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Biomedical subjects

J Blum

Publications and source records attributed to J Blum.

At least 55 records · Page 3Linked to original sources
PubMed2000

The utility of transbronchial needle aspiration in the staging of bronchogenic carcinoma.

We conducted a prospective multi-institutional clinical study involving community hospitals and academic medical centers to more carefully define the value of computerized tomography (CT) of the chest with transbronchial needle aspiration (TBNA) in the staging of bronchogenic carcinoma (CA), and to assess the predictors of a positive aspirate. Of 360 individuals determined to have bronchogenic carcinoma, 50 of 81 (62%) with small cell carcinoma (SCC) and 135 of 279 (48%) with non-small cell carcinoma (NSCC) had positive aspirates (p = 0.034). TBNA precluded additional thoracic surgery in a total of 104 of 360 (29%) patients and was exclusively diagnostic of carcinoma in 65 of 360 (18%) cases. Right-sided tumors were more likely to have a positive mediastinal TBNA (p = 0.002 to 0. 01) as were histologic (67 of 118 [57%]) rather than cytology aspirates (228 of 532 [41%]) (p < 0.001). Sensitivity was > 57% in lymph nodes (LN) >/= 10 mm, and among LN of equivalent size, right paratracheal and subcarinal sites were most likely to establish malignancy. Preoperative CT is a valuable adjunct in the staging of CA by TBNA. Increasing LN size, right-sided tumors, right paratracheal and subcarinal locations, use of a histology needle, and the presence of SCC are the best predictors of a positive aspirate.

Adult↗
PubMed2000

A multicenter trial with a somatostatin analog (99m)Tc depreotide in the evaluation of solitary pulmonary nodules.

OBJECTIVE: The affinity of various malignant neoplasms including small cell and non-small cell lung cancer for peptide analogs of somatostatin has been well documented. Depreotide is such an analog and can be complexed with technetium-99m ((99m)Tc depreotide) for optimal imaging properties. Using this radiopharmaceutical, solitary pulmonary nodules (SPN) were previously evaluated in a successful phase II/III trial. The results of the larger multicenter phase III study using (99m)Tc depreotide to differentiate malignant and benign etiologies in SPN are now presented. METHODS: Patients with SPN </= 6 cm on chest radiograph were referred for evaluation. One hundred fourteen individuals who had an absence of a benign pattern of calcification on CT scan, age > 30 years, and no demonstrable radiographic stability for the prior 2 years were studied. All underwent single-photon emission CT (SPECT) with (99m)Tc depreotide and subsequent tissue histologic examination. Three nuclear medicine specialists blinded to histologic findings examined the SPECT images and scored them as positive or negative based on the presence or absence of activity in the radiographic region of the SPN. The final result was determined by the majority score, which was then compared with the histologic result. RESULTS: Of the 114 individuals studied, 88 had a histologic result compatible with malignant neoplasm. (99m)Tc depreotide scintigraphy correctly identified 85 of this group, with three false-negative determinations compared with histology. There were seven false-positive determinations, including six granulomas and one hamartoma. (99m)Tc depreotide scintigraphy correctly excluded malignancy in 19 of 26 patients with benign histologic findings. The sensitivity of this method was 96.6% with a specificity of 73.1%. CONCLUSION: (99m)Tc depreotide scintigraphy is a safe and useful method for the noninvasive evaluation of SPN with a sensitivity and accuracy comparable to that reported for fluorine-18 fluorodeoxyglucose positron emission tomography.

Aged↗
PubMed1999

[Diagnostic and therapeutic difficulties with tertian malaria].

Diagnosis of malaria tertiana is not uncommonly missed or delayed because of a long incubation period, relapses after an unnoticed primary attack or due to suppressed parasitemia under antibiotics or antimalarials. The presently available rapid tests are not suitable for diagnosis of malaria tertiana. Malaria tertiana acquired in Southeast Asia carries a considerable risk of resistance to chloroquine. In this situation mefloquine is used in first place at total dose of 1000-1500 mg. Relapse of malaria tertiana even after primaquine have been described in travellers returning from the tropics. The efficacy of primaquine can be improved by raising the dose. Hereby an increased risk of hemolysis in concomitant glucose-6-phosphate-dehydrogenase deficiency and, more commonly, gastrointestinal side effects have to be considered.

