Shear stress enhances microcin B17 production in a rotating wall bioreactor, but ethanol stress does not

Stress, including that caused by ethanol, has been shown to induce or promote secondary metabolism in a number of microbial systems. Rotating-wall bioreactors provide a low stress and simulated microgravity environment which, however, supports only poor production of microcin B17 by Escherichia coli ZK650, as compared to production in agitated flasks. We wondered whether the poor production is due to the low level of stress and whether increasing stress in the bioreactors would raise the amount of microcin B17 formed. We found that applying shear stress by addition of a single Teflon bead to a rotating wall bioreactor improved microcin B17 production. By contrast, addition of various concentrations of ethanol to such bioreactors (or to shaken flasks) failed to increase microcin B17 production. Ethanol stress merely decreased production and, at higher concentrations, inhibited growth. Interestingly, cells growing in the bioreactor were much more resistant to the growth-inhibitory and production-inhibitory effects of ethanol than cells growing in shaken flasks.

A multicentric study with arteether in patients of uncomplicated falciparum malaria

Two hundred and sixty seven patients of uncomplicated P. falciparum malaria completed study in a multicentric phase III clinical trial of Arteether. Arteether was given intramuscularly in a dose of 150 mg daily for three consecutive days. Each patient was followed upto 28 days of alpha, beta arteether therapy. The cure rate was 97% with fever clearance time between 1-7 days (24-168 hours) and parasite clearance time between 1-3 days (24-72 hours). Parasite reappearance rate was found to be 3% and reported at only three of the centres. Following the treatment no adverse effect was observed on haematological, biochemical and vital clinical parameters.

Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?

Sequencing of the Arabidopsis genome revealed a unique complexity of the plant heat stress transcription factor (Hsf) family. By structural characteristics and phylogenetic comparison, the 21 representatives are assigned to 3 classes and 14 groups. Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean. Evidently, this new type of Hsf is well expressed in different plant tissues. Besides the DNA binding and oligomerization domains (HR-A/B region), we identified other functional modules of Arabidopsis Hsfs by sequence comparison with the well-characterized tomato Hsfs. These are putative motifs for nuclear import and export and transcriptional activation (AHA motifs). There is intriguing flexibility of size and sequence in certain parts of the otherwise strongly conserved N-terminal half of these Hsfs. We have speculated about possible exon-intron borders in this region in the ancient precursor gene of plant Hsfs, similar to the exon-intron structure of the present mammalian Hsf-encoding genes.

Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?

Sequencing of the Arabidopsis genome revealed a unique complexity of the plant heat stress transcription factor (Hsf) family. By structural characteristics and phylogenetic comparison, the 21 representatives are assigned to 3 classes and 14 groups. Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean. Evidently, this new type of Hsf is well expressed in different plant tissues. Besides the DNA binding and oligomerization domains (HR-A/B region), we identified other functional modules of Arabidopsis Hsfs by sequence comparison with the well-characterized tomato Hsfs. These are putative motifs for nuclear import and export and transcriptional activation (AHA motifs). There is intriguing flexibility of size and sequence in certain parts of the otherwise strongly conserved N-terminal half of these Hsfs. We have speculated about possible exon-intron borders in this region in the ancient precursor gene of plant Hsfs, similar to the exon-intron structure of the present mammalian Hsf-encoding genes.

Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?

Sequencing of the Arabidopsis genome revealed a unique complexity of the plant heat stress transcription factor (Hsf) family. By structural characteristics and phylogenetic comparison, the 21 representatives are assigned to 3 classes and 14 groups. Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean. Evidently, this new type of Hsf is well expressed in different plant tissues. Besides the DNA binding and oligomerization domains (HR-A/B region), we identified other functional modules of Arabidopsis Hsfs by sequence comparison with the well-characterized tomato Hsfs. These are putative motifs for nuclear import and export and transcriptional activation (AHA motifs). There is intriguing flexibility of size and sequence in certain parts of the otherwise strongly conserved N-terminal half of these Hsfs. We have speculated about possible exon-intron borders in this region in the ancient precursor gene of plant Hsfs, similar to the exon-intron structure of the present mammalian Hsf-encoding genes.

Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?

