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Biomedical subjects

H A M Neumann

Publications and source records attributed to H A M Neumann.

At least 19 recordsLinked to original sources
PubMed2006

Remote non-invasive stereoscopic imaging of blood vessels: first in-vivo results of a new multispectral contrast enhancement technology.

We describe a contactless optical technique selectively enhancing superficial blood vessels below variously pigmented intact human skin by combining images in different spectral bands. Two CMOS-cameras, with apochromatic lenses and dual-band LED-arrays, simultaneously streamed Left (L) and Right (R) image data to a dual-processor PC. Both cameras captured color images within the visible range (VIS, 400-780 nm) and grey-scale images within the near infrared range (NIR, 910-920 nm) by sequentially switching between LED-array emission bands. Image-size-settings of 1280 x 1024 for VIS & 640 x 512 for NIR produced 12 cycles/s (1 cycle = 1 VIS L&R-pair + 1 NIR L&R-pair). Decreasing image-size-settings (640 x 512 for VIS and 320 x 256 for NIR) increased camera-speed to 25 cycles/s. Contrasts from below the tissue surface were algorithmically distinguished from surface shadows, reflections, etc. Thus blood vessels were selectively enhanced and back-projected into the stereoscopic VIS-color-image using either a 3D-display or conventional shutter glasses. As a first usability reconnaissance we applied this custom-built mobile stereoscopic camera for several clinical settings:* blood withdrawal;* vein inspection in dark skin;* vein detection through iodide;* varicose vein and nevi pigmentosum inspection. Our technique improves blood vessel visualization compared to the naked eye, and supports depth perception.

Blood Vessels↗
PubMed2006

Unfavorable cardiovascular risk profiles in untreated and treated psoriasis patients.

Psoriasis is a chronic inflammatory skin disease that is associated with an increased cardiovascular risk profile. The systemic inflammation present in psoriasis, various systemic treatments for psoriasis and an increased prevalence of unhealthy life style factors may all contribute to this unfavorable risk profile. The purpose of this article is to provide an overview of what is known about these risk factors in psoriasis, the way they influence the cardiovascular risk of psoriasis patients, and what can be done to reduce this risk. Genetic studies demonstrate that psoriasis and cardiovascular disease share common pathogenic features in which, for example inflammatory cytokines like TNF-alpha and IL-1 play an important role. The chronic inflammation in psoriasis has an unfavorable effect on the cardiovascular risk profile. Multiple cardiovascular risk factors seem to be influenced; the blood pressure, oxidative stress, dyslipidemia, endothelial cell dysfunction, homocysteine levels and blood platelet adhesion. Moreover, classic cardiovascular risk factors like smoking and obesity that have an increased prevalence among patients with psoriasis, indirectly also worsen the cardiovascular risk profile by stimulating the psoriasis activity. Systemic treatments in psoriasis reduce the cardiovascular risk by diminishing the inflammation, but it should be taken into account that most therapies also have adverse cardiovascular effects like dyslipidemia, hyperhomocysteinemia and hypertension. As a consequence preventive measures may be indicated at least during long-term treatments. Prospective research is warranted to accurately estimate the increased cardiovascular risk in psoriasis, to determine the underlying processes and to consider preventive measures according to the absolute risk of cardiovascular disease. The present overview provides data to advice health care providers to pay more attention to the cardiovascular risk profile in psoriasis patients.

Cardiovascular Diseases↗
PubMed2006

[Echo-guided compression sclerotherapy using foam: an improvement in the treatment of varicose veins].

Recently, echo-guided compression sclerotherapy (ECST) using foam was introduced as an efficient and patient-friendly therapy for the treatment of varicose veins. ECST enables operation under either spinal or general anaesthetic to be avoided. Foam for phlebological use is a volatile mixture of a gas, usually air, and a small quantity of liquid with the characteristics of a detergent or soap, such as polidocanol. The product that is injected has deterging properties. It reduces the surface tension of endothelial cells resulting in the destruction of the vascular wall. The treated vessel is subsequently reduced to a fibrous cord. For small calibre varicose veins, sclerosing fluids are used. In The Netherlands, until relatively recently branch varicosities of the long and short saphenous veins were treated surgically, but ECST using foam can be successfully used to treat wide calibre varicosities. Caution is advised in treating patients who are known to have a history of open foramen ovale because of the higher risk of the occurrence of scotoma and transient cerebral ischaemia.

Humans↗
PubMed2006

Chronic inflammation in psoriasis and obesity: implications for therapy.

