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Biomedical subjects

M David

Publications and source records attributed to M David.

At least 91 records · Page 5Linked to original sources
PubMed2001

Epidermal growth factor (EGF) receptor kinase-independent signaling by EGF.

The ErbB family of receptors, which includes the epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4, mediate signaling by EGF-like polypeptides. To better understand the role of the EGFR tyrosine kinase, we analyzed signaling by a kinase-inactive EGFR (K721M) in ErbB-devoid 32D cells. K721M alone exhibited no detectable signaling capacity, whereas coexpression of K721M with ErbB2, but not ErbB3 or ErbB4, resulted in EGF-dependent mitogen-activated protein kinase (MAPK) activation. The kinase activity, but not tyrosine phosphorylation, of ErbB2 was required for EGF-induced MAPK activation. The presence of tyrosine phosphorylation sites in K721M was not a requisite for signaling, indicating that transphosphorylation of K721M by ErbB2 was not an essential mechanism of receptor activation. Conversely, the mutated kinase domain of K721M (residues 648-973) and tyrosine phosphorylation of at least one of the receptors were necessary. EGF was found to activate the pro-survival protein kinase Akt in stable cell lines expressing K721M and ErbB2 but, unlike cells expressing wild-type EGFR, was incapable of activating signal transducers and activators of transcription (STAT) or driving cell proliferation. These results demonstrate that EGFR-ErbB2 oligomers are potent activators of MAPK and Akt, and this signaling does not require EGFR kinase activity.

Cell Line↗
PubMed2001

[Treatment of supravalvular pulmonary stenosis after arterial switch operations (ASO)].

The aim of this study was to evaluate the incidence of postoperative pulmonary supravalvular stenosis in patients with d-TGA and to assess the rate of success or failure of balloon angioplasty. Out of 70 patients with d-TGA 67 patients underwent successful arterial switch operation. Twelve children developed severe supravalvular pulmonary stenosis with a peak gradient above 50 mmHg (range: 50-120 mmHg). In these patients 19 high pressure dilatations were performed up to a diameter of 130% of the native valve dimension. The mean age at angioplasty was 17 months (range: 3-36 months). Successful intervention was defined as a > 50% decrease of predilatation peak pressure gradient or right ventricular pressure < 50 mmHg. Dilatations were performed without complications. Complete resolution was primarily achieved in 1 patient. In 7 patients the pressure gradients could be reduced to 10-45 mmHg (mean: 25 mmHg). In another two patients a palliative stent-implantation into the pulmonary trunk was necessary to reduce the pressure gradient. Because unsuccessful intervention, two patients needed subsequent operation. During follow-up of 6-9 months after intervention severe restenosis occurred in 3 patients (2 after stent-implantation; 1 after re-re-dilatation) who then also needed operation. Balloon dilatation should be the first treatment in patients with pulmonary stenosis after ASO in TGA owing to the low complication rate and the potential benefit of this procedure. Recurrent and combined stenoses with narrow pulmonary valve annulus should be treated surgically.

Age Factors↗
PubMed2001

Idiopathic palmoplantar eccrine hidradenitis in children.

Idiopathic palmoplantar eccrine hidradenitis (IPPH) is a recently described disorder characterized by painful erythematous plantar nodules and in three cases, showed a typical neutrophilic infiltrate around and within the eccrine sweat apparatus. Five cases of IPPH on the soles of the feet in healthy children are reported. The disorder presented after intense physical activity in four cases. The course was benign and self-limiting. Complete bed rest for several days without any medical therapy led to alleviation of the pain and disappearance of all the lesions. Conclusion. Idiopathic palmoplantar eccrine hidradenitis may be more common than reported. Paediatricians should be aware of it in order to avoid unnecessary diagnostic tests and treatments.

Chilblains↗
PubMed2001

Cardiac pheochromocytoma.

Primary pheochromocytomas of the heart are extremely uncommon. In this report, we present the case of a patient with primary cardiac pheochromocytoma arising from the interatrial septum. Metaiodobenzylguanidine-scintigraphy was negative and diagnosis was confirmed by a positive octreotide scintiscan. The tumor was removed successfully using cardiopulmonary bypass.

