Biomedical subjects
K Gross
Publications and source records attributed to K Gross.
Best diagnostic method for floating kidney is sequential bone scintigraphy with the patient in the supine and upright positions.
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Cadmium-induced changes in antioxidative systems, hydrogen peroxide content, and differentiation in Scots pine roots.
To investigate whether Cd induces common plant defense pathways or unspecific necrosis, the temporal sequence of physiological reactions, including hydrogen peroxide (H(2)O(2)) production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism (peroxidases, phenolics, and lignification), and developmental changes, was characterized in roots of hydroponically grown Scots pine (Pinus sylvestris) seedlings. Cd (50 microM, 6 h) initially increased superoxide dismutase, inhibited the systems involved in H(2)O(2) removal (glutathione/glutathione reductase, catalase [CAT], and ascorbate peroxidase [APX]), and caused H(2)O(2) accumulation. Elongation of the roots was completely inhibited within 12 h. After 24 h, glutathione reductase activities recovered to control levels; APX and CAT were stimulated by factors of 5.5 and 1.5. Cell death was increased. After 48 h, nonspecific peroxidases and lignification were increased, and APX and CAT activities were decreased. Histochemical analysis showed that soluble phenolics accumulated in the cytosol of Cd-treated roots but lignification was confined to newly formed protoxylem elements, which were found in the region of the root tip that normally constitutes the elongation zone. Roots exposed to 5 microM Cd showed less pronounced responses and only a small decrease in the elongation rate. These results suggest that in cells challenged by Cd at concentrations exceeding the detoxification capacity, H(2)O(2) accumulated because of an imbalance of redox systems. This, in turn, may have triggered the developmental program leading to xylogenesis. In conclusion, Cd did not cause necrotic injury in root tips but appeared to expedite differentiation, thus leading to accelerated aging.
Role of interferon gamma in the pathogenesis of primary respiratory syncytial virus infection in BALB/c mice.
Immunologic mechanisms are thought to contribute to the pathogenesis of respiratory syncytial virus (RSV) bronchiolitis in humans. RSV-infected BALB/c mice exhibit tachypnea and signs of outflow obstruction, similar to symptoms in humans. Interferon gamma (IFNgamma) has been found to be the predominant cytokine produced in humans and mice with RSV infection. We therefore undertook this study to evaluate the role of IFNgamma in the development of respiratory illness in RSV-infected mice. BALB/c mice were infected with RSV, and lung function was assessed by plethysmography. Bronchoalveolar lavage (BAL) fluids were analyzed for the concentration of interferon gamma (IFNgamma) and the presence of inflammatory cells, and lung tissue sections were examined for histopathologic changes. The role of IFNgamma was further addressed in studies of IFNgamma knock-out mice (IFNgamma(-/-)) and of mice depleted of IFNgamma by in vivo administration of a neutralizing antibody. After infection, mice developed respiratory symptoms that were strongly associated with the number of inflammatory cells in BAL, as well as with the concentrations of IFN-gamma. Both IFN-gamma(-/-) mice and mice treated with anti-IFNgamma developed more extensive inflammation of the airways than control mice. However mice lacking IFNgamma exhibited less severe signs of airway obstruction. Together these data suggest a protective role of IFNgamma in RSV infection in terms of limiting viral replication and inflammatory responses but also a pathogenic role in causing airway obstruction.
Assessing depression with the MMPI and MMPI-2.
The usefulness of the MMPI (Hathaway & McKinley, 1951 ) and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) for diagnosing and assessing symptomatic depression has been the subject of considerable debate for a number of years. In this article, we review the relative contributions of the MMPI and MMPI-2 clinical and content scales in predicting depression. Positive predictive power, negative predictive power, and overall classification rate were computed for Scale 2 (D) of the MMPI and MMPI-2 and the Depression content scale (DEP) of the MMPI-2. Scale 2 (D) of both the MMPI and MMPI-2 appears to be moderately accurate in predicting depression. Although some studies suggest that the content scale DEP provides incremental validity over Scale 2 (D) of the MMPI-2, the results of this review indicate that the content scale DEP of the MMPI-2 does not exceed the diagnostic efficiency of Scale 2 in predicting depression.
Acute versus chronic aortic occlusion .
