[Research progress on Pb-induced neurotoxicity through glial cells].

Lead is one of the most important occupational hazards in China, and occupational exposure is the leading cause of lead poisoning. Lead can be absorbed by the body through air, food, drinking water and skin, and accumulate in multiple organs in the body, posing health risks to humans, especially to lead workers. Many previous studies have shown that lead can affect the function of glial cells such as microglia, astrocytes and oligodendrocytes, resulting in irreversible neurological damage. This article provides an overview of the neurotoxic mechanism induced by lead through glial cells, elucidates that lead can induce neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, and reviews the relationship between lead and glial cells, in order to provide reference for further research on the neurotoxic mechanism of lead on glial cells.

[Impact of hyperoxia on the phenotype of pulmonary artery smooth muscle cells].

Objective: To investigate the influence of varied oxygen (O2) concentration environments on the phenotypic transformation of pulmonary artery smooth muscle cells (PASMC) and the mechanism of pulmonary hypertension. Methods: Primary rat PASMC were isolated and cultured through the process of enzymatic digestion. Following identification, the stable passaged PASMC were subjected to a 6-hour incubation in sealed containers with normal O2 content (group C) and relative O2 content comprising 55% (group H55), 75% (group H75), and 95% (group H95). mRNA and protein expression of α-Actin (α-SMA), smooth muscle 22α (SM22α), osteopontin (OPN), and matrix metalloproteinase-2 (MMP-2) were measured using real-time quantitative PCR and western blot analysis. Results: The H55 group displayed no significant difference from the C group in terms of mRNA and relative protein expression levels for α-SMA, SM22α, OPN, and MMP-2 (all P>0.05). On the other hand, groups H75 and H95 exhibited a reduction in mRNA and relative protein expression of α-SMA and SM22α, along with an increase in mRNA and relative protein expression of OPN and MMP-2 when compared with both the C and H55 groups (all P<0.05). The H95 group showed a higher relative mRNA expression of MMP-2 as compared to the H75 group (P<0.05). Conclusions: Oxygen concentration environments of 75% or higher can serve as the foundation for the pathogenesis of pulmonary hypertension, essentially by inducing a phenotypic transformation in PASMC towards adopting a robust secretory function. This induction is contingent upon the concentration of oxygen present.

[Whole brain causal functional connectivity analysis of noise-induced deafness based on resting state-functional magnetic resonance imaging].

Objective: To investigate the changes of directional connections of auditory and non-auditory in patients with noise-induced deafness (NID) by degree centrality (DC) and Granger causality analysis (GCA), and to explore the mode of brain function remodeling after NID. Methods: In October 2023, a total of 58 patients diagnosed with NID by the Occupational Diseases Department of Yantaishan Hospital of Yantai from 2014 to 2022 were collected as case group (NID group), and 42 healthy volunteers matched by gender, age and education level were selected as the control group (HC group). Resting state-functional magnetic resonance imaging (Rs-fMRI) was perfomed and PC analysis was performed. The brain regions with statistically significant differences in DC values between groups and the bilateral Heschl regions were extracted as regions of interest (ROI) for voxel-based whole brain GCA and correlation analysis. Results: Compared with HC group, the SOG.L DC value of NID group was lower, the connectivity values of SFGdor.L to SOG.L was increased, the connectivity value of PCL.L to SOG.L was decreased, the connectivity values of ORBmid.L, PCG.R and CUN. L/R to HES.L were increased, the connectivity value of SFGdor.L to HES.L was decreased, the connectivity value of HES.L to PCUN.L was decreased, the connectivity values of ORBsup.L and PCG.R to HES.R were increased, the connectivity value of HES.R to CUN.L was decreased (P voxel level<0.01, P cluster level<0.05). The connectivity value of PCL.L to SOG.L was negatively correlated with the weighted value of the better whisper frequency (P<0.05) . Conclusion: The NID patients have abnormal directional connectivity activity in multiple brain regions, such as auditory vision, executive control, somatosensory movement, and default mode network. It is suggested that hearing loss may cause complex neural remodeling between auditory and non-auditory centers.

[Preoperative dynamic contrast-enhanced MRI can reduce the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma].

