"Molecular margins": a better measure?
Explore the source record for details and available documents.
Frozen Sections↗
Biomedical subjects
D Y Zhang
Publications and source records attributed to D Y Zhang.
Clinical and molecular pathology of aggressive Schneiderian papilloma involving the temporal bone.
BACKGROUND: Inverting papilloma is a benign but locally aggressive sinonasal tumor that rarely involves the middle ear or temporal bone. METHODS: A report of a case and the molecular pathology of the tumor is presented. RESULTS: A 35-year-old woman with a history of recurrent inverting papilloma of the left paranasal sinuses was found to have evidence of extension through the eustachian tube and extensive involvement of the temporal bone. Surgical management resulted in the patient being disease-free at 14 months. Molecular pathology studies of the resected tumor suggest an association with human papillomavirus. CONCLUSIONS: Direct extension of the sinonasal tumor through the eustachian tube may represent the pathologic mechanism involved in the development of inverting papilloma involving the middle ear and temporal bone.
Adult↗
Gestational changes in fetal renal and hepatic angiotensinogen mRNA and protein.
The aim of the study was to determine the amount of angiotensinogen expression and its protein product in fetal sheep liver and kidney in the last third of gestation. Angiotensinogen mRNA was measured by RNase protection assay and its protein levels were measured by radioimmunoassay. Levels were measured at 80, 95, 111, 125 and 139 days. Angiotensinogen mRNA was present in all fetal liver and kidney samples tested. The ratio of hepatic angiotensinogen mRNA/18 S rRNA increased by 100% (P < 0.001) and angiotensinogen levels increased by 33% (P < 0.001) in fetal sheep from 80 to 139 d. Over the same period the ratio of renal angiotensinogen mRNA/18 S rRNA increased by 170% (P < 0.001) and renal angiotensinogen protein increased by 41% (P < 0.001). The levels of angiotensinogen mRNA and its protein in the adult kidney were less than in kidneys of 139 d old fetuses (P < 0.01). There was a direct relationship between levels of angiotensinogen mRNA and its protein in the liver (r = 0.53, P < 0.01, n = 25) and in the kidney (r = 0.75, P < 0.0001, n = 24). These findings demonstrate that there is a significant increase in both hepatic and renal angiotensinogen gene expression in the last third of gestation in the fetal sheep and that this increase is associated with an increase of angiotensinogen levels in both tissues. This increase in angiotensinogen in late gestation could influence the activity of both the intrarenal and circulating renin angiotensin systems.
Angiotensinogen↗
Linkage of the MHC to familial multiple sclerosis suggests genetic heterogeneity. The Multiple Sclerosis Genetics Group.
Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system. While its etiology is not well understood, genetic factors are clearly involved. Until recently, most genetic studies in MS have been association studies using the case-control design testing specific candidate genes and studying only sporadic cases. The only consistently replicated finding has been an association with the HLA-DR2 allele within the major histocompatibility complex (MHC) on chromosome 6. Using the genetic linkage design, however, evidence for and against linkage of the MHC to MS has been found, fostering suggestions that sporadic and familial MS have different etiologies. Most recently, two of four genomic screens demonstrated linkage to the MHC, although specific allelic associations were not tested. Here, a dataset of 98 multiplex families was studied to test for an association to the HLA-DR2 allele in familial MS and to determine if genetic linkage to the MHC was due solely to such an association. Three highly polymorphic markers (HLA-DR, D6S273 and TNFbeta) in the MHC demonstrated strong genetic linkage (parametric lod scores of 4.60, 2.20 and 1.24, respectively) and a specific association with the HLA-DR2 allele was confirmed (TDT; P < 0.001). Stratifying the results by HLA-DR2 status showed that the linkage results were limited to families segregating HLA-DR2 alleles. These results demonstrate that genetic linkage to the MHC can be explained by the HLA-DR2 allelic association. They also indicate that sporadic and familial MS share a common genetic susceptibility. In addition, preliminary calculations suggest that the MHC explains between 17 and 62% of the genetic etiology of MS. This heterogeneity is also supported by the minority of families showing no linkage or association with loci within the MHC.
Alleles↗
Further study of hepatitis C virus RNA detection in formalin-fixed, paraffin-embedded liver tissues by ligation-dependent polymerase chain reaction.