A recent study has shown an indisputable relationship between psoriasis and obesity. Obesity leads to a higher risk in developing psoriasis and a poorer long-term clinical outcome of psoriasis. Furthermore, loosing weight may improve the psoriasis. A network of pro-inflammatory cytokines (especially tumour necrosis factor alpha (TNF-alpha)) is believed to play an important role in the pathophysiology of both obesity and psoriasis. The chronic low-level inflammation- as seen in obesity--may contribute to the extent of psoriatic lesions in obese patients. TNF-alpha in obesity is presumed to be derived from inflammatory cells (macrophages) in the adipose tissue and in psoriasis from activated T cells. Several drugs, such as peroxisome proliferator activated receptor (PPAR)-gamma agonists and TNF-alpha blocking agents, that target the pro-inflammatory pathways involved in both psoriasis and obesity have proven their benefit in the treatment of these entities. Furthermore, changes in levels of metabolic hormones as ghrelin and leptin in obesity may also play a role in the pathogenesis of deterioration of psoriasis by their potency to release pro-inflammatory mediators (e.g. interleukin (IL) 6 and TNF-alpha). We hypothesize that the treatment of obese psoriasis patient could be focused on reducing the obesity-induced inflammation. Reducing this obesity-induced inflammation may finally lead to a better clinical outcome. Weight loss could lead to a less inflammatory state by reducing concentrations of TNF-alpha, IL-6, leptin and improving insulin sensitivity.

Chronic Disease↗
PubMed2006

[New systemic treatments for psoriasis: etanercept, infliximab, adalimumab, efalizumab and alefacept].

The chronic skin disease psoriasis frequently requires long-term systemic treatment with agents that suppresses the immune system with little specificity, which can lead to systemic side effects. Today, using recombinant techniques, it is possible to produce modified proteins, the so-called biologicals, that target specific molecules in the inflammatory process. For the biologicals etanercept, infliximab, adalimumab, efalizumab and alefacept, the clinical efficacy expressed in the rates of partial remission (75% reduction in skin lesions) in patients with plaque psoriasis range from 12 to 88%, compared with 22 to 87% for existing systemic therapies for psoriasis. The side effects of biologicals are usually mild to moderate, but can sometimes be severe. The biologicals should be prescribed with caution, given that they have been on the market for a relatively short period, and because all forms of immune suppression carry an increased risk of oncologic degeneration. The guideline of the Dutch Society of Dermatology and Venereology states that the use of a biological may be considered when a patient cannot tolerate or is unresponsive to conventional systemic therapy, or has an increased risk of adverse events. Biologicals increase the number of options for treatment-resistant plaque psoriasis, which allows therapy to be tailored to the individual patient.

Adalimumab↗
PubMed2006

[The pathogenesis of inflammatory dermatoses, especially psoriasis].

The skin contains a variety of cell types and mediators, which together constitute the skin's immune system and play a key role in protecting the human body against dangers from outside. Dysregulation of the skin's immune system, however, frequently occurs and can result in undesirable inflammatory processes in the skin. A typical example of an undesirable inflammation in the skin is the chronic inflammatory skin disease psoriasis. In the pathogenesis of psoriasis, both genetic and environmental factors play a key role. In psoriasis, the complex interactions between T-lymphocytes, antigen-presenting cells, keratinocytes and pro-inflammatory cytokines and chemokines are disturbed. The two most widely accepted hypotheses are: (a) psoriasis is a T-cell mediated autoimmune disease, and (b) psoriasis is the result of a too finely adjusted system for regulating inflammation in the skin. The result of both mechanisms is a chronic inflammatory reaction fuelled by pro-inflammatory type-I cytokines that lead to the psoriasis-skin phenotype. With the development ofbiologicals, it has become feasible to target specific molecules in the immune process, for example type-I cytokines and the molecules present on pathogenic T-cells. This approach has already proved successful in the treatment of rheumatoid arthritis and Crohn's disease, creating novel therapeutic options for psoriasis and other inflammatory dermatoses.

Autoantibodies↗
PubMed2006

Do systemic antibiotics increase the survival of a full thickness graft on the nose?