Humans↗
PubMed1999

Involvement of calyculin A-sensitive phosphatase(s) in the differentiation of Trypanosoma cruzi trypomastigotes to amastigotes.

Differentiation of the non-dividing trypomastigote form of Trypanosoma cruzi, the causative agent of Chagas disease, to the dividing amastigote form normally occurs in cytoplasm of infected cells. Here we show that calyculin A. a potent inhibitor of protein phosphatases 1 and 2A, induces at pH 7.5 extracellular transformation of long slender trypomastigotes to round amastigote-like forms which acquire characteristic features observed after the normal differentiation process: repositioning and structural changes of the kinetoplast, release of surface neuraminidase, and expression of amastigote-specific epitopes. Calyculin A inhibits parasite phosphatases and changes in the phosphorylation of specific proteins occur during the transformation process. As an exposure of trypomastigotes to calyculin A concentrations as low as 1 nM and for only 1-2 h is sufficient to induce transformation, the inhibition of calyculin A-sensitive phosphatase(s) appears to play a major role in initiating the trypomastigote differentiation.

Animals↗
PubMed1999

Differential response of human osteoblast-like cells to commercially pure (cp) titanium grades 1 and 4.

Common dental implants are made of different grades of commercially pure titanium (cpTi) that are more than 99% similar in chemical composition. The objective of this in vitro study was to determine if human osteoblast-like cells, Saos-2, would respond differently when plated on disks of cpTi Grade 1 and Grade 4. Glass disks served as controls. In spite of identical preparation, the two grades of cpTi acquired different surface topographies, as illustrated by scanning electron micrographs and profilometry. Cell responses, such as adhesion, morphology, and collagen synthesis also differed on the two grades of cpTi. Between 4 and 24 h, the rate of cell attachment to Grade 1 differed significantly compared to cell attachment to Grade 4 and to glass. Rhodamine phalloidin fluorescence microscopy showed variations in the actin-based cytoskeleton between grades 1 and 4 cpTi in cell spreading, shape, and the organization of stress fibers. Immunofluorescent staining showed differential expression of vinculin, a focal adhesion protein, on the substrates. At 24 h, the percent of collagen synthesized was significantly more on Grade 1 than on Grade 4 and on glass. Alkaline phosphatase activity was similar on all substrates. The calcium content was significantly higher on Grade 1 than on Grade 4 and on glass at 24 h and at 4 weeks. Thus, commonly used cpTi induced differential morphologic and phenotypic changes in human osteoblast-like cells depending on the grade of the material.

Alkaline Phosphatase↗
PubMed1999

Induction of intracellular arginase activity does not diminish the capacity of macrophages to produce nitric oxide in vitro.

The hypothesis was tested that induction of arginase expression in macrophages (M phi) diminishes nitric oxide (NO) synthesis due to intracellular competition between arginase and inducible nitric oxide synthase (iNOS) for L-arginine (L-arg). Murine M phi cell lines and bone marrow-derived M phi (BMM) were stimulated to express either iNOS or arginase or to co-express these two enzymes. The response pattern obtained was complex but allowed the following conclusions: (i) iNOS and arginase are differentially regulated. (ii) High intracellular arginase levels do not limit the capacity of M phi to synthesize NO even when the L-arg concentration in the culture medium is lowered to physiological levels. (iii) Arginase levels in BMM pre-exposed to either M phi colony-stimulating factor (M-CSF) or granulocyte-M phi colony-stimulating factor (GM-CSF) differ markedly, but iNOS expression and NO synthesis by the two BMM types is similar. (iv) Regulation of iNOS and arginase differs between primary murine bone marrow M phi and murine M phi cell lines. (v) Arginase activity appears to be inhibited during high-output NO synthesis. Taken together, our results show that NO production by M phi is not compromised by conditions that increase intracellular arginase activity.