Sequencing of the Arabidopsis genome revealed a unique complexity of the plant heat stress transcription factor (Hsf) family. By structural characteristics and phylogenetic comparison, the 21 representatives are assigned to 3 classes and 14 groups. Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean. Evidently, this new type of Hsf is well expressed in different plant tissues. Besides the DNA binding and oligomerization domains (HR-A/B region), we identified other functional modules of Arabidopsis Hsfs by sequence comparison with the well-characterized tomato Hsfs. These are putative motifs for nuclear import and export and transcriptional activation (AHA motifs). There is intriguing flexibility of size and sequence in certain parts of the otherwise strongly conserved N-terminal half of these Hsfs. We have speculated about possible exon-intron borders in this region in the ancient precursor gene of plant Hsfs, similar to the exon-intron structure of the present mammalian Hsf-encoding genes.

Influence of hypothyroid state on 45Ca(2+) influx and sensitivity of rat uterus to nifedipine and diltiazem

The influence of methimazole-induced hypothyroidism on spontaneous rhythmic contractions and Ca2+ channel function of rat uterus was examined. Hypothyroidism significantly reduced the amplitude and frequency of spontaneous rhythmic contractions. Nifedipine (10(-12)-10(-6) M) and diltiazem (10(-9)-10(-4) M) caused concentration-related inhibition of the myogenic responses of the oestrogenised rat uterus obtained from both eu- and hypothyroid rats. However, nifedipine was less potent (IC(50); 5.4 x 10(-9) M; n=6) in hypothyroid rat uterus as compared to euthyroid controls (IC(50): 8.13 x 10(-12) M; n=9) to inhibit the rhythmic contractions. Similarly, diltiazem was less potent (IC(50): 4.57 x 10(-6) M; n=9) to inhibit the uterine spontaneous contractions in hypothyroid than in euthyroid rat uterus (IC(50): 6.4 x 10(-8) M; n=6). A similar decrease in the sensitivity to nifedipine and diltiazem for reversal of K+ (100 mM)-induced tonic contraction was observed in uterus obtained from hypothyroid rats compared to the controls. Both nifedipine and diltiazem were less potent for causing concentration-related inhibition of K+-stimulated 45Ca2+ influx in uterine strips taken from the hypothyroid rats. Thus, the IC(50) values of nifedipine (1.83 x 10(-8) M; n=12) and diltiazem (1.8 x 10(-6) M; n=9) were significantly greater in tissues obtained from hypothyroid rats compared to the controls (IC(50) of nifedipine, 1.15 x 10(-11) M; n=12, diltiazem, 8.1 x 10(-8) M; n=8). Nifedipine-sensitive influx of 45Ca2+ - stimulated either by K+ (100 mM) or Bay k8644 (1,4-dihydro-2,6-dimethyl-5-nitro-4-[2'-(trifluromethyl)phenyl]-3-pyridine carboxylic acid methyl ester) (10(-8) M) was significantly less in uterine strips from hypothyroid rats compared to the controls. The results of the present study suggest that the inhibition of uterine rhythmic contractions may be attributable to a reduction in rat myometrial Ca2+ channel function in the hypothyroid state.

Role of surgery in the management of Graves' disease

Seventy-two patients, 50 women and 22 men, were operated on for Graves' disease. Their median age was 35 years. The indications for surgery included patients with large goitre, relapse after antithyroid drug (ATD) therapy, allergic reactions to ATD, non-compliance and finally an associated nodule with suspicion of carcinoma. Patients were rendered euthyroid with ATD before surgery and were pretreated with Lugol's iodine. Standard subtotal thyroidectomy was performed in 64 patients, total thyroidectomy in 7 patients, and one patient underwent a completion thyroidectomy after an initial subtotal thyroidectomy. The weight of the thyroid remnant on either side was estimated emperically between 3 g and 5 g. There was no postoperative death or thyrotoxic crisis. There was no case of permanent recurrent laryngeal nerve damage or hypoparathyroidism. Eight patients (11.1%) had temporary unilateral vocal cord palsy and 4 patients (5.5%) had temporary hypocalcemia. One patient (1.4%) developed recurrent hyperthyroidism. Postoperative transient hypothyroidism developed in 87.5% cases, all within the first postoperative year. The functional results at 2 years were as follows: Out of 47 cases followed 31 patients (65.9%) became euthyroid while 15 (31.9%) were still hypothyroid and requited long term substitutive treatment. Ophthalmopathy worsened in only one patient. Thyroidectomy has reasonable role in the management of Graves' disease, because the patients have had their diseases rapidly terminated, were hospitalised for an average period of only 3.5 days and have had no permanent functional insult except for hypothyroidism.

