Delayed neuromuscular fatigue recovery unveils reduced fatigue tolerance in elderly following maximal intermittent exercise.

The aim of the study was to assess the impact of aging on neuromuscular fatigue and recovery. Ten young (23.08 ± 1.43 years) and older (61.19 ± 1.80 years) males performed an intermittent maximal isometric exercise with the knee extensors followed by 27 min of recovery. Maximal voluntary contraction (MVC), total work (W'), voluntary activation (VA), potentiated resting twitch (Ptw), and electromyography (EMG) were recorded and then analyzed. Peripheral and central fatigue following exercise were lower in old compared to young (- 29.99% vs. - 42.68% and - 14.55 vs. - 20.02%; P < 0.05, respectively). Despite old performing 50% less work, RMS/Mmax reduction was similar between old and young (- 26.46% vs. - 29.93%; P > 0.05, respectively). During the recovery period, our results showed that recovery of the MVC was impaired for old (14.93% for old vs. 30.66% for young) and still incomplete until 27 min.VA increased significantly compared to post exercise after 1 min only for young (P = 0.001), potentially affecting the recovery pattern of MVC during the early phase due to their significant correlation (r2 = 0.58, P = 0.01). Peripheral fatigue recovery was also lower for old (11.18% vs. 18.72%; P < 0.001), and both groups failed to recover their baseline value (both P < 0.005). The lower peripheral and central fatigue observed in elderly following exercise appears for the first instance as a fatigue resistance. However, the delayed neuromuscular recovery reveals instead a reduced fatigue tolerance reflecting age-related alteration within contractile properties and/or within central nervous system.

Peripheral fatigue regulation during knee extensor exercise in type 1 diabetes and consequences on the force-duration relationship.

PURPOSE: This study aimed to examine if peripheral fatigue is adjusted during knee extensor (KE) exercise in order not to surpass a critical threshold patient with type 1 diabetes (T1D) and the consequences of this mechanism on the force-duration relationship. METHODS: Eleven T1D individuals randomly performed two different sessions in which they performed 60 maximum voluntary contractions (MVC; 3 s contraction, 2 s relaxation). One trial was performed in the non-fatigued state (CTRL) and another after fatiguing neuromuscular stimulation of the KE (FNMES). Peripheral and central fatigue were quantified by the difference between pre and post exercise in quadriceps voluntary activation (ΔVA) and potentiated twitch (ΔPtw). Critical torque (CT) was determined as the average force of the last 12 contractions, whereas W' was calculated as the area above the CT. RESULTS: Although FNMES led to a significant decrease in potentiated twitch (Ptw) before performing the 60-MVCs protocol (p < 0.05), ΔVA (∼ -7.5%), ΔPtw (∼ -39%), and CT (∼816 N) post-MVCs were similar between the two conditions. The difference in W' between CTRL and FNMES was correlated with the level of pre-fatigue induced in FNMES (r2 = 0.60). In addition, W' was correlated with ΔPtw (r2 = 0.62) in the CTRL session. CONCLUSION: Correlative results in the present study indicate that regulating peripheral fatigue mechanisms at a critical threshold limit W'. Additionally, peripheral fatigue during KE exercise is limited to an individual threshold in T1D patients.

Hemodynamic and neuromuscular basis of reduced exercise capacity in patients with end-stage renal disease.