Animals↗
PubMed1999

Modulation of the inflammatory reaction and neutrophil defense of the bovine lactating mammary gland by growth hormone.

This review is focused on the possible interactions of prolactin and somatotrope hormone in the modulation of inflammation of the mammary gland. Several different models are examined: Escherichia coli, Streptococcus uberis, and endotoxin mastitis. Subsequently, the release of growth hormone and insulin-like growth factor during fever and mastitis, the immunophysiological effects of GH on E. coli mastitis, S. uberis and endotoxin mastitis, the galactopoietic action of rBST on healthy and mastitis cows as well as the immunologic effects of GH on leukocytes in healthy and diseased cows are discussed. It can be concluded that the underlying regulation of the neuro-endocrine network is fundamental in the normal function of the immune system.

Animals↗
PubMed1999

Calculation of the heat-source function in photophoresis of aggregated spheres.

We present theoretical results for the source function in photophoresis of an arbitrary aggregate of spheres that are homogeneous and isotropic piecewise. This source function directly represents the distribution of electric fields inside the spheres. Our calculation is based on a rigorous analytic solution to the radiative multisphere-scattering problem developed recently [Y.-l. Xu, Appl. Opt. 34, 4573 (1995); 36, 9496 (1997); Phys. Lett. A 249, 30 (1998)]. When an aggregate degenerates to a single sphere, the results are exactly the same as those given by the Mie theory. We also discuss the numerical techniques necessary for obtaining an accurate numerical solution for the source function.

Journal Article↗
PubMed1999

Neonatal body composition: dual-energy X-ray absorptiometry, magnetic resonance imaging, and three-dimensional chemical shift imaging versus chemical analysis in piglets.

An animal study to evaluate dual-energy x-ray absorptiometry (DXA) and magnetic resonance (MR) imaging and spectroscopy for measurement of neonatal body composition was performed. Twenty-three piglets with body weights ranging from 848 to 7550 g were used. After measuring total body water, animals were killed and body composition was assessed using DXA and MR (1.5 T; MR imaging, T1-weighted sagittal spin-echo sequence; MR spectroscopy, three-dimensional chemical shift imaging) as well as chemical carcass analysis (standard methods) after homogenization. Body composition by chemical analysis (percent of body weight, mean +/- SD) was as follows: body water, 75.3 +/- 3.9%; total protein, 13.9 +/- 8.8%; and total fat, 6.5 +/- 3.7%. Absolute content of fat and total ash was 7-674 and 35-237 g, respectively. Mean hydration of fat-free mass was 0.804 +/- 0.011 g/kg and decreased with increasing body weight (r2 = 0.419) independent of age. Using DXA, bone mineral content was highly correlated with calcium content (r2 = 0.992), and calcium per bone mineral content was 44.1 +/- 4.2%. DXA fat mass correlated with total fat (r2 = 0.961). Using MR, spectroscopy and chemical analysis were highly correlated with fat-to-water ratio (r2 = 0.984) and absolute fat content (r2 = 0.988). Total fat by MR imaging volumetry showed a lower correlation (r2 = 0.913) and overestimated total fat by a factor of 2.46. Conversion equations for DXA were developed (total fat = 1.31 x fat mass measured by DXA--68.8; calcium = 0.402 x bone mineral content + 1.7), which improved precision and accuracy of DXA measurements. In conclusion, both DXA and MR spectroscopy give accurate and precise estimates of neonatal body composition and may become valuable tools for the noninvasive assessment of neonatal growth and nutritional status.

Absorptiometry, Photon↗
PubMed1999

[Epidemiology and risk factors of cecal dilatation/dislocation and abomasal displacement in dairy cows].