Ligation-dependent polymerase chain reaction (LD-PCR) is a novel, simple and sensitive PCR assay that could be useful for the molecular diagnosis of various viral infections. This assay uses two capture probes for RNA isolation and two hemiprobes for the subsequent PCR. To investigate its usefulness in the field of pathological diagnosis, further study of this new PCR technology to detect hepatitis C virus (HCV) RNA was carried out in formalin-fixed, paraffin-embedded (FFPE) liver tissues and the results compared with those obtained by the reverse transcription (RT)-PCR method. We analyzed routinely processed FFPE liver specimens of surgical origin from 13 anti-HCV-seropositive Japanese patients with hepatocellular carcinoma (HCC). As a result, HCV-RNA was detected in FFPE liver specimens in 12 of the tested patients (92.3%) by the LD-PCR method without the use of reverse transcription. In contrast, HCV-RNA was detectable in eight out of 13 cases (61.5%) by the RT-PCR method. These results indicated that LD-PCR was useful for HCV-RNA detection in routinely processed FFPE liver specimens.
Adult↗
Changes in renal renin gene expression in fetal sheep.
1. Renin gene expression was investigated in kidneys from 13 foetal and four adult sheep. 2. The levels of renal renin mRNA in foetuses were greater than those in adult sheep (P < 0.001). 3. There was no significant difference in renin mRNA levels between foetuses aged 91 and 134 days (term 150 days). 4. The levels of renin gene expression were higher (178 +/- 5 units; P < 0.001) in foetuses at 142 days than levels in 91 (144 +/- 4 units) and 134 days old foetuses (146 +/- 6 units). 5. It is concluded that the high level of renin gene expression in the foetal kidney is responsible for the high levels of renin in the foetal circulation.
Animals↗
Novel, ligation-dependent PCR assay for detection of hepatitis C in serum.
A simple, sensitive, and specific ligation-dependent PCR (LD-PCR) method for the detection of hepatitis C virus (HCV) RNA in serum is described. The assay uses two DNA capture probes for RNA isolation and two DNA hemiprobes for subsequent PCR. Each capture probe has a 3' sequence complementary to the conserved 5' untranslated region of HCV RNA and a biotin moiety at the 5' end capable of interacting with streptavidin-coated paramagnetic beads. Each hemiprobe contains a sequence complementary to the 5' untranslated region in juxtaposition to one another and a common sequence for PCR primer binding. In guanidinium thiocyanate solutions, the capture probes and the hemiprobes form a hybrid with their target, and the hybrid can be isolated from serum by the binding of the capture probes to the paramagnetic beads in the presence of a magnetic field. The hemiprobes can then be linked to each other by incubation with T4 DNA ligase to form a full probe that serves as a template for a PCR. When serial 10-fold dilutions of synthetic HCV RNA (10(7) to 10 molecules) were tested, there was a good correlation between the amount of PCR product and the initial number of RNA molecules, with a sensitivity of 100 HCV RNA molecules per reaction. Twenty-four specimens that had been tested by either a branched DNA probe (bDNA) assay (13 specimens) or a reverse transcription PCR (RT-PCR) assay (11 specimens) were also analyzed by LD-PCR. The results showed a good correlation among LD-PCR, RT-PCR, and the bDNA assay. However, both LD-PCR and RT-PCR were more sensitive than the bDNA assay when the HCV titer was low.
Base Sequence↗
Detection of hepatitis C virus RNA using ligation-dependent polymerase chain reaction in formalin-fixed, paraffin-embedded liver tissues.
Reverse transcription polymerase chain reaction (RT-PCR) has been used to detect hepatitis C virus (HCV) sequences in liver tissue. However, RT-PCR has a variable detection sensitivity, especially on routinely processed formalin-fixed, paraffin-embedded (FFPE) specimens. RNA-RNA and RNA-protein cross-links formed during formalin fixation is the major limiting factor preventing reverse trans criptase from extending the primers. To overcome this problem, we applied the ligation-dependent PCR (LD-PCR) for the detection of HCV RNA in FFPE liver tissue. This method uses two capture probes for RNA isolation and two hemiprobes for the subsequent PCR. Despite cross-links, the capture probes and the hemiprobes are able to form hybrids with HCV RNAs released from the FFPE tissue. The hybrids are isolated through binding of the capture probes to paramagnetic beads. The hemiprobes are then ligated by a T4 DNA ligase to form a full probe that serves as a template for the Taq DNA polymerase. A total of 22 FFPE liver specimens, 21 with hepatocellular carcinoma (HCC) and 1 with biliary cirrhosis secondary to bile duct atresia were selected for this study, of which 13 patients were HCV seropositive and 9 seronegative. HCV RNA was detectable by ID-PCR from all 13 HCV-seropositive HCCs and from 5 of 8 HCV-seronegative HCCs but not from the HCV-seronegative liver with biliary atresia. By contrast, RT-PCR detected HCV sequences in only 5 of the HCV-sero-positive and in 1 of the HCV-seronegative HCCs. To resolve the discordance between the LD-PCR and RT-PCR results, RT-PCR was performed on frozen liver tissue of the discrepant specimens, which confirmed the LD-PCR positive results. In conclusion, LD-PCR is a more sensitive method than RT-PCR for the detection of HCV sequences in routinely processed liver tissues. A high rate of HCV infection (86%) is found in HCC specimens, indicating a previously underestimated role of HCV in HCC pathogenesis.