BACKGROUND: Full thickness grafts on the nose do not always heal without problems. Partial or entire necrosis of the graft is likely to lead to less favourable cosmetic results and prolonged wound care. No consensus exists as to the use of systemic antibiotics to increase the success rate of survival of a full thickness skin graft on the nose after non-melanoma skin cancer surgery. OBJECTIVE: The objective of the study was to evaluate the effect of systemic antibiotics on the survival of full thickness grafts on the nose. METHODS: We performed a randomized, controlled trial in which we compared azithromycin with standard treatment in 30 patients, who underwent a full thickness graft reconstruction of a surgical defect on the nose after surgery for non-melanoma skin cancer. Percentage survival of the graft was the main outcome measure. RESULTS: A statistically significant difference in favour of the grafts treated with azithromycin was seen (P=0.002). Of all the variables analysed, only smoking had a significant negative effect on the survival of the graft. CONCLUSIONS: Systemic antibiotics with an accurate bacterial spectrum should be advised in full thickness skin graft reconstruction after surgery for non-melanoma skin cancer of the nose. Smoking should be strongly discouraged.

Aged↗
PubMed2005

[The practice guideline 'The STD consultation' from the Dutch College of General Practitioners; a response from the perspective of dermatology].

Sexually transmitted diseases (STDs) constitute an important health problem in the Netherlands. Although there are several STD outpatient clinics, such facilities remain unavailable outside the larger cities. The members of the Dutch College of General Practitioners, who published the practice guideline on STD consultation, provide the majority of STD care. An important aspect of this guideline is the fact that GPs are able to assess the risk by taking a sexual history and then determine their own policy on additional investigations. This prevents the omission of investigations that would exclude an STD, but carries the risk, at least theoretically, that it may be missed. It is noteworthy that scabies is not discussed in these guidelines. The most important difference between the guidelines followed by dermatological/STD clinics throughout the Netherlands is the level of triage practiced by GPs. It seems that GPs have a well-thought out and responsible policy, which also merits attention from dermatologists/venereologists.

Dermatology↗
PubMed2005

[The feasibility of the razor-blade shave technique in the diagnosis and treatment of benign and malignant skin lesions on the face].

The razor-blade shave technique uses a slightly-curved classic razor blade to shave and remove the exophytic part of a skin lesion and part of the intradermal structure down to the stratum papillare. It can then be sent for pathology investigations. This treatment is curative for many benign skin conditions. The cosmetic result ofthe razor-blade technique is superior to that of surgical excision. The razor-blade technique is useful as a biopsy instrument in the diagnosis of skin rumours of unknown nature, especially in keratoacanthomas. The technique is very easy and cheap. However, if the skin lesion is a suspected malignant melanoma, traditional surgical excision should be performed. The shave technique is not suitable for malignant skin tumours.

Biopsy↗
PubMed2005

[The wider application of photodynamic therapy in dermatology].

Photodynamic treatment is increasingly employed in the detection and treatment of malignant and non-malignant skin disease. --Indications for photodynamic therapy so far are actinic keratosis, Bowen's disease and superficially growing basal cell carcinomas, and probably verrucae and acne vulgaris. --This technology is also currently under investigation for fluorescence diagnostics oftumour margins. --The exact position of photodynamic therapy has not yet been established because there are too less long-term comparative studies demonstrating its effectiveness. --Based on the short-term results, photodynamic therapy deserves a place within the total therapeutic arsenal of the dermatologist of today for the indications mentioned above.

Aminolevulinic Acid↗
PubMed2005

Definition of the post-thrombotic syndrome, differences between existing classifications.

BACKGROUND: Accepted diagnostic criteria exist for the diagnosis of deep vein thrombosis (DVT). However, no uniform definition for the diagnosis and treatment of the post-thrombotic syndrome (PTS) exists. We examined the various definitions of PTS that are used and their relationships with invasive venous pressure measurement. METHODS: Patients who had previously suffered a documented DVT underwent clinical evaluation of both lower limbs in which we used five clinical definitions to grade PTS. We included the definition of Widmer, the CEAP classification, the venous clinical severity score (also without compression therapy), and the definitions according to Prandoni and Brandjes in the evaluation. We compared all the clinical scoring systems with invasive ambulatory venous pressure measurement. RESULTS: In total 124 patients were enrolled in whom both legs were evaluated. Thirteen patients had previously suffered bilateral DVT and nine patients had had an ipsilateral recurrent DVT. In the limbs with DVT, 10 (7%) to 29 (21%) were defined as severe PTS, compared to 0-4 (4%) in the control legs. Mild-to-moderate PTS in the DVT legs ranged from 23 to 49%, compared to 13-34% in the control legs. Overall the presence of any PTS in the DVT legs varied from 30% (VCS without compression) to 66% (Brandjes). The scoring systems of Brandjes and VCS showed a tendency towards more legs to be defined as severe PTS. Absolute frequencies of PTS in DVT legs were highest for the classifications according to Widmer, Prandoni and Brandjes. Differences in proportions of any PTS calculated between DVT and control legs varied from 18 to 39%, while odds ratios varied between 2.2 and 5.2 for the different definitions. The CEAP classification and definition of Brandjes show a moderate relation to Widmer, kappa=0.53 and 0.52, respectively. The VCS shows in all comparisons a poor correlation (kappa 0.22-0.41). Prandoni has a moderate correlation with most definitions (kappa 0.40-0.44). CONCLUSION: All clinical definitions of PTS were highly associated with the reference standard of ambulatory venous pressure, with higher AVPs observed in the more severely affected groups. The ability of the scoring systems to discriminate between DVT and control legs as well as the observed prevalence of PTS differed substantially. In part this is due to the considerable overlap in AVP in the different clinical groups, reflecting the fact that our reference standard has substantial deficiencies. No clear advantage was found in any one system of classification over the rest.

