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Biomedical subjects

K Fritz

Publications and source records attributed to K Fritz.

At least 19 recordsLinked to original sources
PubMed2006

[The role played by calcium in neuronal injury following neonatal hypoxia or convulsions].

AIM: Calcium plays a complex and pivotal role both in neuronal development and function, and in hypoxia/ ischemia-induced cell death. In this paper, we review current concepts of calcium function emphasizing the neonatal period. DEVELOPMENT: Calcium enters the neuron through glutamate receptors (NMDA and AMPA) located on the neuronal membrane. After hypoxia or seizures, there is a conformational change of the receptors, with increased flow of calcium into the cytoplasm. Cytoplasmatic calcium triggers activation of several free-radical generation pathways, including the nitric oxide pathway, with a deleterious effect upon the neuron. Calcium then enters the neuronal nucleus, through specific receptors on the nuclear membrane. In our experience, hypoxia and neonatal seizures create nuclear membrane dysfunction, increasing the nitric-oxide-dependent flow of calcium into the nucleus. Nuclear calcium increase is critical for genetic transcription, pro-apoptotic gene activation and a cascade of biochemical and molecular events that lead to an increase of caspases and apoptotic neuronal death. CONCLUSIONS: Calcium has a crucial role in neuronal damage after neonatal hypoxia or seizures. A better knowledge of the pathogenic mechanisms that lead to neuronal damage after neonatal hypoxia or seizures will assist in future development of efficacious neuroprotective therapies.

Calcium↗
PubMed2001

Expression of Bax and Bcl-2 proteins during hypoxia in cerebral cortical neuronal nuclei of newborn piglets: effect of administration of magnesium sulfate.

This study tests the hypothesis that administration of magnesium sulfate, an antagonist of the NMDA receptor ion-channel, will prevent the hypoxia-induced alteration in the expression and the ratio of Bax and Bcl-2 proteins in cerebral cortical neuronal nuclear membranes. Anesthetized, ventilated and instrumented newborn piglets were divided into three groups: normoxic controls (Nx), untreated hypoxic (Hx), and magnesium sulfate-treated hypoxic (Mg-Hx) groups. Cerebral hypoxia was induced by lowering the FiO2 (0.05-0.07) for 1 h and the cerebral cortex was harvested immediately for isolation of neuronal nuclei and hypoxia was confirmed biochemically by a decrease in the tissue levels of ATP and phosphocreatine (PCr). Brain tissue PCr (micromol/g brain) was 2.74+/-0.77 (Nx), 0.38+/-0.09 (Hx, P<0.05 vs. Nx) and 0.69+/-0.60 (Mg-Hx, P<0.05 vs. Nx). The density of immunoblotted proteins was expressed as absorbance (Axmm(2)). The expression of Bax protein (Axmm(2)) was 222+/-31 (Nx), 279+/-32 (Hx), and 148+/-44 (Mg-Hx, P<0.05 vs. Hx). Bcl-2 protein expression was 77+/-1.0 (Nx), 37+/-5.0 (Hx) and 46+/-15 (Mg-Hx, P<0.05 vs. Nx). The ratio of Bax to Bcl-2 proteins increased more than twofold during hypoxia as compared to normoxia (7:1 Hx vs. 3:1 Nx). However, in the magnesium sulfate-treated group the Bax:Bcl-2 ratio was similar to normoxic controls. The data demonstrate that magnesium sulfate treatment prevents both the hypoxia-induced increase in Bax protein expression and the alteration of Bax:Bcl-2 protein ratios. We suggest that magnesium sulfate treatment before and during hypoxia may decrease hypoxia-induced programmed cell death by maintaining the normal ratio of Bax to Bcl-2 proteins.

Adenosine Triphosphate↗
PubMed2000

["Open approach"--"progress" back the beginnings of septorhinoplasty].

Looking back at 150 years of the development of septorhinoplasty--50 of which I have experienced myself--one can conclude that recent developments go back to the nineteenth century. In the era of "minimal invasive surgery" the "open approach" to septorhinoplasty should no longer be indicated. The sublabial approach in the sense of minimal invasive surgery is recommended.

Endoscopy↗
PubMed1997

[Juvenile Adamantiades-Behçet disease in decreased stimulation with anti-CD3 monoclonal antibody].

A 12 year old boy developed the complete symptom complex of Adamantiades-Behçet's disease over a two-year period. He presented with the mucocutaneous variant with recurrent to persistent oral ulcers which extended into the pharynx, recurrent genital ulcers, perianal lesions, and a positive pathergy test. Ocular involvement and other symptoms associated with the disease were absent. However, the early onset of the disease and the male gender indicated a bad prognosis. The patients father deficiency of suffered from bronchial asthma with recurrent respiratory infections. An IgG-3 subclass was detected. Lymphocyte transformation tests showed markedly diminished response to stimulation with anti-CD3 monoclonal antibody in both patients, while response to PWM, CoA and PHA was normal. In addition, the concentration of serum soluble interleukin 6 receptor was reduced in both patients.

Antibodies, Monoclonal↗
PubMed1997

Compiling a placement audit tool: a case study of one college's use of the QualCube model in developing an audit tool for student placement areas.