PURPOSE: The present study aimed to characterize the exercise-induced neuromuscular fatigue and its possible links with cerebral and muscular oxygen supply and utilization to provide mechanistic insights into the reduced exercise capacity characterizing patients with end-stage renal disease (ESRD). METHODS: Thirteen patients with ESRD and thirteen healthy males (CTR group) performed a constant-force sustained isometric contraction at 50% of their maximal voluntary isometric contraction (MVC) until exhaustion. Quadriceps muscle activation during exercise was estimated from vastus lateralis, vastus medialis, and rectus femoris EMG. Central and peripheral fatigue were quantified via changes in pre- to postexercise quadriceps voluntary activation (ΔVA) and quadriceps twitch force (ΔQtw,pot) evoked by supramaximal electrical stimulation, respectively. To assess cerebral and muscular oxygenation, throughout exercise, near-infrared spectroscopy allowed investigation of changes in oxyhemoglobin (∆O2Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the prefrontal cortex and in the vastus lateralis muscle. RESULTS: ESRD patients demonstrated lower exercise time to exhaustion than that of CTR (88.8 ± 15.3 s and 119.9 ± 14.6 s, respectively, P < 0.01). Following the exercise, MVC, Qtw,pot, and VA reduction were similar between the groups (P > 0.05). There was no significant difference in muscle oxygenation (∆O2Hb) between the two groups (P > 0.05). Cerebral and muscular blood volume (∆THb) and oxygen extraction (∆HHb) were significantly blunted in the ESRD group (P < 0.05). A significant positive correlation was observed between time to exhaustion and cerebral blood volume (∆THb) in both groups (r2 = 0.64, P < 0.01). CONCLUSIONS: These findings support cerebral hypoperfusion as a factor contributing to the reduction in exercise capacity characterizing ESRD patients.

Blunted cerebral hemodynamic responses to incremental exercise in patients with end-stage renal disease.

PURPOSE: The aims of this study were to compare cerebral hemodynamics and maximal oxygen uptake (VO2peak) in patients with end-stage renal disease (ESRD) vs. age-matched healthy controls during maximal exercise. METHODS: Twelve patients with ESRD and twelve healthy adults (CTR group) performed exhaustive incremental exercise test. Throughout the exercise test, near-infrared spectroscopy allowed the investigation of changes in oxyhemoglobin (∆O2Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the prefrontal cortex. RESULTS: Compared to CTR, VO2peak was significantly lower in ESRD group (P < 0.05). Increase in ∆THb (i.e., cerebral blood volume) was significantly blunted in ESRD (P < 0.05). ESRD patients also had impaired changes in cerebral ∆HHb and ∆O2Hb during high intensity of exercise (P < 0.05). Finally, no significant correlation was observed between VO2peak and changes in cerebral hemodynamics parameters in both groups (All P > 0.05). CONCLUSION: Maximal exercise highlights subtle disorders of both hemodynamics and neuronal oxygenation in the prefrontal cortex in patients with ESRD. This may contribute to both impaired cognitive function and reduced exercise tolerance throughout the progression of the disease.

Histiocytosis X revealed by diabetes insipidus and skin lesions.

Langerhans cell histiocytosis is part of a larger group of syndromes described as histiocytoses. The disease may involve single or multiple systems including skin and nervous system. Here we report an adult case where Langerhans cell histiocytosis presented with diabetes insipidus and cutaneous ulcers.

Oral HPV infection and MHC class II deficiency (A study of two cases with atypical outcome).

BACKGROUND: Major histocompatibility complex class II deficiency, also referred to as bare lymphocyte syndrome is a rare primary Immunodeficiency disorder characterized by a profondly deficient human leukocyte antigen class II expression and a lack of cellular and humoral immune responses to foreign antigens. Clinical manifestations include extreme susceptibility to viral, bacterial, and fungal infections. The infections begin in the first year of life and involve usually the respiratory system and the gastrointestinal tract. Severe malabsorption with failure to thrive ensues, often leading to death in early childhood. Bone marrow transplantation is the curative treatment. CASE REPORTS: Here we report two cases with a late outcome MHC class II deficiency. They had a long term history of recurrent bronchopulmonary and gastrointestinal infections. Bone marrow transplantation could not be performed because no compatible donor had been identified. At the age of 12 years, they developed oral papillomatous lesions related to HPV (human papillomavirus). The diagnosis of HPV infection was done by histological examination. HPV typing performed on the tissue obtained at biopsy showed HPV type 6. The lesions were partially removed after two months of laser treatment. CONCLUSIONS: Viral infections are common in patients with MHC class II and remain the main cause of death. Besides warts caused by HPV infection do not exhibit a propensity for malignant transformation; they can cause great psychosocial morbidity.