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Stability and variability in competitive communities.
Long-term variability in the abundance of populations depends on the sensitivity of species to environmental fluctuations and the amplification of environmental fluctuations by interactions among species. Although competitive interactions and species number may have diverse effects on variability measured at the individual species level, a combination of theoretical analyses shows that these factors have no effect on variability measured at the community level. Therefore, biodiversity may increase community stability by promoting diversity among species in their responses to environmental fluctuations, but increasing the number and strength of competitive interactions has little effect.
Axillary lymph node uptake of Tc-99m MIBI resulting from extravasation should not be misinterpreted as metastasis.
Ipsilateral axillary lymph node visualization due to extravasation of Tc-99m MDP intravenous injection has been well documented. A patient with suspected angina underwent Tc-99m MIBI myocardial SPECT who had extravasation of Tc-99m MIBI in the antecubital region resulting in ipsilateral axillary lymph node uptake. This finding should not be misinterpreted as lymphatic nodal metastasis in a patient with breast cancer or lung cancer.
Internal carotid artery occlusion.
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Consecutive brain SPECT surface three-dimensional displays show progression of cerebral cortical abnormalities in Alzheimer's disease
PURPOSE: To monitor progression of cerebral blood flow deterioration, this study used consecutive surface SPECT to evaluate the feasibility of brain surface displays (BSD) to follow Alzheimer's disease (AD) to determine whether overtime is a consistent feature of the disease. METHODS: Eighteen men (mean age, 75.7 years) with probable Alzheimer's disease (AD), with moderate to profound dementia indicated by the Mini-Mental State Examination (MMSE; median score, 10; range, 0 to 19), underwent brain Tc-99m ethyl cysteinate dimer SPECT. Brain SPECTs were obtained using a three-head gamma camera. Brain surface displays (BSD) were reconstructed from transaxial data using a threshold of 55% of the maximum pixel count. A second series of SPECTs were obtained after 5 to 23 months (except for one, which was done after 60 months). Each BSD was graded semiquantitatively, by visual interpretation, from zero to 8 (normal = 0, mild = 2, moderate = 4, severe = 6, and profound = 8) depending on the extent of the perfusion defects in the frontal, temporal, or parietal (or all of these) pattern of AD. MMSE scores were used to calculate "time index" values for estimating severity at the time of the SPECTs. RESULTS: The initial BSD scores correlated significantly with dementia severity (r = 0.71, P < 0.001). All 18 patients had decreased blood flow on consecutive SPECTs. Scores for BSD progressed at a rate of 2.5 +/- 1.7 points per year and correlated significantly with the time interval between the scans (r = 0.71; P < 0.001). CONCLUSIONS: The BSDs of SPECT scan data have considerable objective discriminatory power for assessing the severity and progression of AD-related hypoperfusion, particularly in the moderate to profound dementia ranges, and is potentially more reliable than the MMSE. Consecutive BSDs simplify SPECT image interpretation for measuring loss of brain function over time and could be useful for assessing the efficacy of therapeutic interventions for AD patients such as vitamin E and cholinesterase inhibitors.
Under control of the Ren-1c promoter, locally produced transforming growth factor-beta1 induces accumulation of glomerular extracellular matrix in transgenic mice.
Our purpose was to elucidate the hypothesis that paracrine-produced transforming growth factor (TGF)-beta1 regulates the accumulation of extracellular matrix (ECM) in renal glomeruli, a hallmark of diabetic nephropathy. To produce TGF-beta1 from the juxtaglomerular apparatus in mouse kidneys, we cloned a mouse Ren-1c promoter fragment (-4.100 to +6 base pairs) upstream of porcine TGF-beta1 (pTGF-beta1) cDNA, mutated to ensure secretion of biologically active TGF-beta beta1. The resulting transgenic mice had significantly more TGF-beta1 in their kidneys than was in those of nontransgenic controls, as confirmed by immunohistochemistry, and the production of TGF-beta1 was enhanced in vivo by captopril-induced stimulation of the Ren-1c promoter. Overproduction of pTGF-beta1 close to the glomerulus resulted in a local accumulation of ECM, composed partly of collagen type IV and laminin, and thickening of the basement membrane, characteristic features of diabetic nephropathy. Interstitial accumulation of ECM and signs of tubular atrophy were present only in older mice (>5 months of age). Results from in situ hybridization and immunohistochemistry suggest that pTGF-beta1 stimulated the production of endogenous TGF-beta1 along collecting ducts and connecting tubules. The increased amount of biologically active TGF-beta1, transgenic as well as endogenous, was corroborated by heightened proteoglycan synthesis from incubated kidney slices. This transgenic model demonstrates that sustained local expression of TGF-beta1 leads to glomerulopathy. We conclude that autocrine- or paracrine-produced TGF-beta1 may play a role in the development of glomerular diseases, such as diabetic nephropathy.