3-Iodobenzylguanidine↗
PubMed2001

Fracture-embolization of duromedics valve prosthesis and microscopic uncommon lesions.

We report a sudden leaflet fracture of a Duromedics mitral valve 6 years after implantation. The patient had cardiogenic shock and complained of asthenia, orthopnea, and tachycardia. Transesophageal echocardiography showed the lack of one leaflet of the prosthesis and regurgitation. An emergency mitral replacement was successfully performed. Angiographic computed tomography scan localized the sequestrum that embolized the common iliac arteries. Examination of the deficient prosthesis showed multiple lesions and, in particular, a subsurface lesion that may be characteristic of carbon pyrolytic valves.

Adult↗
PubMed2001

Novel thermoregulation system for enhancing cardiac function and hemodynamics during coronary artery bypass graft surgery.

BACKGROUND: Myocardial ischemia, arrhythmias, and coagulopathies are associated with postoperative hypothermia. This study assessed the efficacy of a novel thermoregulation system in alleviating these events during coronary artery bypass graft (CABG) surgery. METHODS: Elective CABG surgery patients were randomized into either Allon thermoregulation (AT, n = 40) or routine thermal care (RTC, n = 20) groups in whom the maintenance of normothermia during the nonbypass phases of the operation was compared. The AT used patients' rectal temperature as reference data to monitor the maintenance of the water temperature circulating at 37 degrees C in a garment. Rectal temperature, patient hemodynamics, and cardiac-specific troponin I (cTnI) levels were assessed at the induction of anesthesia, 30 minutes into surgery, at discontinuation of bypass, end of surgery, and 2 hours postoperatively. RESULTS: Body temperature was higher in the AT group compared to the RTC group at all five time points. Cardiac index (CI) (L/min) was higher in the AT group, 2.5 +/- 0.5, 2.6 +/- 0.5*, 3.2 +/- 0.6*, 3.3 +/- 0.5*, 3.1 +/- 0.7 at the respective time points, compared to the RTC group, 2.3 +/- 0.6, 2.1 +/- 0.2, 2.6 +/- 0.7, 2.7 +/- 0.7, 2.7 +/- 0.7 (*p < 0.05). Systemic vascular resistance (SVR) (dyne x s)/cm5) was consistently lower in the AT patients. Enzyme levels were elevated in both groups but were less so in the AT patients. CONCLUSIONS: The AT system can efficiently maintain normothermia. The beneficial effects are expressed by reduced SVR, elevated CI, and lower levels of cTnI, which may show a possible attenuation of myocardial injury.

Adult↗
PubMed2001

Effects of oxytocin receptor antagonist atosiban on pregnant myometrium in vitro.

OBJECTIVE: To investigate dose-dependent effects of oxytocin receptor antagonist, atosiban, on oxytocin-induced contractions of myometrial strips from healthy pregnant women. METHODS: During elective cesareans, myometrial biopsies were taken from the lower uterine segment and trimmed into 2 x 2 x 10-mm longitudinal strips within 36 hours. One hundred twenty-two myometrial strips showed regular spontaneous contractions and were used for measurement. Each myometrial strip was mounted in a physiologic organ bath, and isometric contraction activity and contractile patterns were analyzed after stimulation with oxytocin. Frequency and amplitude of contractions and area under force-time curves were determined by adding atosiban at concentrations of 1, 5, 10, 20, 50, 100, 250, and 500 microg/mL. Resulting contraction activity (at least 20 contractions per concentration) was compared with reference activity. RESULTS: Atosiban had significant inhibitory effects on myometrial contractions at concentrations as low as 1 microg/mL. Compared with reference activity (oxytocin stimulation only), resulting inhibition was higher than 50% with the lowest atosiban concentration used. This inhibition of contraction activity was dose-dependent and referred to the area under the curve, frequency, and amplitude of contractions. At high concentrations of atosiban, contraction activity was even lower than spontaneous activity without oxytocin stimulation. CONCLUSION: The oxytocin receptor antagonist atosiban showed a significant, dose-dependent inhibition of oxytocin-induced contractions of human myometrium in vitro. It might be effective in tocolysis at term.