The aims of the study were to determine the prevalence of cecal dilatation/dislocation (CDD) and abomasal displacement (DA) in Switzerland, to identify risk factors for both diseases, and to compare directly their epidemiologic situation. The epidemiologic study included 158 cases of CDD and 149 cases of DA from the cases referred to both University Clinics of Berne and Zurich. The results showed that DA was associated with nutrition-related risk factors: use of minerals and sodium chloride, inadequate concentrate feeding and beginning of the feeding. Furthermore, breed was significantly associated with DA, but not with CDD. Finally, milk yield and pasture were also significantly included in the models. For CDD, nutrition-related risk factors were also found: pasture in summer, use of corn pellets and corn silage in winter. In the final model, protein concentrate was also included. Although both diseases were found at comparable frequencies, the results of this study indicate marked differences between the epidemiology of occurrence of CDD and DA. Therefore, the hypothesis of a common etiopathogenesis appears unlikely.

Animals↗
PubMed1999

Advances in unreamed interlocked nailing of the humeral shaft.

Conservative-functional treatment of fresh humeral shaft fractures remains the method of choice, even though operative stabilization is increasingly being considered as an alternative. Among the surgical options, humeral nailing becomes more and more popular. Different humeral nail systems have been introduced for antegrade implantation. Many of them are criticized as problematic, or even insufficient, because of difficulties in implantation, damage of the humeral head cartilage, shoulder impingement, or rotatory instability.

Journal Article↗
PubMed1998

[Retrograde nailing of humerus shaft fractures with the unreamed humerus nail. An international multicenter study].

Combined with the new unreamed humeral nail (UHN) (Synthes), the retrograde approach to the endomedullary canal of the humeral shaft promises careful reduction and fixation of humeral shaft fractures. This prospective multicenter study reports and analyses 102 retrograde nailings with the UHN and their operative procedures. Seven patients with pathological fractures have died meanwhile, but 75 patients could be followed up until bone healing. Seventy-three fresh humeral shaft fractures, 12 pseudarthrosis, 3 refractures and 14 pathological fractures have been treated with the UHN. In 98 cases (96.1%) the surgeon estimated fracture stability well enough to initiate immediate postoperative elbow and shoulder mobilization. The difficulties involved with free-hand interlocking proximally at the nail tip in 5.9%, fissure or avulsion at the insertion point in 3.9% and radial nerve palsy also in 3.9% of the cases were the most important intraoperative complications. In all 75 patients followed up, bone healing occurred, but five fractures (6.7%) needed more than 8 months connected with a second operative procedure. In one case spongious bone transplantation and new locking bolts had been performed. In three cases a special compression device has been used, whereas in one case also a new nail and in the second spongious bone transplantation had been added. In the fifth case plate osteosynthesis had been performed. At the end of treatment 89.4% of the patients had excellent shoulder function and 88.0% excellent elbow function. Once the indication for surgery is established, the UHN can be considered a reliable and safe implant for stabilizing humeral shaft fractures.

Adolescent↗
PubMed1998

Inhalation anaesthesia for the castration of piglets: CO2 compared to halothane.

General anaesthesia with 80% CO2/20% O2 and 5% halothane in O2 (mask induction) was compared for castration of 3-4 week-old piglets. One group was castrated without anaesthesia. Of the noncastrated control groups one had CO2- and one halothane anaesthesia, one breathed room air through the induction system, and one was held in castration position. The behaviour to induction and castration was assessed, and the cortisol-, ACTH- and beta-endorphin plasma concentrations were determined to quantify the stress elicited by anaesthesia, castration and handling. Violent struggling and vocalization were elicited by CO2 and positioning into the mask induction system while breathing room air; halothane induction was quiet. CO2 induced profound surgical anaesthesia; whereas under halothane anaesthesia some animals exhibited still a slight reaction to castration. Recovery was fast, smooth and quite. Permanent violent struggling and vocalization were elicited by castration without anaesthesia. Plasma cortisol was not a sensitive tool to judge castration stress. The high ACTH and beta-endorphin plasma concentrations elicited by CO2 anaesthesia confirm our clinical experience. General anaesthesia is fast and safely induced with CO2 in piglets and castration can be performed without any reaction, but with CO2 anaesthesia the stress is not reduced.