Objective: To investigate the value of preoperative dynamic contrast-enhanced MRI in reducing the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma. Methods: Seventy-two patients with early non-mass breast carcinoma received ultrasonographic and mammographic examination and subsequently underwent dynamic contrast-enhanced MRI examination before breast conserving surgery. The control group consisted of 74 patients who had early non-mass breast carcinoma. They only received ultrasonographic and mammographic examination and didn't undergo contrast-enhanced MRI examination. The comparison of the rate of tumor-positive resection margins between two groups was performed. The MRI findings that had the significant influence on the rate of tumor-positive resection margins were analyzed using Logistic regression model. Results: In 28 patients (28/72, 38.9%), dynamic contrast-enhanced MRI could correct or supplement the ultrasonographic and mammographic findings and resulted in the reasonable change of surgical program. The preoperative MRI examination group (n=30) had lower rate of tumor-positive resection margins than control group for invasive ductal carcinoma (23.3% vs 40.0%, P=0.02), but there was no significant difference (21.4% vs 26.9%, P=0.10) between two groups for ductal carcinoma in situ (n=28). The preoperative MRI examination group (n=14) had lower rate of tumor-positive resection margins than control group for the other pathologic types of breast carcinoma (14.3% vs 38.9%, P=0.02). The statistical analysis on the basis of Logistic regression model showed that some main MRI findings, including change surrounding the tumor, distance between tumor and nipple and tumor size, had the significant influence on the rate of tumor-positive resection margins. Conclusion: Preoperative dynamic contrast-enhanced MRI significantly increased the accuracy of resection margins evaluation, and greatly reduced the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma.

Urinary incontinence after radical retropubic prostatectomy is not related to patient body mass index.

To determine if a relationship exists between patient body habitus and urinary incontinence after radical retropubic prostatectomy (RRP) for clinically localized prostate cancer. A questionnaire developed by combining parts of lower urinary tract symptom questionnaires concerning voiding symptoms after RRP was mailed to 268 consecutive patients who underwent RRP over a 2-year period. The interval between surgery and questionnaire administration was greater than 24 months for each patient. No interval was greater than 54 months. The questionnaire attempted to overcome the subjectivity of patient documented urinary incontinence by probing different aspects of each patient's voiding symptoms. Body mass index (BMI), obtained from preoperative anesthesia records, was used as the measurement for body habitus. Pearson correlations were used to determine relationships between BMI and responses and the independent t-test was used to determine differences between grouped responses and BMI. One hundred and eighty-two of 268 (68%) questionnaires were returned. No relationship was detected between BMI and patient estimates of urinary control, QOL relating to urinary symptoms, severity of stress incontinence, or use of protection (pad use). As well, no statistically significant relationship was found between BMI and a patient's willingness to undergo RRP again, based on his voiding symptoms, if given the choice. In conclusion, although patient body habitus may be related to other clinical outcomes following RRP, there does not appear to be a relationship of BMI to post-RRP urinary incontinence.

Accelerated treatment of breast cancer.

PURPOSE: Radiation therapy (RT) restricted to the tumor bed, by means of an interstitial implant, and lasting 4 to 5 days after lumpectomy was prospectively evaluated in early-stage breast cancer patients treated with breast-conserving therapy (BCT). The goals of the study were to determine whether treatment time can be reduced and whether elective treatment of the entire breast is necessary. MATERIALS AND METHODS: Between January 1993 and January 2000, 174 cases of early-stage breast cancer were managed with lumpectomy followed by RT restricted to the tumor bed using an interstitial implant. Each brachytherapy patient was matched with one external-beam RT (ERT) patient derived from a reference group of 1,388 patients treated with standard BCT. Patients were matched for age, tumor size, histology, margins of excision, absence of an extensive intraductal component, nodal status, estrogen receptor status, and tamoxifen use. Median follow-up for both the ERT and brachytherapy groups was 36 months. RESULTS: No statistically significant differences were noted in the 5-year actuarial rates of ipsilateral breast treatment failure or locoregional failure between ERT and brachytherapy patients (1% v 0%, P =.31 and 2% v 1%, P =.63, respectively). In addition, there were no statistically significant differences noted in rates of distant metastasis (6% v 3%, P =.24), disease-free survival (87% v 91%, P =.55), overall survival (90% v 93%, P =.66), or cause-specific survival (97% v 99%, P =.28). CONCLUSION: Accelerated treatment of breast cancer using an interstitial implant to deliver radiation to the tumor bed alone over 4 to 5 days seems to produce 5-year results equivalent to those achieved with conventional ERT. Extended follow-up will be required to determine the long-term efficacy of this treatment approach.