Dose-Response Relationship, Drug↗
PubMed2001

[Acute transitory intrafamilial erythroblastopenia and hereditary spherocytosis: role of parvovirus B19].

INTRODUCTION: Acute parvovirus B19 infection induces a transient inhibition of erythroid cell formation, which may induce an erythroblastopenia crisis in patients suffering from chronic hemolytic anemia. EXEGESIS: We report here an exceptional observation of acute erythroblastopenia crisis with good outcome, occurring at the same time in a mother and her son, both suffering from hereditary spherocytosis. Diagnosis of parvovirus infection is based on detection of serum parvovirus B19-specific immunoglobulin M antibodies in the mother and her son and by the positivity of parvovirus B19 DNA detected by PCR in serum in the mother. Outcome was good, with the end of the erythroblastopenia crisis obtained 7 to 10 days later, but requiring blood transfusion in the mother. CONCLUSION: Our observation is a reminder that the contagiosity of parvovirus B19 is high in household contacts and that protection of family members should rapidly be considered in hereditary spherocytosis.

Acute Disease↗
PubMed2001

[Mayer-Rokitansky-Kuster-Hauser syndrome: associated pathologies].

UNLABELLED: MRKH syndrome (Mullerian structures agenesis in woman) is often associated with other anomalies: kidney and bone anomalies, deafness, ovarian tumors. Functional ovarian anomalies have not been previously reported. CASE REPORTS: Five new cases of MRKH syndrome are reported. They were associated with deafness in two cases, with kidney anomaly in three cases, vertebral anomalies in one case, and four suffered from obesity and ovarian dysfunction (ovarian polycystics syndrome, advanced puberty, androgenic excess). All of them had ovarian ectopy, which was responsible for false ultrasonographic diagnosis. CONCLUSION: An MRKH syndrome diagnosis implicates a search for other anomalies. Ovarian functional trouble should not let MRKH syndrome remain unrecognized.

Abnormalities, Multiple↗
PubMed2001

Molecular epidemiology of tuberculosis among eight hospitals in New York City, 1996-1997.

OBJECTIVE: To determine the molecular epidemiology of tuberculosis isolated from patients cared for at eight hospitals scattered throughout New York City. MATERIALS AND METHODS: Cases of tuberculosis occurring in 1996 and 1997 at collaborating hospitals were identified, and demographic data were extracted from patient charts. All available isolates were analyzed by IS6110 for genetic relatedness. The molecular fingerprints were compared both to each other and to the larger repository of strains from New York City developed and maintained at the Public Health Research Institute. RESULTS: One hundred and eighty cases were fully characterized. Compared with New York City cases, study patients were more likely to be Asian and less likely to be non-Hispanic blacks. Overall, 97 (54%) of the cases were clustered with respect to other study strains or with respect to the other New York City isolates. Clustered strains were significantly more likely to be from non-Hispanic blacks or patients born in the United States. The largest cluster (n = 17) was the "W" strain previously associated with an outbreak of multidrug-resistant tuberculosis in New York City. In the current study, the majority of W strain isolates were fully drug-susceptible. CONCLUSIONS: High rates of genetically related tuberculosis continue to occur among patients in New York City, in spite of improved control of nosocomial outbreaks and dramatic decreases in the overall case rates. The use of molecular techniques to suggest patterns of transmission has become essential in developing and assessing routine tuberculosis control strategies.

Adult↗
PubMed2001

Prospective randomized comparison of impedance-controlled auto-continuous positive airway pressure (APAP(FOT)) with constant CPAP.

