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Biomedical subjects

G Hammer

Publications and source records attributed to G Hammer.

17 recordsLinked to original sources
PubMed2006

[Quantification of pulmonary emphysema in multislice-CT using different software tools].

PURPOSE: The data records of thin-section MSCT of the lung with approx. 300 images are difficult to use in manual evaluation. A computer-assisted pre-diagnosis can help with reporting. Furthermore, post-processing techniques, for instance, for quantification of emphysema on the basis of three-dimensional anatomical information might be improved and the workflow might be further automated. MATERIALS AND METHODS: The results of 4 programs (Pulmo, Volume, YACTA and PulmoFUNC) for the quantitative analysis of emphysema (lung and emphysema volume, mean lung density and emphysema index) of 30 consecutive thin-section MSCT datasets with different emphysema severity levels were compared. The classification result of the YACTA program for different types of emphysema was also analyzed. RESULTS: Pulmo and Volume have a median operating time of 105 and 59 minutes respectively due to the necessity for extensive manual correction of the lung segmentation. The programs PulmoFUNC and YACTA, which are automated to a large extent, have a median runtime of 26 and 16 minutes, respectively. The evaluation with Pulmo and Volume using 2 different datasets resulted in implausible values. PulmoFUNC crashed with 2 other datasets in a reproducible manner. Only with YACTA could all graphic datasets be evaluated. The lung volume, emphysema volume, emphysema index and mean lung density determined by YACTA and PulmoFUNC are significantly larger than the corresponding values of Volume and Pulmo (differences: Volume: 119 cm(3)/65 cm(3)/1 %/17 HU, Pulmo: 60 cm(3)/96 cm(3)/1 %/37 HU). Classification of the emphysema type was in agreement with that of the radiologist in 26 panlobular cases, in 22 paraseptalen cases and in 15 centrilobular emphysema cases. CONCLUSION: The substantial expenditure of time obstructs the employment of quantitative emphysema analysis in the clinical routine. The results of YACTA and PulmoFUNC are affected by the dedicated exclusion of the tracheobronchial system. These fully automatic tools enable not only fast quantification without manual interaction, but also a reproducible measurement without user dependence.

Adolescent↗
PubMed1997

Localization of language cortices by functional MR imaging compared with intracarotid amobarbital hemispheric sedation.

OBJECTIVE: We undertook this study to investigate functional MR imaging as a new clinical method for determining hemispheric language dominance. Seven patients undergoing surgical evaluation for chronic intractable epilepsy were studied. Intracarotid amobarbital injection was also performed and the findings compared with the functional MR imaging results. CONCLUSION: Functional MR imaging studies enabled localization of the frontal and temporal lobe language cortices. The results of functional MR imaging and intracarotid amobarbital testing of hemispheric language dominance agreed in all seven patients, including two right-handed patients with right-hemisphere language dominance. These preliminary results show that functional MR imaging is an accurate noninvasive method of determining language dominance that may replace the amobarbital test for some purposes if confirmed by additional research.

Adult↗
PubMed1994

Pseudomonas aeruginosa bacteremia in patients with AIDS.

Twenty-seven episodes of Pseudomonas aeruginosa bacteremia in 21 patients with AIDS were evaluated at the Mount Sinai Medical Center in 1987-1992. Of 21 primary episodes, 12 were acquired in the community, 8 were nosocomial, and one was acquired in a nursing home. Sources of bacteremia (i.e., sites of infection; n = 30) included the lungs (12 cases) an indwelling vascular catheter (9), and the upper respiratory tract (5, including 2 cases of sinusitis, 2 cases of malignant external otitis, and 1 case of epiglottis/pharyngeal cellulitis); in 4 cases the source was unknown. White blood cell counts ranged from 0.1 to 26.2 (mean, 4.32) x 10(3)/mm3; in 19 of 26 cases, the absolute neutrophil count was > 1 x 10(3)/mm3. With the exclusion of primary episodes of bacteremia that resulted in death, the rate of relapse was 33.3% (5 of 15 cases). Mortality for the 25 evaluable episodes of bacteremia was 40% (32% for primary infection and 80% for relapse; P = .06); 52.6% of evaluable patients (10 of 19) ultimately died of P. aeruginosa bacteremia. The institution of appropriate therapy at presentation did not positively affect outcome. Rates of response were higher among episodes treated with a drug combination (an antipseudomonal beta-lactam or monobactam antibiotic plus an aminoglycoside) than among those treated with a single agent (P = .036).

AIDS-Related Opportunistic Infections↗
PubMed1993

Intramuscular pentamidine for the prevention of Pneumocystis carinii pneumonia in patients infected with human immunodeficiency virus.

We retrospectively reviewed the charts of 96 patients infected with human immunodeficiency virus (HIV) who received intramuscular pentamidine for the prevention of Pneumocystis carinii pneumonia (PCP). These patients, all of whom had either a history of PCP or a CD4 lymphocyte count of < or = 0.2 x 10(9)/L, were intolerant of sulfa drugs, neutropenic, or intolerant of aerosolized treatment. Intramuscular pentamidine was given monthly by the Z-track technique at a dosage of 300 mg (4 mg/kg if the patient weighed < 50 kg). During a total of 350 months of primary prophylaxis in 47 patients and 426 months of secondary prophylaxis in 49 patients, only three cases of PCP occurred. More than 73% of the patients were receiving zidovudine concomitantly. Adverse reactions to intramuscular pentamidine included two episodes of hypotension, three of sterile abscess, two of glucose intolerance, and one of asymptomatic hypoglycemia. The administration of intramuscular pentamidine by the Z-track technique for PCP prophylaxis appears to be highly effective and minimally toxic.