Reliability of taurine concentrations measured in single urine samples obtained from dogs eight hours after eating.
OBJECTIVE: To evaluate the reliability of taurine concentrations measured in a single urine sample obtained from dogs 8 hours after eating, compared with taurine concentrations measured in 24-hour urine samples. ANIMALS: 18 healthy Beagles. PROCEDURE: After emptying the urinary bladder by transurethral catheterization, dogs were fed a canned maintenance diet. Approximately 8 hours later, urine, plasma, and serum samples were obtained for determination of fractional urinary excretion of taurine and urine taurine-to-creatinine concentration ratios (Utaur:Ucr). Results were compared with 24-hour urinary taurine excretion rate. RESULTS: Unbound and total fractional urinary taurine excretion correlated well with unbound and total 24-hour urinary taurine excretion. However, bound fractional urinary taurine excretion correlated poorly with bound 24-hour urinary taurine excretion. Unbound and total Utaur:Ucr correlated well with unbound and total 24-hour urinary taurine excretion. However, bound Utaur:Ucr correlated poorly with bound 24-hour urinary taurine excretion. CONCLUSION AND CLINICAL RELEVANCE: Fractional urinary excretion of unbound and total taurine, and unbound and total Utaur:Ucr are reliable indicators of 24-hour urinary unbound and total taurine excretion in healthy dogs. However, determination of 24-hour urinary taurine excretion is recommended for evaluating urinary bound taurine concentrations of dogs.
Myositis ossificans demonstrated by positive gallium-67 and technetium-99m-HMDP bone imaging but negative technetium-99m-MIBI imaging.
Gallium-67-citrate and 99mTc-diphosphate bone imaging agents are localized in myositis ossificans, a tumor-like benign soft-tissue mass that makes it impossible to differentiate between malignant tumor and the infection/inflammatory process. We present such a myositis ossificans patient whose bone and 67Ga-citrate imagings showed increased uptake in the left thigh and two foci of the right gluteal region leading to inconclusive results. Technetium-99m-MIBI imaging showed the absence of substantial uptake in these regions. ACT scan confirmed myositis ossificans. The lack of 99mTc-MIBI uptake in myositis ossificans means that 99mTc-MIBI imaging may be useful in the differential diagnosis.
Aneuploidogenic and clastogenic potential of the mycotoxins citrinin and patulin.
The aneuploidogenic and clastogenic potentials of the mycotoxins citrinin (CIT) and patulin (PAT) were studied by determining inhibition of microtubule assembly under cell-free conditions and by measuring induction of mitotic arrest and micronuclei in cultured Chinese hamster V79 cells. Both CIT and PAT inhibited cell-free microtubule polymerization in a concentration-dependent manner. PAT, but not CIT, bound covalently to reactive thiol groups of microtubule proteins. At concentrations without gross cytotoxicity, mitotic arrest and CREST-positive micronuclei, i.e. micronuclei containing whole chromosomes/chromatids, were induced by CIT and PAT in V79 cells. The time course of micronucleus induction and positive CREST staining indicate the aneuploidogenic potential of CIT and PAT. CREST-negative micronuclei, i.e. micronuclei containing acentric chromosomal fragments, were induced by PAT but not by CIT, implying a clastogenic potential of PAT. The aneuploidogenic and clastogenic potential of PAT and the aneuploidogenic potential of CIT may well contribute to the putative carcinogenicity of these mycotoxins in long-term animal studies.
Characterization of serum lipoprotein profiles of healthy, adult cats and idiopathic feline hepatic lipidosis patients.
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