A unique variant of a homeobox gene related to Drosophila cut is expressed in mouse testis

The wild-type gene encoding granule-bound starch synthase (GBSS) is capable of both complementing the amylose-free (amf) potato mutant and inhibiting the endogenous GBSS gene expression in wild-type potato. Co-suppression of the endogenous GBSS gene, easily visualised by staining the starch with iodine, occurred when the full-size GBSS sequence (genomic), GBSS cDNA or even the mutant amf allele were introduced into the wild-type potato. Conversely, introduction of the GBSS promoter sequence alone, did not result in co-suppression in the 80 analysed transformants. Neither the orientation of the GBSS gene with respect to kanamycin resistance nor the presence of an enhancer influenced the frequency of plants showing a co-suppression phenotype. After crossing a partially complemented amf mutant with a homozygous wild-type plant, the F1 offspring segregated into plant phenotypes with normal and decreased expression of the GBSS gene. This decreased expression correlated with the presence of a linked block of five T-DNA inserts which was previously shown to be correlated with partial complementation of the amf mutant. This crossing experiment indicates that co-suppression can cause inhibition of gene expression of both inserted and endogenous wild-type GBSS genes. The frequency of partially complemented amf plants was equal to the frequency of co-suppressed wild types when a construct, with an enhancer in front of the GBSS promoter, was used (pWAM 101E). This might suggest that partial complementation of the amf genotype caused by unstable expression of the transgene can be overcome by inserting an enhancer in front of the GBSS promoter.     

Factors influencing incidence and extension of metachronous liver metastases of colorectal adenocarcinoma. A multivariate analysis

BACKGROUND/AIM: Three hundred and eighty-seven patients surgically treated for colorectal adenocarcinoma were assessed by a multivariate analysis and the factors influencing incidence and extension of metachronous liver metastases studied. METHODOLOGY: A series of 387 patients which had been surgically treated for colorectal adenocarcinoma between January 1980 to December 1990 and followed-up over a minimum of a 5-year period was retrospectively studied. RESULTS: The most reliable prognostic markers are represented by tumor site (p < 0.05) and, more specifically, by wall infiltration (p < 0.01) and metastatic lymph-nodes (p < 0.05). The only independent variable with a significant impact on stage of metachronous liver metastases was proved to be the depth of wall infiltration (p < 0.05). CONCLUSION: This study confirms the reliability of some indicators of primary tumor in influencing incidence, but not extension, of metachronous liver metastases and this is the main problem when it comes to using prognostic factors in order to modulate the intervals of postoperative follow-up according to risk category.     

Treatment of depression by obstetrician-gynecologists: a survey study

OBJECTIVE: We performed an exploratory survey of depression diagnosis, treatment, and patient referral patterns by Fellows of ACOG. We also examined obstetrician-gynecologists' professional training in the management of clinical depression. METHODS: We sent a questionnaire to a total of 1370 ACOG Fellows. Sixty percent of the surveys were returned. RESULTS: As a group, obstetrician-gynecologists reported diagnosing an average of four new cases of depression per month. Within the overall sample, the number of new diagnoses of depression made each month was significantly greater for those defining themselves as primary care physicians than for those defining themselves as specialists. When treating depression pharmacologically, obstetrician-gynecologists reported that they overwhelmingly (74% of the time) chose selective serotonin reuptake inhibitor antidepressants. Ninety-five percent of obstetrician-gynecologists reported that they referred severely depressed patients to a mental health professional. A majority of respondents neither received residency training (80%) nor completed a continuing medical education course (60%) on the treatment of clinical depression in women. CONCLUSION: Obstetrician-gynecologists who describe themselves as primary care physicians make significantly more diagnoses of depression than those considering themselves specialists. Studies further to assess obstetrician-gynecologists' management of depression and better to define needs for professional education are warranted.     

Regulation of transcription in mammalian cells by yeast Leu3p and externally supplied inducer

We have studied the properties of two new fluorescent probes, 7-dimethylaminocoumarin derivatives, 4-[N, N-dimethyl-N-(n-tetradecyl)ammoniummethyl]-7-(N,N-dimethylamino)co umarin chloride (TAMAC) and 4-(n-dodecylthiomethyl)-7-(N,N-dimethylamino)coumarin (DTMAC) in model membrane systems. Both probes are sensitive to solvent polarity. The TAMAC probe has a quaternary ammonium function to position it at a fixed location with respect to the membrane interface. In membranes of dipalmitoleoylphosphatidylethanolamine (DiPoPE), both probes detect marked increases in surface hydrophobicity as the bilayer to hexagonal phase transition temperature is approached. This does not occur when the probes are embedded in dipalmitoleoylphosphatidylcholine (DiPoPC) in which case the fluorescence emission is found to be largely independent of temperature. A nitroxide quencher covalently linked to the 5 position of the sn-2 acyl chain of phosphatidylcholine quenches the fluorescence of DTMAC in DiPoPC more than in DiPoPE, indicating the deeper insertion of this probe in DiPoPC. As the temperature is increased the DTMAC fluorophore moves even further out of the membrane. These findings indicate that DTMAC, which does not contain a group to fix its location along the bilayer normal, adjusts its position to small changes in environment polarity, so as to maintain an environment of a fixed dielectric constant. However, with greater changes in membrane interfacial polarity the environment of the probe will be altered. Thus, in addition to the sensitivity of these probes to solvent polarity, the ability of a fixed nitroxide to quench DTMAC becomes another parameter with which to characterize membrane properties with these probes.     