Bandages↗
PubMed2005

Molecular aetiology and pathogenesis of basal cell carcinoma.

Recent insights into the cell biology of the epidermis and its appendages are transforming our understanding of the pathogenesis of basal cell carcinoma (BCC). The significant progress that has been made warrants a comprehensive review of the molecular and cellular pathology of BCC. The items addressed include environmental and genetic risk factors, the biology of the putative precursor cell(s), and the contribution of aberrations in processes such as apoptosis, cell proliferation, differentiation and signalling to carcinogenesis. Furthermore, established and novel treatment modalities are discussed with particular attention to future biological approaches.

Apoptosis↗
PubMed2004

[Diagnosis of pigmented skin lesions: how to recognize a malignant melanoma].

An accurate answer to the clinical question of whether a pigmented skin lesion has become a malignant melanoma or not is difficult because of the clinical variability of this lesion. Because of the low incidence of 2400 new melanoma cases each year in The Netherlands, a general practitioner only sees one new case every 3-4 years. The best way to distinguish between a benign lesion and a malignant melanoma is the combined use of several criteria, such as in the ABCD-formula: asymmetry, border irregularity, colour variation and a diameter > 6 mm. Dermatoscopical examination, provided that the technique is used by well-trained and experienced physicians, is a valuable adjunct to clinical examination. A pigmented lesion should always be excised if there is not enough convincing evidence to exclude its malignant nature. Histological classification of pigmented lesions may prove difficult because of morphological overlap between benign and malignant melanocytic tumours.

Diagnosis, Differential↗
PubMed2004

Non-pharmaceutical measures for prevention of post-thrombotic syndrome.

BACKGROUND: Post-thrombotic syndrome (PTS) is a long-term complication of deep vein thrombosis (DVT) characterised by chronic pain, swelling and skin changes in the affected limb. One in every three patients with DVT will develop post-thrombotic complications within five years. OBJECTIVES: To determine the relative effectiveness of, and the rate of complications using non-pharmaceutical interventions in patients with DVT in the prevention of PTS. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group Specialised Trials Register (last searched January 2003), and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 4, 2002). In addition, hand searching of non-listed journals and personal communications with researchers was undertaken. SELECTION CRITERIA: Randomised controlled trials (RCTs) of non-pharmaceutical interventions, such as bandaging and elastic stockings in patients with clinically confirmed DVT. The primary outcome was the occurrence of PTS. There was no restriction on date or language. One reviewer (DNK) identified and assessed titles and abstracts for relevance. This was verified independently by a second reviewer (RS). DATA COLLECTION AND ANALYSIS: Data extraction was undertaken independently by two reviewers (DNK, RS), using data extraction sheets. MAIN RESULTS: Three RCTs that evaluated compression therapy were identified. Two studies compared elastic compression stockings with a pressure of 30-40 mm Hg at the ankle with no intervention applied directly after an episode of DVT. The other small study compared elastic compression stockings (pressure 20-30 mm Hg) with stockings that were one to two sizes too large in patients one year after DVT. Overall, in the treatment group at two years, the use of elastic compression stockings was associated with a highly statistically significant reduction in the incidence of PTS with odds ratio (OR) 0.31 (95% confidence interval (CI) 0.20 to 0.48). In addition, the incidence of severe PTS was reduced from OR 0.39 (95% CI 0.20 to 0.76). In another RCT that considered the first nine days post DVT, no difference in the incidence of pulmonary embolism and size of thrombus in the femoral vein was found. A statistically significant reduction (p <0.05) was found in pain, swelling and clinical scores, favouring the compression group. REVIEWER'S CONCLUSIONS: There is substantial evidence that elastic compression stockings reduce the occurrence of PTS after DVT. No serious adverse effects were mentioned in the studies. Hence, elastic compression stockings should be added to the treatment of DVT to prevent the development of post-thrombotic syndrome.