Anesthesia, Inhalation↗
PubMed1998

Design of an epidemiologic study of drinking water arsenic exposure and skin and bladder cancer risk in a U.S. population.

Ingestion of arsenic-contaminated drinking water is associated with an increased risk of several cancers, including skin and bladder malignancies; but it is not yet clear whether such adverse effects are present at levels to which the U.S. population is exposed. In New Hampshire, detectable levels of arsenic have been reported in drinking water supplies throughout the state. Therefore, we have begun a population-based epidemiologic case-control study in which residents of New Hampshire diagnosed with primary squamous cell (n = 900) and basal cell (n = 1200) skin cancers are being selected from a special statewide skin cancer incidence survey; patients diagnosed with primary bladder cancers (n = 450) are being identified through the New Hampshire State Cancer Registry. Exposure histories of these patients will be compared to a control group of individuals randomly selected from population lists (n = 1200). Along with a detailed personal interview, arsenic and other trace elements are being measured in toenail clipping samples using instrumental neutron activation analysis. Household water samples are being tested on selected participants using a hydride generation technique with high-resolution inductively coupled plasma mass spectrometry. In the first 793 households tested arsenic concentrations ranged from undetectable (0.01 microgram/l) to 180 microgram/l. Over 10% of the private wells contained levels above 10 microgram/l and 2.5% were above 50 microgram/l. Based on our projected sample size, we expect at least 80% power to detect a 2-fold risk of basal cell or squamous cell skin cancer or bladder cancer among individuals with the highest 5% toenail concentrations of arsenic.

Adult↗
PubMed1998

Retrograde nailing of humeral shaft fractures.

The use of intramedullary nailing in the upper extremity is still controversial. Those who have experience with antegrade nailing have either great enthusiasm or strong criticism for the procedure. Criticism of the procedure is because of the trauma that can occur to the rotator cuff and possible impingement syndrome, which can occur after antegrade nail insertion. The technique of retrograde nail insertion with the unreamed humeral nail is described in detail. In a series of 190 retrograde nailings performed in a prospective multicenter study, the most frequent intraoperative problems were fissure or avulsion at the entry portal (n = 8; 4.2%) and secondary radial nerve palsy (n = 8; 4.2%). All radial nerve palsies recovered spontaneously. Sixty-eight patients were followed up until the fractures healed. There were five (7.4%) bone healing problems. Four of five could be solved with use of the unreamed humeral nail in a second operative procedure, whereas the fifth bone healing problem required plate osteosynthesis. Function of the shoulder and elbow joint was excellent in 89.7% and 88.3% of the patients, respectively. Retrograde humeral nailing is a safe and reliable procedure if done properly. It is a valuable stabilization technique for acute and pathologic fractures and for pseudarthrosis. Bone healing problems after unreamed humeral nailing must be analyzed individually, but they can be treated with the same implant in combination with cancellous bone grafts, reaming, additional hardware, or intrafragmentary compression.

Adolescent↗
PubMed1997

Modulation of the swelling-activated amino acid channel of Leishmania major promastigotes by protein kinases.