Background: The measurement of impedance permits reliable detection of obstructive apneas, hypopneas and upper airways resistance syndrome.Objective: To establish whether impedance-controlled self-adjusting positive airway pressure therapy (APAP(FOT)) is equally as good as constant continuous positive airway pressure (CPAP) in the treatment of sleep apnea syndrome (OSAS).Methods: Twenty men and five women with OSAS (age 52.8+/-9.0 years, body mass index (BMI) 31.4+/-5.0 kg/m(2), AHI 32.2+/-18.1/h (mean+/-SD)) underwent baseline polysomnography, manual CPAP titration and two nights of treatment, one with APAP(FOT), one with constant CPAP.Results: With both modes, a significant reduction in respiratory disturbances was seen (apnea/hypopnea index (AHI) baseline 32.2+/-18.1/h, constant CPAP 6.6+/-8.7, APAP(FOT) 5.5+/-3.8/h, P<0.001 baseline vs. each treatment mode). Under APAP(FOT), the sleep profile was normalized (S3/4 baseline 16.3+/-13.9% total sleep time (TST), APAP(FOT) 21.6+/-10.9% TST, P<0.05, rapid eye movement (REM) 14.2+/-6.7% TST vs. 20.3+/-7.3% TST, P<0.01), while with constant CPAP, a tendency towards improvement was found. The mean treatment pressure with APAP(FOT) was significantly lower than the constant CPAP (5.7+/-2.1 vs. 8.3+/-1.6 mbar, P<0.001).Conclusion: We conclude that APAP(FOT) is at least as effective as constant CPAP in normalizing sleep and breathing in OSAS.

Journal Article↗
PubMed2001

Vitiligo-like leucoderma during photochemotherapy for mycosis fungoides.

We describe four patients with mycosis fungoides (MF) in whom depigmentation, and also leucotrichia in one, occurred following the resolution of the eruption during phototherapy (psoralen plus ultraviolet A treatment in three patients, climatotherapy in one). In all cases, the depigmentation was localized to the area of the pre-existing MF lesions. There was no clinically obvious phototoxicity. Biopsy study including S100 staining in all cases, and electron microscopy in one case, demonstrated the total absence of melanocytes, with no evidence of MF. It is suggested that the phototherapy may have activated a cell-mediated immunity leading to destruction of the melanocytes. We recommend that vitiligo-like leucoderma be added to the list of untoward effects of phototherapy in MF.

Adolescent↗
PubMed2001

Basic fibroblast growth factor: a potential inhibitor of glutamine synthetase expression in injured neural tissue.

Basic fibroblast growth factor (bFGF) was recently shown to promote the survival of neural cells and tissues, raising hopes for its therapeutic potential in degenerative disorders of the CNS. Here we examine the effect of bFGF on the expression of glutamine synthetase, a key enzyme in the detoxification of the neurotransmitter glutamate. Expression of this enzyme is regulated by systemic glucocorticoids and, in chick neural retina tissue, is restricted to Müller glial cells. We report that exogenous supply of bFGF to retinal explants inhibits hormonal induction of glutamine synthetase expression. This inhibition appears to be mediated by the c-Jun protein which accumulated, in response to bFGF, exclusively in Müller glial cells. Ischemic conditions, which reportedly stimulate the release of endogenous bFGF, also led to an increase in c-Jun protein and a decline in glutamine synthetase expression. This decline could be competitively prevented by a soluble fibroblast growth factor receptor but not by a soluble epidermal growth factor receptor. The finding that endogenous release of bFGF or its exogenous supply down-regulates glutamine synthetase expression suggests that in addition to its reported neuroprotective effect, bFGF may exacerbate glutamate mediated neurotoxicity through direct down-regulation of glutamine synthetase.

Animals↗
PubMed2001

[Female menopause--comparison of knowledge and opinion in German and Turkish-born women].

320 German and 262 Turkish immigrant patients of the gynaecological units of the Virchow Women's Clinic in Berlin were questioned, to compare their knowledge and opinion on menopause and possible cultural influence factors. The results showed that 70% of the migrant vs. 90% of the German women regarded menopause as a normal phase in a women's life and more Turkish than German women (35% vs. 7%) associated complaints with menopause. However the immigrant women knew noticeably less about health risks related to menopause (10% vs. 50%).

