoriasis might be another area in which future investigations may yield significant information on the pathophysiology in this skin disease.

Adenosine Triphosphate↗
PubMed1975

Epidermal nicotinamide adenine dinucleotides in psoriasis and neurodermatitis (lichen simplex hypertrophicus).

Epidermal nicotinamide adenine dinucleotides were measured in subcorneal and basal epidermal layers in patients with psoriasis and neurodermatitis and in healthy controls. Lowry's microtechniques utilizing enzymatic cycling were used. The total NAD content in these groups was except for the involved psoriatic skin about 1.1 mmoles/kg dry weight. Between 40 and 50% of this content consisted of the reduced form. In the involved psoriatic skin the total NAD content was increased to 1.5 mmoles/kg, this increase being mainly due to a rise in NAD+. There was no difference in NAD content between epidermal layers in the various groups studied. The total NADP content was near 0.15 mmoles/kg in healthy controls and in patients with neurodermatitis. The subcorneal layers contained 10% more of the dinucleotide than the basal layers, but in the two layers the reduced form amounted to about 80% of the total. In both non-involved and involved skin of the psoriatic patients the total NADP content was significantly increased above the control level, by up to 20% in the former and up to 65% in the latter. In the two layers studied the NADP+ content was increased by about 75% in both non-involved and involved areas. In contrast, the NADPH content rose only in the basal layers of the lesion, by 55%. The increased levels of NADP+ and NADPH found in psoriasis might suggest an accelerated or differently conducted NADPH dependent biosynthesis in this disease.

Adolescent↗
PubMed1975

Epidermal nicotinamide adenine dinucleotides in psoriasis during treatment with dithranol.

Epidermal nicotinamide adenine dinucleotides were measured in subcorneal and basal epidermal layers in patients with psoriasis and in healthy controls during a 2-week period in which they were treated once a day with 0.15% dithranol in white petrolatum. Lowry's microtechniques utilizing enzymatic cycling were used. In the controls the total NAD contents decreased 25% during the treatment period. The total NADP content did not change, nor did the proportions of NADH and NADPH. In the psoriatic patients effects of the treatment were seen only in the epidermis of the lesions. Both the total NAD and NADP displayed an initial increase on the second day, followed by a steady decrease to the levels found in the non-involved skin. During the first week of treatment parakeratosis was still evident in the lesions. In spite of variation in the total NAD contents during this period, a significant reduction of the percentage of NADH was found. Concomitant with the appearance of an orthokeratotic horny layer, both NAD+ and NADH returned to normal. The percentage contribution of NADPH did not change during these events.

Adolescent↗
PubMed1975

Epidermal activity of NAD-dependent isocitrate dehydrogenase in psoriasis during treatment with dithranol.

The activity of ICDH(NAD) was measured in subcorneal and basal epidermal layers in 8 patients with psoriasis and in 7 healthy controls treated once a day with 0.15% dithranol in white petrolatum for 2 weeks. Skin biopsies were taken before and on days 2, 6, and 14 of the treatment. Lowry's microtechniques were used in conjunction with a bioluminescent system (bacterial luciferase) for enzymatic assays. The enzymic activity could be related to the type of keratinization present in the stratum corneum overlying the epidermal areas under study. In orthokeratotic areas from the controls, in noninvolved, and in treated involved skin the activity was low. In parakeratotic areas, as found in treated noninvolved and in involved psoriatic skin, the enzymic activity was increased to a level at least twice that found in orthokeratosis. Since ICDH(NAD) activity reflects an aspect of mitochondrial function, the results suggest that mitochondrial activity may be important in control of keratinization.

Adolescent↗
PubMed1975

Studies on the energy metabolism in lichen planus.

Various epidermal enzymes and cofactors were measured in patients with lichen planus and in healthy controls with the aid of Lowry's microtechniques, including enzymatic cycling. The steady-state levels of the nicotinamide adenine dinucleotides NAD and NADP were decreased and this was evident even in areas still free from lesions. The oxidized and reduced portions of NAD were altered indicating changed equilibria of NAD dependent dehydrogenases. Reduced NADP was more tightly controlled at the normal level which is regarded as evidence of an unaltered biosynthetic potential in this disease. In conjunction with earlier data the results indicate a preserved glycolytic and pentose shunt activity while the mitochondria display signs of dysfunction.

Adult↗
PubMed1975

Bioluminescence assay of enzymes obtained from buccal epithelium by superficial scraping.

A method is presented for the simultaneous assay of buccal enzymes by measuring reduced nicotinamide adenine dinucleotide and adenosine triphosphate with the aid of the bioluminescence of luciferase extracts. The activity of glucose-6-phosphate dehydrogenase (G6PDH) was shown earlier to be increased in homogeneous leukoplakias of the oral mucosa. Since smoking has been implicated as an etiologic factor of leukoplakia, G6PDH was measured in the normal buccal epithelium of cigarette smokers. No difference was found in the activity of G6PDH between smokers and nonsmokers when related to the activity of pyruvate kinase, which is known to be invariable in healthy and leukoplakic oral mucosa. A new compact kinetic luminescence analyzer is briefly described.

Adenosine Triphosphate↗