Specific activation of Gs by synthetic peptides corresponding to an intracellular loop of the beta-adrenergic receptor.

Peptides corresponding to the amino acid sequence of the hamster beta 2-adrenergic receptor (beta 2AR) were synthesized and their ability to activate purified G-proteins determined. Two peptides, comprising the N- and C-terminal 15 amino acids of the putative third intracellular loop region of the beta 2AR were found to activate the G-protein Gs but not to activate a preparation of Gi/Go. Other peptides corresponding to the internal portions of this loop and the C-terminal tail region failed to activate either G-protein. The presence of phospholipid vesicles was required for this activation. The observation that peptides with sequences corresponding to the ends of the third intracellular loop of the beta AR can specifically activate Gs confirms the results of previous mutagenesis studies on the receptor and demonstrates that the secondary structure conferred by the amino acid sequences in these regions is sufficient for the activation of G-proteins.

Detection of tyrosinase mRNA in formalin-fixed, paraffin-embedded archival sections of melanoma, using the reverse transcriptase in situ polymerase chain reaction.

Most studies of the reverse transcriptase in situ polymerase chain reaction technique have reported results from assessments of cultured cells, frozen sections, and cytospin preparations. For application to routine diagnosis, it will be necessary to adapt the technique for use with formalin-fixed, paraffin-embedded tissues, the materials that are generally available. We have evaluated the feasibility of such an approach, using surgical pathology archival material from 25 UCLA patients: 15 tissues from primary and metastatic melanoma, 7 from nonmelanocytic tumors, including cancer of the lung, colon, kidney and skin and a thyroid adenoma, and 3 nontumorous tissues. Seven of 15 melanoma tissues gave a strong positive signal, 5 gave a weak signal, and 3 were negative. None of the 10 nonmelanoma tissues gave a positive signal. The specific reaction product was mainly located in the cytoplasm. None of the nonmelanocytic tumors or normal tissues demonstrated this pattern of cytoplasmic staining. Some nonspecific nuclear staining was observed in melanocytic and nonmelanocytic tumors and must not be overread as a true positive result. It is possible to detect tyrosinase mRNA in formalin-fixed, paraffin-embedded tissue sections of melanoma, but the technique remains too demanding for routine application.

Structure-function studies on the cyclic peptide MT-II, lactam derivative of alpha-melanotropin.

The alanine-substituted and the retro, enantio, and retro-enantio analogs of MT-II, a potent agonist at melanocortin (MC) receptors, were prepared by solid-phase synthesis and evaluated for their ability to bind and activate human MC3, MC4, and MC5 receptors. Replacement of His with Ala resulted in [Ala6]-MT-II with affinity and agonist potency at human MC3, MC4, and MC5 receptors similar to MT-II. Substitution of Arg with Ala gave compound 100-fold less potent than MT-II, but replacement of Phe or Trp with Ala led to inactive compounds (at the micromolar concentrations). The significant drop of potency of the retro, enantio, and retro-enantio analogs of MT-II, demonstrated a crucial role of side-chain topology, and to a lesser degree, of peptide backbone in interactions of MT-II with the melanocortin receptors. The nuclear magnetic resonance analysis of MT-II suggested involvement of Phe and Arg residues in H-bonds stabilizing the bent conformations of the peptide backbone.

Characterization of the binding of [125I-iodo-histidyl, methyl-Phe7] neurokinin B to the neurokinin-3 receptor.

We have characterized the binding of [125I-iodo-histidyl, methyl Phe7]neurokinin B (125I-NKB) to the human neurokinin-3 (NK3) receptor. 125I-NKB specifically binds to the NK3 receptor expressed in CHO cells with a Kd of 0.2 nM. The ligand displays little crossreactivity with the human NK1 and NK2 receptors. The binding of 125I-NKB to the human NK3 receptor and to rat cortex membranes is inhibited by neurokinin B with IC50 of 1.5 nM and 4 nM, respectively. In contrast, 350- to 500-fold higher concentrations of substance P and neurokinin A are required to inhibit binding to either receptor preparation. The data suggest that 125I-NKB is a high affinity, selective ligand for the human and rat NK3 receptor.