AIDS-Related Opportunistic Infections↗
PubMed1991

Enteric neural modulation of slow-wave activity in cat colon.

These studies test the hypothesis that the generation of colonic slow waves can be modulated by stimulation of intrinsic enteric nerves and attempt to identify a neurotransmitter that may be responsible for this change in slow-wave activity. Isolated segments from the mid-colon of the cat generated regular, continuous slow waves at 6.5 +/- 1.1 cpm. Activation of the intrinsic nerves by electrical field stimulation transiently reduced the rate of slow-wave generation to 4.7 +/- 0.7 cpm (P less than 0.001). The response to electrical stimulation was blocked by tetrodotoxin and alpha-chymotrypsin. The following antagonists were not effective in blocking the response: atropine, hexamethonium, phenoxybenzamine, propranolol, methysergide, naloxone, or imidazole. Vasoactive intestinal polypeptide (5 x 10(-7) M) decreased slow wave frequency to 4.5 +/- 0.4 cpm. Vasoactive intestinal polypeptide (VIP) fragment 10-28 inhibited the effect of electrical field stimulation but also decreased the slow-wave frequency. VIP-immunoreactive nerves were much more abundant in the plexus submucosus extremus than in the circular muscle of the muscularis externa. Thus, pacemakers for colonic slow waves may be modulated by intrinsic colonic nerves, and vasoactive intestinal polypeptide may be the neurotransmitter responsible for this modulation.

Animals↗
PubMed1990

Separation by carrier-free electrophoresis of subpopulations of bovine alveolar macrophages.

Carrier-free electrophoresis was used to separate subpopulations of bovine alveolar macrophages according to their electrical surface charges. The electrophoretic mobility of the macrophages changed significantly as a function of the time of cultivation in vitro. After 20 h, three subgroups were identified which differed in their specific contents of lysosomal hydrolases, alpha-naphthyl acetate esterase, and alkaline phosphodiesterase. By comparing the findings with results from the literature it was concluded that the subgroups correspond to different stages of maturation and that the fraction moving fastest may be the most mature fraction. The results were not influenced by phagocytosis and the presence or absence of Ca2+.

Animals↗
PubMed1986

[Clinical aspects of progressive systemic scleroderma (PSS). Multicenter studies of 194 patients].

Patients from five German Departments of Dermatology (Düsseldorf, Erlangen, Frankfurt am Main, Hamburg and Munich) affected with progressive systemic scleroderma (PSS) were classified and examined. The results of the clinical investigations are presented. In order to guarantee a uniform classification of all patients, the patients were divided into three groups according to the distribution of the affected skin: type I consisted of those with acrosclerosis distal to the wrist, type II had scleroderma extending along the wrist in a proximal direction, and type III had diffuse scleroderma beginning on the trunk. Altogether, 194 patients with PSS were investigated, and the following distribution was found: type I, 32%; type II, 60%; type III, 7%; 1% of the patients could not be classified. The distribution according to the patients' sex and age was in good agreement with published reference data. The incidence, significance, and localization of the major symptoms were investigated. The Raynaud symptom could be identified as being the main clinical symptom in 90% of the patients. Joint involvements (10%-73% depending in the applied parameters), dysphagia (51%), and rest dyspnea (30%) contributed to the main internal symptoms. The extensive clinical, chemical, and immunological results are summarized. In 80% of the cases, high ANA titers could be detected, but these were not correlated to the type of disease.

Adult↗
PubMed1984

[Dowling-Degos disease].

On the basis of a case report, we discuss diagnosis and differential diagnosis of Dowling Degos disease. Of special importance seems to be differentiation from acanthosis nigricans, because the patients may be saved straining and expensive clinical examination.

Adult↗
PubMed1983

Porphyria cutanea tarda and pregnancy.

A female patient with porphyria cutanea tarda (PCT) clinically cured by a low-dose chloroquine treatment showed neither exacerbation of the disease nor an increased excretion of urinary porphyrins during pregnancy. The role of estrogens and gestagens as clinical manifestation factors of PCT is discussed. According to our observation the porphyrogenic effect of the estrogens seems to have been overestimated.

Adult↗
PubMed1978

Antibacterial functions of macrophages in experimental protein-calorie malnutrition. II. Cellular and humoral factors for chemotaxis, phagocytosis, and intracellular bactericidal activity.

Cellular and humoral aspects of the antibacterial activity of macrophages during experimental protein-calorie malnutrition were studied. There were no defects in chemotaxis or bactericidal activity of cells from protein-deficient animals, although phagocytosis-associated oxygen consumption and hexose monophosphate shunt activity were depressed. However, marked impairment of humoral chemotactic factors generated in the peritoneal cavity by glycogen injection and of heatlabile serum opsonins for Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Salmonella enteritidis was found. The studies suggested that some macrophage antibacterial functions measured in vitro are not altered in experimental acute protein-calorie malnutrition, but that serum factors, presumably complement-derived, would limit their in vivo function. Thymic involution and lymphocyte depletion would further impair in vivo cellular immune reactions affected by macrophages. This model may therefore prove useful for the study of specific aspects of cellular immunity in malnourished hosts and of specific rehabilitation strategies.

Animals↗