Total thyroidectomy for benign thyroid disorders in an endemic region

Total thyroidectomy is increasingly being accepted as a treatment of choice for differentiated thyroid cancer. However, because of presumed increased morbidity associated with this procedure, it is still not considered a viable option for management of benign thyroid disorders. To assess the safety and efficacy of total thyroidectomy for management of benign thyroid disorders, we analyzed our data from 127 total thyroidectomies performed for benign thyroid disorders. Demographic details, biochemical findings, indications for operation, specimen weight, and complications were noted. Among these patients, 52 had a toxic goiter and 75 had a nontoxic goiter. The mean duration of the goiters being present was 6.08 +/- 6.06 years (0.9--26.0 years), and the mean weight of the specimens was 136.88 +/- 120.68 g. The incidence of occult malignancy was 6.3% (n = 8), and those of permanent hypothyroidism and permanent recurrent laryngeal nerve palsy were 1.6% and 0.8%, respectively. Total thyroidectomy should be considered a treatment of choice for multinodular goiter and Graves' disease in a setting of palpable nodule(s) or ophthalmopathy (or both). It is particularly relevant in endemic regions where patients present with a long-standing, large nodular goiter with virtually no normal thyroid tissue. Reoperation for recurrent goiter in such a setting would be fraught with distressing complications.

Occult breast carcinoma: a report of four cases and review of literature

We report four occult carcinoma breast cases in which extensive axillary node metastases was the first manifestation. Upper outer quadrentectomy with axillary dissection was done in three patients while modified radical mastectomy was done in one. Primary tumor could be found in three patients, one had squamous cell carcinoma (SCC) & two had infiltrating duct carcinoma (IDC). However primary tumor was not detected in breast tissue of the fourth patient. Extensive lymph node metastases were found in three out of 14,15 out of 15(SCC), 24 out of 24 and 1 out of three axillary nodes respectively. Results of immunohistochemical staining for estrogen and progesterone receptors on three cases were negative. All patient received postoperative radiotherapy and chemotherapy. We have reviewed the literature and discussed the approach to diagnosis and management in female patients presenting with metastatic carcinoma in the axillary nodes with emphasis on the appropriate pre-treatment evaluation.

Regulation of elongation factor-1alpha expression by growth factors and anti-receptor blocking antibodies

The epidermal growth factor (EGF) family and its receptors regulate normal and cancerous epithelial cell proliferation, a process that could be suppressed by anti-receptor blocking antibodies. Polypeptide elongation factor-1alpha (EF-1alpha) is a multifunctional protein whose levels are positively correlated with the proliferative state of cells. To identify genes, whose expression may be modulated by anti-receptor blocking antibodies, we performed a differential display screening and isolated differentially expressed cDNAs. Isolates from one clone were 100% identical to human EF-1alpha. Both EGF and heregulin-beta1 (HRG) induced EF-1alpha promoter activity and mRNA and protein expression. Growth factor-mediated EF-1alpha expression was effectively blocked by pretreatment with humanized anti-EGF receptor antibody C225 or anti-human epidermal growth factor receptor-2 (HER2) antibody herceptin. Mutants and pharmacological inhibitors of p38(MAPK) and MEK, but not phosphatidylinositol 3-kinase, suppressed both constitutive and HRG-induced stimulation of EF-1alpha promoter activity in MCF-7 cells. Deletion analysis of the promoter suggested the requirement of the -393 to -204 region for growth factor-mediated transcription of EF-1alpha. Fine mapping and point mutation studies revealed a role of the SP1 site in the observed HRG-mediated regulation of the EF-1alpha promoter. In addition, we also provide new evidence to suggest that HRG stimulation of the EF-1alpha promoter involves increased physical interactions with acetylated histone H3 and histone H4. These results suggest that regulation of EF-1alpha expression by extracellular signals that function through human EGF receptor family members that are widely deregulated in human cancers and that growth factor regulation of EF-1alpha expression involve histone acetylation.