The effect of H2O2 on lens epithelial cell glutathione.

Investigation of lens epithelial cells indicates that under normal conditions, essentially all of the detectable cellular glutathione is in a reduced state. However, exposure to levels of H2O2 in the range found in the aqueous fluid of cataract patients causes rapid, very large changes in the glutathione redox ratios. Immediately following short-term exposure to 0.15-0.2 mM H2O2, reduced glutathione drops to 19% of its normal level and the remainder of the total glutathione is found in the oxidized form. Within the next few minutes, the redox ratio returns to normal. However, total glutathione levels remain approximately 20% below normal even one hour after exposure to H2O2. With exposure to a higher concentration of H2O2, a greater loss of glutathione is observed. The results suggest that the glutathione redox ratios change dramatically as a result of oxidative insult but quickly return to normal when the oxidative insult is removed. The formation of mixed glutathione-protein disulfide was also observed but only after long-term (1 hour) exposure to a high level (0.6 mM) of H2O2.

A new HPLC method to determine glutathione-protein mixed disulfide.

A sensitive method for measuring glutathione-protein mixed disulfides is described. The method is based on cleavage of the protein disulfides with performic acid followed by reaction with dinitrofluorobenzene and HPLC analysis with a Bondapak-amine column. Samples containing 0.1 nmoles or more of glutathione-protein mixed disulfide can be detected. The method has been used to demonstrate (a) the presence of low levels of glutathione mixed disulfide in gamma crystallin isolated from bovine lenses, (b) a dramatic increase in such mixed disulfides after exposure of denatured gamma crystallin to O2 in the presence of glutathione, and (c) the formation of glutathione-protein mixed disulfide in lens epithelial cells exposed to 0.6 mM H2O2 for one hour.

Selection and identification of antigenic determinant of Mycobacterium tuberculosis H37Ra strain.

A new procedure for the selection of the antigenic determinant of Mycobacterium tuberculosis H37Ra strain is described. The bacterium components destroyed by ultrasonic were isolated by 15% SDS-PAGE, transferred onto nitrocellulose membrane, immunostained with McAbs against H37Ra. One McAb-positive fragment was obtained using the Western blot analysis. The molecular weight of the antigenic determinant is 35,000 dalton. The antigenic determinant is of immunological reactivity with McAb and TB patients' sera in dot-immunoassay and demonstrated in delayed skin tests in guinea pigs. The amino acid composition of the antigenic determinant was analysed. These suggest that the Western blot analysis may be a useful tool for the analysis of the antigenic determinant.

[Purified protein derivative antigen purified by using a monoclonal antibody to Mycobacterium tuberculosis].

A component of Mycobacterium tuberculosis H37Rv PPD referred as C3Ag was purified with a column of affinity chromatography to which a monoclonal antibody (TB-15C3) was conjugated. C3Ag was found to have two bands in 56,000 and 66,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Western blot revealed that both fragments were recognized by TB-15C3. By ELISA C3Ag was shown to react with rabbit antisera against M. tuberculosis, M. Kansasii, M. screfulaceum, M. bovis BCG, but not to react substantially with antiserum against M. bovis. Among 82 sera from patients with pulmonary tuberculosis 60% showed positive reactions to C3Ag while for 100 normal control sera it was only 10%. C3Ag elicited a delayed cutaneous reaction in guinea pigs sensitized with heat killed M. tuberculosis, M. bovis and BCG. These results suggest that C3Ag might be an important fragment of H37Rv PPD.

Involvement of specific hydrophobic, but not hydrophilic, amino acids in the third intracellular loop of the beta-adrenergic receptor in the activation of Gs.

Mutagenesis and biochemical analysis have indicated that amino acid residues at the amino terminus of the third intracellular loops of guanine nucleotide-binding protein (G protein)-coupled receptors are important in mediating the coupling of the receptors to G proteins. Because the primary sequence of this region is not conserved among all receptors that couple to the same G protein, it has been suggested that some other physicochemical property of this domain may determine G protein activation. To determine the relative contributions of charge distribution and amino acid side chain interactions within this domain of the beta-adrenergic receptor (beta AR) to the activation of the G protein Gs, point mutations were introduced into this region of the beta AR. Replacement of all four of the basic amino acid residues within this region (amino acids 222-236) with serine residues had a negligible effect on the ability of the beta AR to activate Gs. In contrast, replacement of the hydrophobic amino acids within this same region with leucine residues resulted in a mutant receptor that was poorly coupled to Gs. These results suggest that specific hydrophobic interactions within this region of the receptor may play a more significant role than ionic or hydrophilic interactions in mediating G protein activation.

