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Biomedical subjects

J Starke

Publications and source records attributed to J Starke.

16 recordsLinked to original sources
PubMed2006

The influence of PEEP and tidal volume on central blood volume.

BACKGROUND AND OBJECTIVE: Measurement of central blood volumes (CBV), such as global end-diastolic volume (GEDV) and right ventricular end-diastolic volume (RVEDV) are considered appropriate estimates of intravascular volume status. However, to apply those parameters for preload assessment in mechanically ventilated patients, the influence of tidal volume (TV) and positive endexpiratory airway pressure (PEEP) on those parameters must be known. METHODS: In 13 mechanically ventilated piglets, the effect of low (10 mL kg(-1)) and high (20 mL kg(-1)) TVs on CBV was investigated in absence and presence of PEEP (0 and 15 cm H(2)O). GEDV, RVEDV, right heart (RHEDV) and left heart end-diastolic volume (LHEDV) were measured by thermodilution. Blood flow on the descending thoracic aorta measured with an ultrasonic flow-probe served to determine stroke volume (SV). Measurements were performed during baseline conditions, after volume loading with previously extracted haemodilution blood (20 mL kg(-1)) and following haemorrhage (30 mL kg(-1)). RESULTS: Application of PEEP decreased GEDV and SV significantly (P < 0.05). Augmenting TV did not reduce GEDV systematically, but significantly reduced SV (P < 0.05). Changes in ventilator settings only influenced RVEDV following volume loading (P < 0.05). RHEDV and LHEDV decreased following application of PEEP, but only RHEDV decreased after augmenting TV at baseline and following volume loading. Correlation of SV with parameters of CBV was r = 0.487 (P < 0.01) for GEDV, r = 0.553 (P < 0.01) for RVEDV, r = 0.596 (P < 0.01) for RHEDV and r = 0.303 (P < 0.01) for LHEDV. CONCLUSION: Application of PEEP decreases CBV and SV. Augmenting TV reduces SV but not CBV. There is a moderate correlation between parameters of CBV and cardiac performance.

Animals↗
PubMed2005

Model of calcium oscillations due to negative feedback in olfactory cilia.

We present a mathematical model for calcium oscillations in the cilia of olfactory sensory neurons. The underlying mechanism is based on direct negative regulation of cyclic nucleotide-gated channels by calcium/calmodulin and does not require any autocatalysis such as calcium-induced calcium release. The model is in quantitative agreement with available experimental data, both with respect to oscillations and to fast adaptation. We give predictions for the ranges of parameters in which oscillations should be observable. Relevance of the model to calcium oscillations in other systems is discussed.

Animals↗
PubMed2005

Analysis and visualization of growth-related and treatment-induced craniofacial changes.

An analysis and visualization of craniofacial shape changes due to growth or orthodontic treatment is presented. The suggested method is based on an adapted Karhunen-Loève decomposition of time-discrete data based on landmarks in lateral X-rays of the skull. It allows for a reduction of the high-dimensional dynamic problem to a few spatial modes representing synchronous components of growth patterns with time-dependent mode coefficients. The growth-related shape changes as well as the orthodontic treatment effects are visualized by overdrawing the underlying shape changes. The results based on this technique give insight into the still controversially discussed question to which degree the craniofacial skeletal structures can be influenced by orthodontic appliances.

Child↗
PubMed2001

Effects of early activator treatment in patients with class II malocclusion evaluated by thin-plate spline analysis.

The aim of the present longitudinal cephalometric study was to evaluate the dentofacial shape changes induced by activator treatment between 9.5 and 11.5 years in male Class II patients. For a rigorous morphometric analysis, a thin-plate spline analysis was performed to assess and visualize dental and skeletal craniofacial changes. Twenty male patients with a skeletal Class II malrelationship and increased overjet who had been treated at the University of Heidelberg with a modified Andresen-Häupl-type activator were compared with a control group of 15 untreated male subjects of the Belfast Growth Study. The shape changes for each group were visualized on thin-plate splines with one spline comprising all 13 landmarks to show all the craniofacial shape changes, including skeletal and dento-alveolar reactions, and a second spline based on 7 landmarks to visualize only the skeletal changes. In the activator group, the grid deformation of the total spline pointed to a strong activator-induced reduction of the overjet that was caused both by a tipping of the incisors and by a moderation of sagittal discrepancies, particularly a slight advancement of the mandible. In contrast with this, in the control group, only slight localized shape changes could be detected. Both in the 7- and 13-landmark configurations, the shape changes between the groups differed significantly at P < .001. In the present study, the morphometric approach of thin-plate spline analysis turned out to be a useful morphometric supplement to conventional cephalometrics because the complex patterns of shape change could be suggestively visualized.