Nursing students, as users of college services, can rightly expect satisfaction and even continuous improvement in their clinical experience, which is one of the cornerstones of nurse education. The North Yorkshire College of Health Studies has developed and used a multidisciplinary placement audit tool based on QualCube, a framework for standard setting, auditing and improving quality developed by Nicklin and Lankshear (in Nicklin & Kenworthy 1995 p 18). In order to facilitate a thorough audit of placement areas, a working group devised the tool based on the relevant areas of intersection of the three planes of the cube and then set written standards and specified performance criteria. This article describes the application of the QualCube framework, the design and description of the tool and feedback on its usage. The exciting and useful difference in the tool is its final page, the action plan, which is designed to realistically encourage continuous improvement in each placement area.

Education, Nursing, Baccalaureate↗
PubMed1997

Epidemiological features of Adamantiades-Behçet's disease in Germany and in Europe.

The German Registry of Adamantiades-Behçet's disease was founded in 1990 in Berlin and it provides current data on the epidemiology, the clinical manifestations and the course of the disease in Germany on a continuous basis. A total of 218 patients, including 89 German and 100 Turkish patients, had been reported to the German Registry until October 1997. One hundred and ninety-six patients fulfilled the criteria of the Behçet's disease classification tree. The prevalence of the disease evaluated in Berlin-West was 1.68/100,000 in 1989 and had risen to 2.26/100,000 by 1994. The median age of onset was 25 years (range 5 to 66 years; German-Turks, ns). Juvenile disease was recorded in 6.9% of patients. The complete clinical picture according to the criteria of the International Study Group of Behçet's Disease developed in 15.5 months. The interval between onset of the disease and diagnosis was 35 months, which was significantly longer than the duration of the development of the complete clinical picture (p < 0.0001). The disease was diagnosed later in German (48.5 months) than in Turkish patients (25.5 months, p = 0.003). While German patients presented an equal male-to-female ratio, a male predominance was shown in Turkish patients (M:F 2.1:1, p = 0.022). Familial occurrence was detected in 2.0% of German and 15.9% of Turkish patients (p = 0.013). The frequencies of major clinical manifestations were: oral ulcers 99%, skin lesions 76%, genital ulcers 75%, ocular manifestations 59%, arthritis 59%, and positive pathergy test 52%. Clinical differences between German and Turkish patients were only found in the frequency of ocular lesions (48% vs. 66%, p = 0.025). Oral ulcers were with 72% the most common onset symptom of the disease followed by erythema nodosum (9%), uveitis (7%), arthritis (7%), genital ulcers (3%), superficial thrombophlebitis (2%) and papules/sterile pustules (2%). Uveitis and erythema nodosum as onset symptoms shortened the median interval to diagnosis to 1.5 and 15 months, respectively, while arthritis delayed diagnosis (43.5 months; p = 0.029). A severe course developed in 25% of the patients; irreversible retinal vasculitis to blindness in 15%, sterile meningoencephalitis in 8%, severe arthritis in 5%, hemoptysis in 2%, lethal outcome in 2% and bowel perforation in 1%. The relative risk of HLA-B5 positive German natives developing the disease. HLA-B5 was confirmed as a marker of severe prognosis. Cardiolipin autoantibodies were associated with cutaneous vasculitis and superficial thrombophlebitis was correlated with systemic vessel involvement.

Adolescent↗
PubMed1995

Chronic relapsing pancreatitis from a scorpion sting in Trinidad.

Chronic relapsing pancreatitis is a rare cause of abdominal pain in children and exceptionally rarely is related to a scorpion sting. We describe a 13-year-old girl who, following envenoming by a scorpion, developed recurrent attacks of sharp, intermittent pain in the umbilical region associated with fever, nausea, anorexia and vomiting, and changes in her psychological behaviour. Thorough clinical evaluation, including CT scanning, disclosed unabated pancreatitis. A modified Puestow procedure was performed with very good results. Physicians should be aware that in chronic relapsing pancreatitis, particularly in children, a scorpion sting should be considered an aetiological possibility.

Abdominal Pain↗
PubMed1994

Pilocarpine-induced lysosomal enzyme secretion, from bovine trabecular meshwork cells.

It has long been held that pilocarpine-induced ciliary muscle contraction causes a mechanical change in the configuration of the trabecular meshwork, thereby increasing its fluid conductance. Though the results of many studies are consistent with this theory, other findings suggest a direct action of pilocarpine on the meshwork. We used cultured bovine trabecular meshwork (BTM) cells to study the cell biological effects of pilocarpine, chemically a weak base, and demonstrated increased vacuolization of the BTM cells after incubation with pilocarpine, reflecting a trapping of the protonated base inside the lysosomes. We also showed that pilocarpine enhanced the release of lysosomal hydrolases into the medium. We hypothesize that this is clinically relevant and that the pilocarpine-induced release of hydrolases modifies the extracellular matrix of the trabecular meshwork, thereby increasing its fluid conductance.

Animals↗
PubMed1992

Delayed presentation of congenital diaphragmatic hernia.

Eight patients aged 1 month up to nine years with congenital diaphragmatic hernias (seven left sided postero-lateral, one right-sided antero-medial), who presented outside of the neonatal period, are reported, four are described in detail. Radiographic presentation was obvious in four patients, simulated inflammatory lung disease in one and pneumothorax in two. In one patient a Morgagni hernia was primarily missed. Two had previous normal chest X-rays. All cases with herniated bowel showed "connecting" bowel segments passing through the diaphragmatic defect. Primarily the lack of awareness of delayed presentation of congenital diaphragmatic hernia in children with uncharacteristic thoracic and/or abdominal symptoms led to an undesirable time delay between first chest X-ray and surgery up to 16 months in four of our cases. Life threatening complications can be the consequence of delayed diagnosis as in one of our cases.

Child↗