Localization of agonist and antagonist binding domains of the human neurokinin-1 receptor.

To identify the molecular determinants of ligand-receptor interactions, the extracellular domain of the human neurokinin-1 receptor was systematically substituted with the corresponding sequences from the other two neurokinin receptor subtypes. Three residues within the first extracellular segment and 2 residues of the second segment are required for the optimal binding of all three natural peptide agonists. The divergent nature of 4 of the 5 residues supports the hypothesis that the peptide binding site on the neurokinin-1 receptor is not highly conserved in the other two receptor subtypes. In contrast, substitution of part of the third extracellular segment and the fourth extracellular segment with the corresponding amino acids of the human neurokinin-3 receptor results in an increase in neurokinin B affinity without affecting substance P binding, suggesting that the two peptides do not interact with the same set of functional groups on the receptor. Among the four extracellular regions, only parts of the third and fourth segments affect the binding of the quinuclidine antagonist L-703,606, and these two regions may partially account for the neurokinin-1 receptor subtype specificity of this non-peptide antagonist. These studies demonstrate that both the extracellular and transmembrane domains of the neurokinin-1 receptor are involved in the binding of substance P and related peptides.

Pressure measurements in closed aneurysmal sac during abdominal aortic aneurysm resection.

PURPOSE: This study determined the relationship between closed aneurysmal sac pressure (ASP) and mean blood pressure (BP) during open abdominal aortic aneurysm (AAA) resection and evaluated the contribution of inferior mesenteric and lumbar artery blood flow to ASP after proximal and distal clamping. METHODS: We measured ASP after proximal and distal clamping by placing an 18-gauge needle connected to a BP transducer into the excluded aneurysmal sac in 25 consecutive patients from April 1999 to August 2000. Simultaneous measurement of the mean systemic BP was also recorded. The ratio of ASP to mean BP in relation to the number of actively bleeding lumbar arteries (N-LA), diameter of the AAA (D-Cm), and volume of the thrombus in the AAA (Vol-TA) were recorded. RESULTS: The mean ASP was 43.32 +/- 15.19 mm Hg, with an ASP to mean BP ratio of 0.47 +/- 0.15. The N-LA in the closed aneurysmal sac ranged from 0 to 6 (mean, 3.4 +/- 1.78). The D-Cm as determined by means of computed tomography (CT) scan of the aorta ranged from 5 to 8 cm in its largest anteroposterior/transverse diameter. The average Vol-TA was 6.15 +/- 4.49 mL. Inferior mesenteric artery blood flow contributed to ASP in three patients (12%). There was no correlation between ASP to mean BP ratios and the N-LA (P =.127), D-Cm (P =.882), or Vol-TA (P =.252). CONCLUSION: Closed ASP and ASP ratios are highly variable and do not correlate with N-LA, D-Cm, or the Vol-TA.

The extracellular domain of the neurokinin-1 receptor is required for high-affinity binding of peptides.

The neurokinin-1 receptor binds neurokinin peptides with the potency order of substance P > substance K > neurokinin B. Elucidating the molecular basis of differential peptide selectivity will require the localization of the binding domain on the receptor. In the present report, mutagenesis and heterologous expression experiments reveal that a segment of the extracellular N-terminal sequence of the neurokinin-1 receptor is required for the high-affinity binding of substance P and related peptide agonists. Substitution of amino acid residues in the N-terminal region of the receptor affects the binding affinity of both intact peptides and a C-terminal substance P "analog", but not of a nonpeptide antagonist. Glycosylation of the receptor does not change the peptide binding affinity. In addition, substitution of the valine-97 residue in the rat neurokinin-1 receptor by a glutamate residue increases the binding affinity of neurokinin B but not substance P or substance K, suggesting that the second extracellular segment is involved in peptide selectivity. These results indicate that the extracellular domains of neurokinin-1 receptor play a critical role in peptide binding.