Activator Appliances↗
PubMed1995

The surgical implications of chronic granulomatous disease.

BACKGROUND: Chronic granulomatous disease (CGD) of childhood is a rare congenital abnormality of the phagocyte NADPH oxidase system. Affected neutrophils and macrophages have an ineffective respiratory burst and cannot destroy certain phagocytized bacteria and fungi. CGD patients usually present with recurrent pyogenic and fungal infections. Catalase-positive bacteria are frequently involved, since they metabolize the hydrogen peroxide they produce, making it unavailable for augmentation of microbicidal activity in CGD neutrophils. Afflicted patients also have a tendency to form granulomas, which can lead to obstruction of the gastrointestinal and genitourinary tracts. METHODS: Charts of 10 patients with CGD were reviewed for age at diagnosis, surgical procedures, complications of these procedures, and medical treatment. RESULTS: Eight of the 10 children were male. The average age at first presentation was 18 months (range 2 days to 9.8 years). Each child developed a mean of 9.9 infections and an average of 1.4 infections per year. All required surgical procedures, with an average of 2.9 procedures each. Five children had operative procedures for infections that preceded the diagnosis of CGD. The procedures performed most frequently were incision and drainage of soft-tissue abcesses (7) or perirectal abscess (3), thoracentesis (3), and bronchoscopy (3). Three children had poor wound healing following surgery. Two developed partial gastric outlet obstruction which resolved with antibiotic therapy. One developed granulomatous cystitis with obstruction which responded to antibiotics. CONCLUSIONS: Since patients with undiagnosed CGD may present with surgical problems, surgeons need to be familiar with this condition. The diagnosis should be suspected in children who have recurrent or unusual infections or unexplained problems with wound healing.

Child↗
PubMed1994

Analysis of the involvement of ocs-like bZip-binding elements in the differential strength of the bidirectional mas1'2' promoter.

The ocs-like elements of the bidirectional mas1'2' promoter of Agrobacterium tumefaciens, mas1' and mas2', were analyzed to elucidate their role in the expression conferred by this promoter. Tetramers of the elements were cloned upstream of the beta-glucuronidase-coding region linked to the 35S promoter deleted at -54. Transient expression assays with tobacco (Nicotiana tabacum) and potato (Solanum tuberosum) protoplasts showed that tetramers of the mas1' element had 3- to 8-fold enhancing activity, respectively. Enhancement obtained by tetramers of the mas2' element was higher, suggesting that this element plays a role in the stronger promoter activity from the 2' side. Three cDNA clones with higher homology to the tobacco transcription factor TGA1a were isolated from a potato root expression library. Overexpression of the proteins encoded by these cDNA clones in Escherichia coli and analysis of DNA-binding activity in bacterial extracts showed that all three factors could bind strongly to the mas1' ocs-like element. In contrast, only two of the mas-binding factors exhibited significant binding to the mas2' element. Southern analysis revealed the presence of a small, multigene family encoding the mas-binding factors in potato.

Agrobacterium tumefaciens↗
PubMed1993

Primary adenocarcinoma arising in an ileostomy.

Two cases are added to the world literature of patients in whom an adenocarcinoma developed at the ileostomy site after total proctocolectomy for ulcerative colitis. Fourteen additional cases have been reported in the world literature; of these, 12 cases have been in patients with ulcerative colitis, and four cases have been in patients with familial adenomatous polyposis. Adenocarcinoma of an ileostomy is not common. However, in the analysis of the reported cases, patients with long-standing ileostomies appear to be at a greater risk. With an aging ileostomy population, an increase in the number of cases may be seen. Three hypotheses are discussed as potential causative pathways to this entity. Continued analysis of these cases may yield information on the pathophysiology involved.