Pseudotumoral cutaneous aspergillosis in chronic granulomatous disease, report of a pediatric case.

Invasive aspergillosis is a life-threatening condition in patients with chronic granulomatous disease (CGD). Skin invasion by Aspergillus occurs most commonly by contiguity to a neighboring cavity. We describe an unusual case of invasive cutaneous aspergillosis presented as a large burgeoning tumor in a 4-year-old girl with CGD who underwent surgical treatment for bifocal osteomyelitis of the left leg. The skin invasion occurred 4 months after a "successful" treatment of invasive pulmonary aspergillosis. Atypical presentation and diagnostic difficulties are discussed. Invasive cutaneous aspergillosis may be polymorphic. The diagnosis should be considered early in the etiological investigation of any suspicious skin lesions in CGD even in uncommon aspects such as burgeoning tumors.

Cutaneous adverse drug reactions in children. A series of 90 cases.

BACKGROUND: Cutaneous adverse drug reactions (CADR) are frequent in children. They have different clinical presentations and may be caused by several drugs. AIM: To evaluate the epidemioclinical features of cutaneous adverse drug reactions (CADR) and the different causative drugs in a Tunisian paediatric series. METHODS: We have retrospectively included 90 children (under 16 years old) with a well documented cutaneous drug reaction, seen in the Department of Dermatology of Charles Nicolle hospital of Tunis over 18 years (1991-2008). Age, gender, duration of skin disorders, type of cutaneous lesions, incriminated drugs, delay between drug consumption and eruption, validation by the national pharmacovigilance centre, treatment and outcome were recorded. RESULTS: Our patients were 6.9 year-aged (sex-ratio M/F 1.19). They had maculopapular eruption (MPE) (57.7%), acute urticaria (16.6%), fixed drug eruption (14.4%), erythema multiform (2.2%), photosensitization (1.1%) or severe cutaneous drug reactions (10%).Incriminated drugs were: Antibiotics (55.5%), non-steroidal antiinflammatory drugs (18.8%), antiepileptics (11.1%), and analgesics (5.5%). Betalactamins were the most commonly incriminated antibiotics (32 out of 50 patients; 64%). Barbiturates were the most commonly incriminated anti-epileptics (7/90 cases, 7.7%). Favourable outcome was noted in all patients, even those with severe drug reactions. CONCLUSION: MPE to antibiotics were the most common kinds of CADR in children. Drug responsibility should be based on solid criteria given the frequency of MPE of infectious origin and the frequent prescription of antibiotics in paediatric population.

[Kindler syndrome: clinical and ultra-structural particularities, a propos of three cases]. / Le syndrome de Kindler, particularités cliniques et ultrastucturales à travers trois nouvelles observations familiales.

INTRODUCTION: Kindler's syndrome is a rare type of genetic skin condition belonging to the class of bullous poikilodermia. We report three new sibling cases of this rare syndrome. CASES REPORTS: The condition was seen in three sisters aged 12, 16 and 20 years, born of a first-degree consanguineous marriage with no family history of Kindler's syndrome. The three patients presented spontaneously regressive bullous eruptions, poikilodermia of gradual onset, major cutaneous atrophy on the back of the hands and the feet, photosensitivity and gingival hypertrophy. Electron microscopy examination of poikilodermic skin showed normal anchoring filaments and intraepidermal cleavage. DISCUSSION: Diagnosis of Kindler's syndrome is based upon clinical evidence. Kidler's syndrome is a well defined clinical entity. Ultra-structural studies show intraepidermal, junctional, and dermal cleavage. This syndrome must be differentiated from congenital epidermolysis bullosa, Weary's syndrome, and other bullous hereditary poikilodermas.

Pigmented lesion in the inguinal region.