Adult↗
PubMed2001

[Comparison between anterior rhinomanometry and impulse-oscillometric rhinometry found within nasal allergen provocation].

UNLABELLED: Besides the standard method of anterior rhinomanometry (aR), the impulse-oscillometric rhinometry (IOS) is available for measurements of the nasal resistance. The aR is a procedure dependent on the cooperation of the patient, whereas IOS is measured regardless from the breathing activities of the patient. We examined weather the resistance-measurement by means of IOS in comparison to the aR is a more suitable method for nasal allergic provocation. METHOD: 17 patients with anamnestic known rhinokonjunktivitis (6 f, 11 m) had a pricktest and then a nasal provocation testing with an allergen which provoked a reaction on the skin. The complete resistance of the nose was measured in a randomized order by means of aR and IOS. RESULTS: The complete resistance showed neither in the basic measurement (aR 0,38 +/- 0,14 kPa/l/s; IOS 0,38 +/- 0,11 kPa/l/s) nor in the control solution (aR 0,38 +/- 0,14; IOS 0,39 +/- 0,14) nor after application of the allergenic solution (15 min: aR 0,69 +/- 0,27; IOS 0,77 +/- 0,42; 30 min: aR 0,65 +/- 0,29; IOS 0,6 +/- 0,38) a significant difference between the two methods. The results of the measurement of aR and IOS after the allergenic solution showed a positive correlation (15 min: r = 0,63, p < 0,01; 30 min: r = 0,67, p < 0,01). We found by means of clinic and measurement methods in the aR of 7 patients a positive reaction, within 7 patient a negative reaction, 3 patients had a unspecific nasal hyperreactivity. There was a correspondence in 6 of the 7 patients with positive reaction in aR between both methods. 4 of the 7 results with negative reaction in the aR would have been positive then underlying the same criteria in the IOS without announcing the symptomscore a relevant clinical symptomatic while testing. CONCLUSION: IOS is a suitable procedure for nasal provocation testing and provides results similar to the aR. In comparison to aR IOS is not dependent on the patients cooperation. Due to its higher sensitivity the valid limits of the aR at provocation testings cannot be transferred to IOS to avoid a false positive reaction.

Adult↗
PubMed2001

Breast-feeding and the onset of atopic dermatitis in childhood: a systematic review and meta-analysis of prospective studies.

BACKGROUND: Despite the numerous studies on the possible protective effect of breast-feeding against the onset of atopic dermatitis during childhood, this issue remains controversial. OBJECTIVE: We conducted a systematic review with meta-analysis of prospective studies that evaluated the association between exclusive breast-feeding during the first 3 months after birth and atopic dermatitis. METHODS: A comprehensive search of the 1966-2000 MEDLINE database and review of the reference lists of relevant articles identified 18 prospective studies that met the predefined inclusion criteria. By means of a standardized approach, 2 of the investigators independently assessed the methodologic quality of the studies, duration and exclusivity of breast-feeding, outcome measures, and control for potential confounding factors. The same approach was applied during data abstraction and evaluation of the estimates of association. Summary measures of association were then calculated. RESULTS: The summary odds ratio (OR) for the protective effect of breast-feeding in the studies analyzed was 0.68 (95% confidence interval [CI], 0.52-0.88). This effect estimate was higher in the group of studies wherein children with a family history of atopy were investigated separately (OR = 0.58; CI, 0.41-0.92) than in those of combined populations (OR = 0.84; CI, 0.59-1.19). A small subset of studies of children without a history of atopy in first-degree relatives showed no association between breast-feeding and the onset of atopic dermatitis (OR = 1.43; CI, 0.72-2.86). CONCLUSION: Exclusive breast-feeding during the first 3 months of life is associated with lower incidence rates of atopic dermatitis during childhood in children with a family history of atopy. This effect is lessened in the general population and negligible in children without first-order atopic relatives. Breast-feeding should be strongly recommended to mothers of infants with a family history of atopy, as a possible means of preventing atopic eczema.

Breast Feeding↗