Leishmania promastigotes respond to hypotonic challenges by a mechanism of regulatory volume decrease (RVD), whereby anionic amino acid channels (HAAC) are hypotonically-activated and intracellular amino acids are released from the cells. Irrespective of the experimental conditions, restoration of isotonicity triggered an immediate blockage of the amino acid release. Both the speed and amplitude of the response depended on the hypotonic stimulus and on the operation of intracellular signaling mechanisms. The initial (5 s) hypotonic-induced release of amino acids (ri) and the steady state levels of amino acids attained (5 min) or amplitude (A), were markedly affected by modulators of protein kinase C: phorbol 12-myristate 13-acetate, 1-oleoyl-2-acetylglycerol and phorbol 12,13-diacetate whereas staurosporine and the related analog, bis-indolylmaleimide I (GF-109203.X) inhibited the RVD response. Agonists of cAMP-dependent protein kinase A such as forskolin or (8-(4-chlorophenylthio))-adenosine-3',5'cyclic-monophosphate enhanced the speed of the response but had little effect on its amplitude. Neither 4alpha-phorbol 12,13-didecanoate,1,9-dideoxyforskolin nor genistein, tamoxifen or thapsigargin had any apparent effect on either parameter tested. The most striking stimulation of hypotonic-induced amino acid release was exerted by arachidonic acid or by its non-metabolizable analog, 5,8,11,14-eicosatetraynoic acid (ETYA). These agents caused a major increase in the initial rate of amino acid release as well as a higher amplitude of the response, both of which were markedly inhibited by an anion channel blocker. The present studies indicate not only that hypotonicity is an obligatory and dominant component in HAAC activation, but implicate specific second messengers in the modulation of the RVD response. The modes of activation or attenuation of HAAC activity apparently differ for PKC and PKA modulators as well as for arachidonic acid. The involvement of Ca2+ in HAAC was studied in hypotonic challenged cells which were treated with intracellular Ca2+-chelators or Ca2+-free medium. These cells showed a lag in AA release and a modest inhibition of the amplitude. The inhibition of HAAC was markedly increased when cells were treated with the ionophore A23187 in Ca2+-free media. The HAAC activity was accompanied by a significant increase in internal Ca2+ when performed in Ca2+-containing medium (from 88+/-9 to 179+/-22 nM) but by no significant change when measured in Ca2+-free medium. These studies indicate that although Ca2+ might be involved in the early activation phase of HAAC, it is either not absolutely required or its action might be associated with localized events.

Amino Acids↗
PubMed1997

Analysis of the FHIT gene and FRA3B region in sporadic breast cancer, preneoplastic lesions, and familial breast cancer probands.

The FHIT gene, which spans the FRA3B fragile site at chromosome 3p14.2, is a candidate tumor suppressor gene in breast and other cancers. We investigated FHIT and FRA3B for loss of heterozygosity (LOH); homozygous deletions; abnormal transcripts; and acquired/germ-line point mutations in breast cancer cell lines (n = 32), breast epithelial and stromal cell cultures (n = 18), microdissected invasive (n = 16) and ductal in situ carcinomas (n = 6), and their accompanying normal and abnormal epithelial foci (n = 14). LOH at 3p14.2, especially at FHIT intragenic marker D3S1300, was found in 6 of 16 microdissected invasive tumors and 3 of 6 ductal in situ carcinomas. In accompanying preneoplastic foci, LOH occurred in two of eight intraductal hyperplasias but not in histologically normal ductal epithelium (n = 6). Three of 32 (9%) breast cancer cell lines demonstrated homozygous deletions of FHIT exon 4 (two cases) and exon 5 (one case), which correlated with exon 4-deleted transcripts and loss of the cDNA transcript containing the coding exons 5-9, respectively. Normal mammary cultures and 31 of 32 tumor cell lines (97%) expressed wild-type coding transcripts as well as a minor exon 8-deleted message. Single-strand conformation polymorphism analysis of the coding exons in the 32 tumor and 18 normal breast cell lines and their sequencing revealed four silent polymorphisms and a germ-line histidine triad point mutation (651 G-->T) in a tumor arising in a 70-year-old woman. This mutation was also present in one of her two thus far unaffected daughters. Analysis of additional DNAs from 280 probands of high-risk breast cancer families for other FHIT exon 8 mutations detected an intronic point mutation 13 bases upstream of exon 8. Thus, we have demonstrated relatively early abnormalities of the FHIT/FRA3B region in breast cancer and discovered two rare FHIT germ-line mutations. The expression of a transcript containing the coding exons in nearly all cell lines, including those with germ-line mutations, suggests the possibility that another gene in the FRA3B region may be involved in the pathogenesis of breast cancer.

Acid Anhydride Hydrolases↗