Pigmented Bowen disease (PBD) is a rare tumor characterized by increased melanin pigment in the epidermis or papillary dermis in addition to the typical findings of Bowen disease. We report the case of a 60-year-old woman who presented with a 6-month history of a gradually enlarging solitary dark brown plaque in her right inguinal region. Histopathology showed hyperkeratosis with parakeratosis, acanthosis, disorganization of epidermal architecture, atypical keratinocytes, and increased melanin pigment of the papillary dermis. Considering the clinical and the histological evidence, a diagnosis of PBD was established. Complete resection confirmed the diagnosis. Pigmented Bowen disease is an unusual form of squamous carcinoma in situ. Other tumors in the differential diagnosis include pigmented basal cell carcinoma and superficial spreading melanoma.

Erythema elevatum diutinum: an "idiopathic" case.

Erythema elevatum diutinum (EED) is a rare condition with an unclear pathogenesis. Initially classified within neutrophilic dermatoses, it is now considered as a leukocytoclastic vasculitis accordingly to its histopathologic pattern. Several clinical presentations as well as many associated diseases are reported in the literature. We report a new case of EED in a 58-year-old man who presented with a three-month history of plaques and nodules on the extensor surfaces of hands, elbows, knees, ankles, forearms, and buttocks. Histology showed a leucocytoclastic vasculitis, suggestive of the diagnosis of EED. Screening for an associated pathology, namely a paraproteinemia or a solid cancer, was negative. Treatment with dapsone leads to amelioration within few weeks.

Generalized peeling skin syndrome: Case report and review of the literature.

Peeling skin syndrome (PSS) is a rare form of ichthyosis with a probable autosomal recessive inheritance that exhibits superficial, painless, continual, or seasonal cutaneous exfoliation. The syndrome generally appears at birth or in infancy. We report a case of generalized PSS and provide a literature review. A 34-year-old woman reported a lifelong history of generalized and painless peeling of the skin that worsened in summer. Her parents were third degree cousins. Her twin sister and her two cousins presented with the same condition. Physical examination showed widespread superficial sheets of variable size that could be easily removed without bleeding or pain. No underlying erythema was noted. Otherwise, the patient was in good health. Histological findings showed an epidermal cleavage within the stratum corneum. The generalized form of PSS is classified into 3 types, A, B, and C, according to the classification system of Traupe and Mevorah. We have tried to classify the cases of generalized PSS already reported in the literature into one of these three types. Thirteen reported cases probably presented PSS-type A. Sixteen patients are best described as PSS-type B. Two patients exhibit PSS-type C. Fifteen reported patients had an acral form of peeling skin syndrome. The classification of the eleven remaining patients was difficult to determine. Our patient presented clinical and histological features of generalized PSS-type A.

Identification of Malassezia species from Tunisian patients with pityriasis versicolor.

BACKGROUND: Pityriasis versicolor is caused by Malassezia sp. It is a common worldwide mycosis. Recently, eleven species are known of the Malassezia genus, and are identified in vitro by their morphological characteristics, biochemical tests and by molecular biology. The aim of this study is the identification of Malassezia species from Tunisian patients with pityriasis versicolor. METHODS: Specimens were taken from 58 patients with pityriasis versicolor. All samples were both inoculated in Sabouraud dextrose agar and Sabouraud agar overlaid with olive oil. Malassezia species were identified by morphological and physiological methods: macroscopy, microscopy, catalase, urease and lipid assimilation tests. RESULTS: We have isolated five Malassezia species: Malassezia globosa being isolated in 76.2% of patients, followed by Malassezia furfur (9.55%), Malassezia sympodialis (4.75%), Malassezia slooffiae (4.75%) and Malassezia pachydermaties (4.75%). CONCLUSION: In our study Malassezia globosa presents the main species implicated in the pathogenicity of pityriasis versicolor and Malassezia furfur as the second agent of importance.

[Orf of the hand]. / Orf de la main.