Microstructural development of ZnO varistor during reactive liquid phase sintering

The microstructural evolution, grain growth and densification for the varistor systems ZnO-Bi₂O₃ (ZB), ZnO-Bi₂O₃-Sb₂O₃ (ZBS), ZnO-Bi₂O₃-Sb₂O₃-MnO-Cr₂O₃-CoO (ZBSCCM) were studied using constant heating rate sintering, scanning electron microscopy (SEM) andin situ phase formation measurement by high temperature X-ray diffraction (HT-XRD). The results showed that the densifying process is controlled by the formation and decomposition of the Zn₂Bi₃Sb₃O₁₄ pyrochlore (PY) phase for the ZBS and ZBSCCM systems. The addition of transition metals (ZBSCCM system) alters the formation and decomposition reaction temperatures of the pyrochlore phase and the morphology of the Zn₇Sb₂O₁₂ spinel phase. Thus, the spinel grains act as inclusions and decrease the ZnO grain growth rate. Spinel grain growth kinetics in the ZBSCCM system showed ann value of 2.6, and SEM and HT-XRD results indicate two grain growth mechanisms based on coalescence and Ostwald ripening.     

Biological verification of fluid-to-particle interfacial heat transfer coefficients in a pilot scale holding tube simulator

Mesothelioma is a malignant pleural or intraperitoneal tumor attributable to asbestos exposure in more than 80% of the cases. Manganese superoxide dismutase (MnSOD), a mitochondrial superoxide radical scavenging enzyme, is low in most tumors but is known to be induced by asbestos fibers and certain cytokines. Induction of MnSOD may be associated in asbestos-related pulmonary diseases in vivo. We investigated here MnSOD specific activity and MnSOD mRNA level using healthy human lung tissue, SV40-transformed human pleural mesothelial cells (Met5A), and six human malignant mesothelioma cell line cells. Total SOD (CuZnSOD + MnSOD) and MnSOD activities were 20.0 +/- 4.8 U/mg protein and 3.2 +/- 1.2 U/mg protein in healthy human lung tissue, and 25.6 +/- 10.7 U/mg and 3.8 +/- 1.0 U/mg in Met5A cells, respectively. In four mesothelioma cell lines MnSOD activity was significantly elevated, the highest activity (30.1 +/- 8.2 U/mg) was almost 10-fold compared to the activity in Met5A cells. The steady state mRNA level of MnSOD was low in Met5A cells and markedly higher in all mesothelioma cell lines roughly in proportion with enzyme activities. Cytotoxicity experiments, which were conducted in four cell lines, indicated that cells containing high MnSOD mRNA level and activity were resistant to the mitochondrial superoxide-producing agent menadione. In conclusion, our results suggest that human mesothelioma may express high levels of MnSOD, which is associated with high oxidant resistance of these cells.     

Jejuno-ileal bypass, enteric hyperoxaluria, and oxalate nephrosis: a role for polarised light in the renal biopsy

Enteric hyperoxaluria, a complication of jejuno-ileal bypass, is associated with renal failure owing to oxalate nephrosis or tubulo-interstitial nephritis. A 54 year old woman developed renal failure 17 months after jejuno-ileal bypass for morbid obesity. Renal biopsy showed widespread acute on chronic damage to the tubulo-interstitial compartment with extensive deposition of oxalate crystals. The extent of oxalate deposition was only evident on polarisation of the biopsy.     

Colorectal cancer in the young patient

Although predominantly a disease of older adults, colorectal cancer affects the younger population with an incidence of two to six per cent. It is thought to carry a less favorable prognosis in the young than in the general population. This may be due to advanced stage of the tumor at diagnosis. This study is composed of 37 patients, aged 40 and younger, treated over a 20-year period for colorectal cancer at Louisiana State University Medical Center-Shreveport and E. A. Conway Hospital. It was performed to investigate the incidence, stage at diagnosis, and prognosis of colorectal cancer in these young patients. The location of the primary tumor was fairly evenly distributed throughout the colon and rectum in this population. Pain, weight loss, rectal bleeding, and nausea and vomiting were the most common presenting symptoms. A family history of colon cancer or premalignant lesions were not risk factors in this study. Seventy per cent of all patients were treated with curative intent, and 42 per cent of these patients developed recurrent disease. The patients in this review presented with a higher incidence of advanced disease. Thirty-seven per cent of the lesions were Duke's C and 22 per cent were Duke's D, with poor 5-year survival (11% and 0%, respectively) when compared with national studies. The absolute 5-year survival for all young patients with colorectal cancer was 26 per cent (5 of 19 patients). It is important for the surgeon to be aware of the potential for colorectal cancer in young patients and to take an aggressive approach to the diagnosis and early treatment of the disease.