Adenocarcinoma↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment and prevention of tuberculosis. Infectious Diseases Society of America and the Food and Drug Administration.

This guideline addresses the evaluation of new antimycobacterial drugs in the treatment and prevention (secondary prophylaxis) of infection by M. tuberculosis. Patients may be enrolled in clinical trials on the basis of clinical and/or microbiological criteria. A therapeutic regimen will likely include a combination of drugs; a randomized, active-control, comparative clinical trial is recommended. If appropriate samples can be obtained for culture during follow-up without placing the patient at unwarranted risk, the assessment of microbiological outcome is paramount. Prophylaxis will probably require a single drug, and a similar study design is preferred.

Adult↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment and prevention of infections caused by the Mycobacterium avium complex. Infectious Diseases Society of America and the Food and Drug Administration.

The bacteria of the Mycobacterium avium complex are ubiquitous; thus it is often difficult to distinguish environmental contamination from colonization or infection. Patients with either pulmonary or disseminated infection may be enrolled in clinical trials. Disseminated disease occurs mostly in patients infected with the human immunodeficiency virus. In general, a randomized, active-control, double-blinded clinical trial is preferred; there should at least be a blinded evaluator. With regard to immunosuppressed populations, new antimycobacterial drugs need to be evaluated not only for the treatment but also for the prevention of disease. For trials of prophylaxis a placebo-controlled design is ethical until a drug is proven effective; then the use of an active-control regimen is appropriate. Since no regimen has been approved by the U.S. Food and Drug Administration for treatment or prevention of disease caused by the M. avium complex, demonstration of the superiority of the study regimen to the control regimen should be the objective of the clinical trial.

Anti-Bacterial Agents↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of disease caused by Mycobacterium kansasii and other mycobacteria. Infectious Diseases Society of America and the Food and Drug Administration.

Mycobacterium kansasii is a photochromogenic nontuberculous mycobacterium that usually causes infections of the respiratory tract in humans. Although spontaneous resolution of infection has been reported, most patients require antimycobacterial therapy. A three- or four-drug combination--isoniazid, rifampin, and ethambutol and/or streptomycin--usually is prescribed. For evaluation of a new drug, a randomized, double-blind or evaluator-blinded, active-control comparative study design is recommended. Treatment should continue for 18-24 months, and follow-up evaluations should be conducted every 6 months for 3 years. Microbiological outcome is paramount.

Anti-Infective Agents↗
PubMed1992

[Transposition of the gluteus maximus muscle for sphincter replacement in anal incontinence].

The replacement of the external anal sphincter by gluteus muscle in fecal incontinence is described in 4 cases. All patients, three children and one adult, had been operated on previously because of different types of anal atresia and suffered from fecal incontinence grade IV. They all showed a congenital defect of the somatic sphincter. The absent external and sphincter muscle was repaired by transposing innervated and vascularized gluteus muscle. In all cases active anal continence was achieved proven by clinical and electromanometric measures. The results, compared to other techniques, are discussed.

Adult↗
PubMedDate not supplied

Follicular carcinoma of the thyroid.

Follicular carcinoma deserves a careful preoperative evaluation and multidisciplinary therapy planning. Needle aspiration may be of less value than for other thyroid lesions. If the surgeon is suspicious of a carcinoma, a total lobectomy of the involved side and frozen section may be indicated. Lobectomy with or without isthmusectomy seems to be the minimal treatment for tumors confined to the lobe without nodal metastases. Total thyroidectomy is reserved for patients at high risk by nature of age, large lesions, angioinvasion, capsular invasion, or known metastatic disease where subsequent I-131 therapy is considered likely. I-131 scanning for metastatic disease is indicated in these high-risk patients. I-131 therapy is very valuable for treatment of metastatic disease; and in patients presenting with metastatic disease, total thyroidectomy may be indicated to maximize the therapeutic benefit of the I-131. Judicious planning and care of these patients can result in a 50 to 70% total cure and as high as 85% long-term survival.

Adenocarcinoma↗