INTRODUCTION: The orf is a zoonotic infection which can be transmitted to humans. OBJECTIVE: The aim of our report is to describe this often misdiagnosed viral infection in a man with an orf of the hand appearing after the feast of the sacrifice. CASE REPORT: A 40-year-old man with no past medical history, presented with a nodular lesion on the fifth right finger evolving for 3 weeks which had appeared 2 weeks after the feast of the sacrifice. Histology showed a vacuolar degeneration of keratinocytes probably of viral origin. Both histological aspect and the contact with sheep, led to the diagnosis of hand orf. Three weeks later the lesion had spontaneously resolved. CONCLUSION: Orf is an infectious mucocutaneous disease due to a parapoxvirus. It is more frequent in professionally exposed persons (veterinary, butchers...). But, in our country, the frequency of the orf increases after the feast of the sacrifice and remains undiagnosed because patients do not consult. The diagnosis may be confirmed by electron microscopy, conventional histopathology or by isolation of the virus by PCR. Information on the benign character of the disease and reassurance of the infected patient are very important because lesion usually resolves spontaneously.

[Localized scleroderma: a retrospective study about 92 cases]. / Les sclérodermies localisées: étude rétrospective de 92 cas.

BACKGROUND: Sclerodermas are rare affections which can be located or generalized. Localized form is the most frequent. AIM: The purpose of this study was to describe epidemiologic, clinics, biological, immunological, therapeutic, evolutionary characteristics of the localized scleroderma through a personal series and the data of the literature. METHOD: We have performed a retrospective study on all patients followed in the department of dermatology of the Hospital Charles Nicole during 14 years period. RESULTS: Our study was about 92 cases of localized scleroderma (73 were females and 19 males). The mean age was 35 years (between 2 and 72 years). The majority of localised sclerodermas (66.2% of the cases) appeared before 40 years with a maximum of frequency between 10 and 30 years (41.6%). Only 11.9% of the cases were observed before 10 years. They were 51 cases (55%) of morphea, 35 cases (38%) of scleroderma in bands including 32 linear scleroderma and 3 scleroderma en coup de sabre, 5 cases (5.5%) of generalized morphea and 1 case (0.15%) of deep morphea. Average therapeutic was specified among 63 patients (87%), and the evolution could be appreciated among 45 patients. CONCLUSION: The epidemiologic data observed in our series are comparable with those reported in the literature. Therapeutic difficulties and risks of functional after-effects, particular in scleroderma in bands, remain the principal concern for all the authors.

[Bullosis diabeticorum: report of ten cases]. / La bullose des diabétiques: a propos de dix cas.

BACKGROUND: Bullosis diabeticorum is a rare characteristic complication of diabetes mellitus; it affects 0.5% of diabetics. Bullosis diabeticorum is a manifestation of complicate and longstanding diabetes mellitus. THE AIM: of our study was to describe particularities of diabetes in patients suffering of this disease. METHODS: We have led a retrospective study covering a 5 year-period (January 2001 - December 2007) in the dermatology department of the Charles Nicolle's hospital in Tunisia. We selected for this study all cases of bullosis diabeticorum. RESULTS: During the studied period, 10 cases have been collected. They were in all cases about complicate and long-standing diabetes. Bullosis diabeticorum has a favourable outcome in all cases with symptomatic treatment. CONCLUSION: The different cases of bullosis diabeticorum reported in our series were associated to complicate diabetes mellitus what lets suggest that vascular deteriorations led to cutaneous fragility responsible for the skin cleavage.

[What is new in the treatment of vitiligo]. / Actualites dans le traitement du vitiligo.