Base Sequence↗
Haemophilus parainfluenzae biliary tract infection: rationale for an ascending route of infection from the gastrointestinal tract.
Haemophilus parainfluenzae was isolated from a bile specimen of a 56-year-old patient with elevated liver enzymes and chronic cholecystitis. Several factors contributing to nonbacteremic H. parainfluenzae infection of the biliary tract include (i) the not infrequent occurrence of H. parainfluenzae in stool specimens, (ii) the presence of an outer membrane protein similar to those found in enteric bacteria which facilitates adherence to the colonic mucosa, and (iii) an adequate supply of V factor (nicotinamide adenine dinucleotide) supplied from bile and the local flora, which is necessary for H. parainfluenzae's growth. Because H. parainfluenzae rarely occurs in the biliary tract, direct cultivation of bile specimens on chocolate agar seems unwarranted. However, bile specimens showing a gram-negative coccobacillus on a Gram-stained smear that fails to grow on routine media should be subcultured on chocolate agar.
Biliary Tract Diseases↗
Regression of LNCaP human prostate tumor xenografts in athymic nude mice by 13-cis-retinoic acid and androgen ablation.
The present study was designed to investigate the effects of 13-cis-retinoic acid (13-cis-RA) (100 micrograms/mouse/day) and androgen ablation (castration) alone and in combination on growth of a human prostatic carcinoma line (LNCaP) transplanted to athymic nude mice as an experimental model. The results of these studies suggest that; (1) androgen ablation (castration) significantly decreased the size of LNCaP xenograft as compared to untreated animals; (2) when 13-cis-RA was administered to nude mice carrying established tumors (0.51 +/- 0.04 cm3), the tumor size was significantly reduced as compared to untreated controls (0.65 +/- 0.06 cm3 versus 1.63 +/- 0.12 cm3). About 50% of the animals in this group showed xenografts necrosis followed by complete regression of tumors by five months; (3) the combination of androgen ablation and 13-cis-RA treatment to nude mice carrying tumors showed synergistic effect in decreasing the tumor size. These results indicate that combination therapies based on androgen ablation and retinoid administration may be a useful approach for the treatment of prostate cancer.
Animals↗
Is heterozygous advantage necessary for polymorphism in one-locus two-allele systems?
This paper presents a model of density-dependent selection in a continuously reproducing diploid population with two alleles at one locus. Using differential equations, we assume that the fertility of a mating pair is determined exclusively by the female. Genotypic fitness is defined as the average contribution of an individual of the genotype to the total population growth rate. The conditions for protected polymorphism are derived, and the most interesting new result is that genetic polymorphism does not necessarily require heterozygote superiority in fitness in diallelic one-locus systems if both fertility and viability selection are simultaneously operating in the population.
Alleles↗
Transthoracic fine-needle aspiration biopsy cytology of pulmonary neoplasms.
The experience with 212 transthoracic fine-needle aspiration biopsy cytology specimens of mass lesions of the lung at a small Canadian hospital is reviewed. The technique showed a sensitivity of 78.0%, a specificity of 85.7%, a positive predictive value of 98.5%, and a negative predictive value of 25.0% when the cytological diagnoses were compared with the final clinicopathological diagnoses listed in the patients' charts. There was only one false positive diagnosis of malignancy. Diagnoses based on cytology of the aspirates were compared with histological diagnoses in 127 cases and the accuracy of typing of the major groups of carcinoma was assessed. Distinction between small-cell carcinoma and non-small-cell carcinoma was usually accurate and fairly good correlation was achieved for all major types of carcinoma. The results for typing of the neoplasm are not as good as those from larger centres in the world. The technique is considered to be useful even in the setting of a small hospital.
Biopsy, Needle↗
[Changes in soluble interleukin-2 receptor and its significance in nephrotic syndrome].
Serum and urine soluble interleukin-2 receptor (SIL-2R) levels were determined with ELISA method in 36 cases of nephrotic syndrome in order to investigate the significance of the change of SIL-2R level. The results showed the values in nephrotic stage group (n = 22) exceeded those in nephrotic stage remission group (n = 14, P < 0.01) and those in healthy controls (n = 20, P < 0.01). However, there was no difference of SIL-2R values either in serum or urine between nephrotic stage remission group and healthy controls (P > 0.05). Serum SIL-2R values were correlated with those of serum creatinine (r = 0.44, P < 0.01) and urine SIL-2R values were correlated with those of urine protein excretion (r = 0.48, P < 0.01). The study suggests that increased concentration of SIL-2R can serve as an indicator of nephrotic syndrome activation and/or exacerbation of renal dysfunction.
