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Biomedical subjects

L Ma

Publications and source records attributed to L Ma.

623 records · Page 35Linked to original sources

Red blood cell membrane abnormalities during storage: correlation with in vivo survival.

Experiments with citrate-phosphate-dextrose supplemented with adenine, 0.5 mM final concentration (CPD-A2), provided an opportunity for study of red blood cells (RBC) membrane storage lesions which could limit extension of storage. Impairment in drug-induced endocytosis in intact RBC occurred with storage, but the changes produced did not quantitatively predict or reflect the 24-hour in vivo 51Cr-labelled RBC survival. Abnormalities in RBC membrane protein did appear after storage, but these alterations neither paralleled nor predicted the in vivo 24-hour 51Cr-labelled RBC survival. The RBC membrance protein changes were not reminiscent of those produced by either acute adenosine triphosphate depletion, oxidative attack, or calcium accumulation. Therefore, while storage produces significant alterations in RBC membrane protein and function, the changes detected were not those that determined in vivo RBC survival.

Adenine↗

Actin inclusions in stromal cells of fibroepithelial tumor of breast: immunohistochemical and ultrastructural studies.

An uncommon occurrence of actin inclusions in the stromal cells of a benign fibroepithelial tumor of breast is reported. Histologically, many of the stromal cells contained round and eosinophilic intracytoplasmic inclusions identical to those seen in inclusion body fibromatosis. Ultrastructurally, these inclusions represented dense spherical clumps of microfilaments derived from rough endoplasmic reticulum. The literature was reviewed and follow-up data showed that the clinical course of these morphologically distinctive benign fibroepithelial tumors was relatively indolent if completely excised, in contrast to inclusion body fibromatosis, which commonly recurs. The pathogenesis may be related to abnormal production of truncated actin filaments or alteration in microenvironment.

Actins↗

Cigarette smoke increases apoptosis in the gastric mucosa: role of epidermal growth factor.

BACKGROUND/AIMS: Apoptosis is a common mechanism for the regulation of cell loss. It is associated with both tissue atrophy and metaplasia. Cigarette smoking has tremendous adverse effects on the stomach and also increases the risk of gastric cancer. This action may be through the change in apoptosis in the stomach. The aim of this study was to examine the effect of cigarette smoking on apoptosis in the gastric mucosa and the possible role of epidermal growth factor (EGF) in this action. METHODS: Gastric blood flow was assessed by the laser Doppler technique. Serum and gastric mucosal EGF levels were measured by RIA. Gastric mucosal apoptosis was determined using TdT-mediated dUTP-biotin nick end labeling (TUNEL). RESULTS: Cigarette smoke exposure decreased serum EGF which was accompanied by a reduction in gastric blood flow. Meanwhile, gastric mucosal cell apoptosis was increased. Administration of EGF (20 microg/kg i.v.) before each cigarette smoke exposure reversed these actions. Removal of salivary glands induced similar effects on the gastric blood flow, apoptosis, and serum EGF level as with cigarette smoke exposure. CONCLUSION: A reduction in serum EGF was involved in the decrease in gastric blood flow and increase in gastric mucosal apoptosis caused by cigarette smoking.

Analysis of Variance↗

'Spontaneous' regression of advanced leiomyosarcoma of the urinary bladder.

A case of advanced leiomyosarcoma of the urinary bladder is reported in a 25-year old man who, in a short time, experienced a complete 'spontaneous' regression of his fatal illness. He first presented with severe haemoperitoneum resulting from an unresectable bleeding tumour of the urinary bladder. Debulking surgery was performed, followed by salvage chemotherapy. Histological and ultrastructural examinations of the tumour confirmed a poorly differentiated leiomyosarcoma. The residual disease failed to respond to salvage chemotherapy, but regressed 'spontaneously' 5 months after cessation of therapy. The patient is alive without evidence of disease 51 months after the diagnosis. This remarkable phenomenon and relatively long survival in a poor-risk leiomyosarcoma of the urinary bladder has never been reported previously.

Adult↗

A pilot study of intracavitary hyperthermia combined with radiation in the treatment of oesophageal carcinoma.

Twenty-five patients with primary squamous cell carcinoma of the oesophagus were treated with intracavitary hyperthermia combined with external beam radiation and intraluminal radiation at Nanjing Jinling Hospital, China. External beam radiation was given with a 6-MV X-ray; 1.8-2.0 Gy per fraction and five fractions per week; this brought the total dose to 60 Gy. Two weeks later, hyperthermia was applied with 915 MHz microwave intracavitary applicators, which were designed at the City of Hope. Temperature measurements were obtained while moving fibreoptic temperature sensors at 1.0 cm intervals in each of the six peripheral channels of the applicator. Hyperthermia was applied for 1 h before and after the intraluminal radiation. Intraluminal radiation was provided by low dose-rate iridium-192 ribbons in the same intracavitary applicator, giving 30 Gy at 0.75 cm from the applicator surface. The 3-month post-treatment responses showing complete response, partial response, no change and progressive disease were 60% (15/25), 24% (6/25), 8% (2/25) and 8% (2/25) respectively. The median follow-up time was 17 months (range 4-29 months). The 1- and 2-year overall survival rates were 72% (18/25) and 32% (8/25) respectively, and disease-free survival rates were 47 and 30% respectively. The median overall survival and disease-free survival periods were 17 and 10 months respectively. Fourteen patients had local recurrence (either at the primary site or in the lymph node) or had local progression, and five developed metastases. The median duration of the onset of local recurrence or of local progression was 9.5 months (range 0-20 months); the median of distant metastases was 8 months (range 2-16 months). Seventeen patients died. Of these, 15 died of cancer: six with local recurrence alone, four with local progression primary cancer alone, three with distant metastases alone, and two with both local and distant failure. Two patients with complete response of the primary disease died of other diseases. The toxicity was mild. According to the mucous reaction scoring criteria of the Radiation Therapy Oncology Group, the acute toxicity grades I, II, III and IV were 0% (0/25), 20% (5/25), 48% (12/25) and 32% (8/25) respectively. The major late complication was a mild oesophagus fibrosis and difficult swallowing. No serious side effects (grade IV), fistulas or perforations were seen. These results indicate that this method is safe and feasible for treating oesophageal carcinoma.