BACKGROUND: Vitiligo is a frequent hypomelanosis that affects 1% of the world population, and 0,95% of the tunisian population. OBJECTIVE: The objective of our study is to describe through a recent review of the literature, the different therapeutic modalities, now used in vitiligo. We have used a clinical approch to guid therapeutic indications. METHODS: We have performed a review of the articles, dealing with the treatment of vitiligo and published during the 10 previous years. We have used a Medline research with these key-words: "vitiligo and treatment". Randomized studies were privileged and 29 articles were analysed. We have initially presented all validated therapeutic means now used in vitiligo. We have then proposed, according to this recent review of the literature, clinical indications according to vitiligo type, extension of lesions and if vitiligo involves adults or children. RESULTS: We dispose of multiple chemical, physical and surgical treatments of vitiligo. Vitiligo with partial melanocyte defect can be treated especially by the different modalities of phototherapy (PUVAtherapy, PUVASOL, UVB therapy TL01, Laser excimer). Surgical treatments were also described, with there principal indications. Ethiopathgenic treatments (local steroids, Tacrolimus, Calcipotriol, Vitix*) were especially indicated in vitiligo with complete epidermic and follicular achromy. Finally, different therapeutic associations were reported in the litterature, showing synergic effect of some treatments. CONCLUSION: Phototherapy remains the best treatment of vitiligo type I. In vitiligo type II and III, ethiopathogenic treatments may be efficient, alone or associated with phototherapy.

[Hereditary ichthyosis in Tunisia: epidemiological study of 60 cases]. / Ichtyoses herediatires en Tunisie: etude epidemiologique a propos de 60 cas.

BACKGROUND: Ichthyosis are a group of inherited keratinizing disorders. The cutaneous abnormalities may be isolated or associated with extra-cutaneous symptoms. AIM: To report the epidemiological and clinical profiles of patients with these genodermatoses from a hospital tunisian study. METHODS: A retrospective study of all cases of ichthyosis referred during a period of 5 years to the department of dermatology of Charles Nicole's hospital of Tunis. RESULTS: Sixty cases of hereditary ichthyosis were seen. The sex-ratio was of 0.5. Parental consanguinity was noted in 36 patients (60%). Seventeen patients (25.7%) had a positive familial history of ichthyosis. The clinical form of ichthyosis was determined in 52 cases. The nonbullous ichthyosiform erythroderma was observed in 25 patients (41.6%). Sixty patients presented an ichthyosis vulgaris (26.6%). The other forms of ichthyosis were rarely observed : 4 cases of X-linked recessive ichthyosis, 2 cases of lamellar ichthyosis and 2 cases of bullous ichthyosiform erythroderma. Two patients were born with collodion-like membranes. Two cases presented a complex syndrome. CONCLUSION: The NBIE, commonly considered as a rare form of ichthyosis, was the most frequently form seen in our study (41.6%), probably because of the high frequency of consanguineous marriages in Tunisia. The IV represents the most frequent form reported in the literature and was observed in 25% of our patients. The classification of some ichthyosis associated with other extracutaneous abnormalities (found in 2 of our patients) remains difficult.

[Isolated cutaneous pigmentation: adrenal insufficiency may be the cause]. / Pigmentation cutanée isolée: penser à l'insuffisance surrénale.

INTRODUCTION: Addison's disease is a primary global deficiency in adrenocortical hormones resulting from the progressive total destruction of the adrenal glands. CASE: A 15-year-old girl consulted after four months of pigmentation on sun-exposed areas, with photosensitivity. She reported no weakness, no decline in her general status, and no menstrual disorders. Cutaneous examination showed diffuse pigmentation of the face, the dorsal hands, the feet and palmar folds. Pigmented macules were also seen on the palms, soles, tongue and cheek mucosa. Blood and urinary electrolyte levels were within normal ranges. Plasma cortisol was low, plasma ACTH high, and the synacthen test negative. These findings led us to diagnose Addison's disease. Antithyroid antibodies were noted without antinuclear factors or antiadrenal antibodies. The patient was treated with hydrocortisone, 40 mg daily. Outcome was favorable. DISCUSSION: Because of the presence of isolated melanoderma of the sun-exposed areas and macular pigmentation of oral mucosa in this patient, we tested for Addison's disease: hormonal testing confirmed the diagnosis. Because our patient had no electrolyte disorders, Addison's disease might have remained unknown until the onset of acute adrenal insufficiency. Etiology in this case was probably autoimmune. In the case of persistent pigmentation of sun-exposed areas, even isolated, Addison's disease must be considered and hormonal testing performed to avoid acute adrenal insufficiency.