Adult↗
Properties and amino acid sequence of huwentoxin-I, a neurotoxin purified from the venom of the Chinese bird spider Selenocosmia huwena.
By means of reverse phase and ion-exchange high performance liquid chromatography, a neurotoxic peptide named huwentoxin-I was purified from the venom of the Chinese bird spider Selenocosmia huwena. The intraperitoneal and intracisternal LD50 in mice of the toxin were 0.70 mg/kg and 9.40 micrograms/kg, respectively. This toxin at the concentration of 1 x 10(-5) g/ml can irreversibly block the neuromuscular transmission of the isolated mouse phrenic nerve-diaphragm preparation in 13.4 +/- 1.3 min (mean +/- S.D., n = 5). The isoelectric point is 8.95 determined by isoelectric focusing electrophoresis. It consists of 33 amino acids including 6 Cys and 6 Lys determined by amino acid analysis. The complete amino sequence of huwentoxin-I was determined. The N-terminal and C-terminal residues were Ala and Leu, respectively. The primary structure showed partial homology with that of mu-agatoxins from the funnel-web spider Agelenopsis aperta.
Amino Acid Sequence↗
[Nephrocalcinosis and clinical significance in early chronic renal disease].
Kidney tissue calcium content from 33 diagnostic human renal biopsies was measured to assess tissue calcium concentration early in the course of human renal disease. Renal calcium content was correlated significantly with serum creatinine (r = 0.71, P < 0.001), serum phosphate (r = 0.64, P < 0.001), and serum Ca x P product (r = 0.66, P < 0.001), but not with serum calcium (r = -0.17, P > 0.05). Threefold greater calcium content was measured in biopsied tissue than in normal renal tissue (315 +/- 169 vs 69 +/- 17 mg/kg renal tissue, P < 0.001). The mean level of serum phosphate and Ca x P product was higher in the patients with significant renal function impairment (Ser > 115 mumol/L) than in patients with normal renal function (1.76 +/- 0.33 mmol/L vs 1.29 +/- 0.18 mmol/L, P < 0.001; 43 +/- 4.7 vs 33 +/- 4.5 mmol 2/L2, P < 0.001, respectively). The mean serum calcium levels were not different in the two groups (1.97 +/- 0.24 mmol/L vs 2.07 +/- 0.16 mmol/L, P > 0.05). The results suggest that renal calcium deposition begins early in the course of various renal diseases, and hence may accelerate progression of chronic renal failure the severity of renal calcium deposition is correlated with hyperphosphatemia and with the level of renal impairment. Dietary phosphate restriction may be necessary early in the course of renal disease.
Adult↗
Basic mycology underscoring medically important fungi.
This article details the basic mycologic features of yeast and mold-like fungi causing infections in humans. Concordant with the mycologic attributes delineating species identification, the pathogenic potential of mycotic agents is discussed with particular reference to intrinsic fungal virulence factors (e.g., exoenzymes) and host factors (e.g., neutrophil function, underlying disease) predisposing to colonization and infection.
Fungi↗
Diagnoses made by frozen-section examination of surgical specimens in a small Canadian hospital.
Examination of frozen sections, which is frequently used to make diagnoses at the Plains Health Centre, Regina, is expensive in terms of manpower and resources of the pathology department and should be used judiciously. The authors analysed the pathology records from January to December 1990 and found that more than 10% of surgical specimens were submitted for frozen-section diagnosis. A correct diagnosis was made in 94.8% of cases, and in approximately 1% of cases the diagnosis was deferred until paraffin sections were examined. An incorrect diagnosis by frozen-section examination was made in 4.2% of cases. In 13.2% of cases, frozen-section examination was apparently performed for reasons that were not medically legitimate. In a further 14.9% of cases the value of frozen-section examination was questionable. Clinicians need to be educated about the correct role of frozen-section examination in patient management, especially in this era of restricted hospital budgets.
Canada↗
[Synthesis of (+/-) demethoxy-eleutherol and (+/-) demethoxy-eleutherin].
(+/-) Demethoxy-eleutherol and (+/-) demethoxy-eleutherin were synthesized for studying the relationship between structure and coronary dilation activity. The structures of the two compounds and intermediates were confirmed by means of IR, MS and 1HNMR. Preliminary pharmacological experiments showed no activity for the two compounds.
Animals↗