Bandages↗
PubMed2004

Human follicular stem cells: their presence in plucked hair and follicular cell culture.

BACKGROUND AND OBJECTIVES: A considerable portion of the hair follicle remains attached to plucked hair and can be used for follicle cell culture. In this study we have phenotyped these cells in an attempt to identify the stem cell fraction. Reports in the literature have indicated that this cell population may be positive for cytokeratin (CK) 19. Because stem cells in general need to be protected from apoptosis, the presence of the apoptosis-suppressing Bcl-2 protein, together with the absence of the apoptosis-promoting Bax and the CK profile may be used as an indicator of the stem cell population in the hair follicle, and in cultures of hair follicle cells. METHODS: Hair follicles from skin biopsies and plucked hair were derived from the scalps of healthy volunteers. Follicular cells were cultured from the plucked hairs. These hair follicles, plucked hairs and cultured cells were examined for their CK profiles, which are indicative of the type of cell (basal/stem cells) and for their status with respect to the proliferation marker Ki-67, Bax and Bcl-2. RESULTS: We found coexpression for CK19 and Bcl-2, but not Bax in two distinct areas, localized in the upper and lower third of the follicle from both skin biopsies and plucked hairs, while proliferation markers were negative in these areas. CK19 and Bcl-2 were also coexpressed in combination in a fraction of the follicular cell culture. The skin basal cell marker CK14 could be found throughout the outer root sheath of the hair follicle from both skin biopsies and plucked hairs, as well as in the follicular cell culture. CONCLUSIONS: Thus, CK19/Bcl-2-positive and Bax-negative cells can be obtained from cells derived from plucked hair and are retained in cultures made from these cells. If this phenotype represents follicular stem cells, our finding endorses the assumption that stem cells are located in the bulge area of the hair follicle, as we did not find them in or near the dermal papilla.

Adult↗
PubMed2004

Mohs' micrographic surgery for treatment of basal cell carcinoma of the face--results of a retrospective study and review of the literature.

BACKGROUND: The incidence of skin cancer and especially basal cell carcinoma (BCC) has increased in the last decade and is still increasing. Many treatment modalities can be used to treat BCC; surgical excision is the most frequently used. Mohs' micrographic surgery (MMS) is an advanced excision technique which is often used to treat BCC in the U.S.A. In Europe it is practised less frequently. OBJECTIVE: The aim of this article was to evaluate the efficiency of MMS for the treatment of facial BCC. METHODS: In a retrospective study recurrence rates after the treatment of facial BCC by MMS were estimated by reviewing the records of all patients with BCCs (620 patients with 720 BCCs) treated by MMS in our department from April 1992 until December 1999. RESULTS: The 5-year recurrence rates estimated from this study were 3.2% for primary BCC and 6.7% for recurrent BCC. Prognostic factors for recurrence are: an aggressive histopathological subtype, more than four Mohs' stages, a large defect size and a recurrent BCC. CONCLUSION: Based on the fact that MMS provides the lowest recurrence rates, it is the treatment of first choice for primary facial BCCs with an aggressive histopathological subtype and for recurrent BCCs in the face.

Adult↗
PubMed2004

A method for measuring the dynamic behavior of medical compression hosiery during walking.

BACKGROUND: . Compression therapy is effective in patients suffering from venous disease. This therapy has proven to be especially effective in the ambulant patient. Therefore, the dynamic behavior of the medical compression hosiery (MCH) is more important than the static one in the treatment of patients. OBJECTIVE: . The objective of this study was to develop a method for investigating the dynamic behavior of MCH during walking. METHODS: . The changes in the circumference of the lower leg equipped with a MCH are registered on a treadmill. The dynamic movement is then exactly simulated using an artificial leg-segment model equipped with the same MCH. The dynamic behavior of the MCH can thus be investigated using this artificial leg-segment model. The dynamic stiffness index can be calculated from the dynamic pressure and circumference signals. RESULTS: The expansion of the MCH was only limited to the area underlying the expanding muscles and did not spread circularly. This resulted in relatively high pressure exerted by the MCH on the underlying tissues during walking. Insertion of nonelastic material into the MCH overlying the expanding muscles increased the dynamic pressure. CONCLUSIONS: The active behavior of the MCH during normal walking differed considerably from its passive behavior. We defined a new characteristic of the MCH: the dynamic stiffness index based on the dynamic pressure profile. Insertion of nonelastic materials into the MCH covering overlying the expanding muscles increased the dynamic stiffness index.

Adult↗