Combined Modality Therapy↗

Neuronal NT-3 is not required for synaptic transmission or long-term potentiation in area CA1 of the adult rat hippocampus.

Neurotrophic factors, including BDNF and NT-3, have been implicated in the regulation of synaptic transmission and plasticity. Previous attempts to analyze synaptic transmission and plasticity in mice lacking the NT-3 gene have been hampered by the early death of the NT-3 homozygous knockout animals. We have bypassed this problem by examining synaptic transmission in mice in which the NT-3 gene is deleted in neurons later in development, by crossing animals expressing the CRE recombinase driven by the synapsin I promoter to animals in which the NT-3 gene is floxed. We conducted blind field potential recordings at the Schaffer collateral-CA1 synapse in hippocampal slices from homozygous knockout and wild-type mice. We examined the following indices of synaptic transmission: (1) input-output relationship; (2) paired-pulse facilitation; (3) post-tetanic potentiation; and (4) long-term potentiation: induced by two different protocols: (a) two trains of 100-Hz stimulation and (b) theta burst stimulation. We found no difference between the knockout and wild-type mice in any of the above measurements. These results suggest that neuronal NT-3 does not play an essential role in normal synaptic transmission and some forms of plasticity in the mouse hippocampus.

Animals↗

[Central effects of ORL1 receptor ligands].

It has been discussed literature data on molecular structure of ORL1 receptor and its interaction with intracellular signal systems and neurotransmitters. Data on chemical structure of ORL1 receptor ligands and their central effects (nociception, locomotion, feeding, cognition) are presented.

Animals↗

[Peripheral effects of ligands of ORL1 receptors].

It has been discussed literature data on the role for ORL1 (NOR) receptors in the regulation of function of gastrointestinal, respiratory, cardiovascular, immune, endocrine systems. In addition, it has been discussed a possibility of penetration of blood brain barrier for ORL1 receptor ligands and species dependence of NOR-ligands' effects.

Animals↗

Simulating nitrate drainage losses from a Walnut Creek watershed field.

This study was designed to evaluate the improved version of the Root Zone Water Quality Model (RZWQM) using 6 yr (1992-1997) of field-measured data from a field within Walnut Creek watershed located in central Iowa. Measured data included subsurface drainage flows, NO3-N concentrations and loads in subsurface drainage water, and corn (Zea mays L.) and soybean [Glycine mar (L.) Merr.] yields. The dominant soil within this field was Webster (fine-loamy, mixed, superactive, mesic Typic Endoaquolls) and cropping system was corn-soybean rotation. The model was calibrated with 1992 data and was validated with 1993 to 1997 data. Simulations of subsurface drainage flow closely matched observed data showing model efficiency of 99% (EF = 0.99), and difference (D) of 1% between measured and predicted data. The model simulated NO3-N losses with subsurface drainage water reasonably well with EF = 0.8 and D = 13%. The simulated corn grain yields were in close agreement with measured data with D < 10%. Nitrogen-scenario simulations demonstrated that corn yield response function reached a plateau when N-application rate exceeded 90 kg ha(-1). Fraction of applied N lost with subsurface drainage water varied from 7 to 16% when N-application rate varied from 30 to 180 kg ha(-1) after accounting for the nitrate loss with no-fertilizer application. These results indicate that the RZWQM has the potential to simulate the impact of N application rates on corn yields and NO3-N losses with subsurface drainage flows for agricultural fields in central Iowa.

Computer Simulation↗

Acupuncture in narcotic withdrawal: a preliminary report on biochemical changes in the blood and urine of heroin addicts.

Eight female heroin-addicted subjects were treated over a 10-day period by acupuncture and electrical stimulation (AES). Their plasma ACTH, cortisol and c-AMP levels were reduced after initial AES treatment. The reduction of c-AMP was significant the most of the three. The suppression of these compounds may be associated with the temporary relief of withdrawl symptoms on and after each AES treatment in the first three days. On the third day, ACTH, cortisol and c-AMP levels did not show significant changes after AES. This was presumably due to the disappearance of withdrawal symptoms and possibly to the stabilizing effect of the treatment. Both the ACTH and c-AMP levels were generally lower at the end of the treatment period. Results of the present investigation suggest that plasma c-AMP may be the best parameter by which to gauge the response of heroin addicts to AES.

Acupuncture Therapy↗