Detection and analysis of chromosomal arsenic resistance in Pseudomonas fluorescens strain MSP3

Pseudomonas fluorescens MSP3 isolated from sea water was resistant to arsenate. This bacterium harbored no plasmids, indicating that arsenic resistance was chromosomally encoded. The chromosomal DNA from MSP3 when transformed onto Escherichia coli DH5alpha using pBluescript exhibited resistance to sodium arsenate and sodium arsenite. Three clones MSA1, MSA2, and MSI3 containing the ars genes were obtained and further subcloning resulted in three fragments of size 2.2, 2.6, and 2.1 kb for pMSA11, pMSA12, and pMSI13, respectively, which contained the genes arsRBC of the arsenic operon. An efflux mechanism of detoxification was observed which was ATP dependent. The resistance mechanism was encoded from a single operon which consisted of an arsenite inducible repressor that regulates the expression of arsenate reductase (ars C) and inner membrane associated arsenite export system encoded by ars B. The chromosomal operon was cloned, sequenced, and found to consist of three cistrons, named as ars R, ars B, and ars C. Southern hybridization and mating experiments confirmed the functioning of the ars genes in the operon, thereby conferring increased resistance to sodium arsenate and sodium arsenite.

Squamous cell carcinoma of thyroid gland

We present the clinical manifestation, management and outcome in two cases of squamous cell cancer arising in the thyroid gland which is a rare entity. Both cases had advanced disease invading adjacent structures. At the followup of three to six months, one patient developed recurrence and died.

Functioning adrenal tumours in children and adolescents: an institutional experience

BACKGROUND

The purpose of the present paper was to carry out an audit of clinicopathological profile and treatment outcome in 13 children with functioning adrenal tumours.

METHODS

The medical records of 13 children with functioning adrenal tumours who were managed between June 1990 and January 1999 were reviewed. Demographic data, clinical features, biochemical and localization studies, operative details and follow-up records were studied. Children with neuroblastoma were excluded.

RESULTS

The mean age was 7.4 +/- 5.3 years. Seven patients had Cushing's syndrome (CS), two patients had virilizing tumours, three patients had phaeochromocytoma (PCC) and one patient had Conn's syndrome. All patients (except one child with CS) were treated surgically. Two children with adrenocortical carcinoma (ACCa) died during the perioperative period. Histopathological diagnosis was adrenal cortical adenoma (ACAd) in four patients, ACCa in five patients and PCC in three patients. Two ACCa patients died of metastases at 12 and 14 months, respectively, while the third is alive and well at 30 months. Children with ACAd are alive and well at 91, 56, 32 and 27 months postoperatively. Children with PCC are free of disease (normal urinary metanephrines) at 63, 18 and 8 months after surgery but require antihypertensive drugs in low doses.

CONCLUSION

The outcome of surgery is good in cases of ACAd and PCC. Although outcome is poor in ACCa, surgery remains the mainstay of treatment and offers good palliation.

Transcriptional repression of oestrogen receptor by metastasis-associated protein 1 corepressor

Activation of the heregulin/HER2 pathway in oestrogen receptor (ER)-positive breast-cancer cells leads to suppression of oestrogen-receptor element (ERE)-driven transcription and disruption of oestradiol responsiveness, and thus contributes to progression of tumours to more invasive phenotypes. Here we report the identification of metastatic-associated protein 1 (MTA1), a component of histone deacetylase (HDAC) and nucleosome-remodelling complexes, as a gene product induced by heregulin-beta1 (HRG). Stimulation of cells with HRG is accompanied by suppression of histone acetylation and enhancement of deacetylase activity. MTA1 is also a potent corepressor of ERE transcription, as it blocks the ability of oestradiol to stimulate ER-mediated transcription. The histone-deacetylase inhibitor trichostatin A blocks MTA1-mediated repression of ERE transcription. Furthermore, MTA1 directly interacts with histone deacetylase-1 and -2 and with the activation domain of ER-alpha. Overexpression of MTA1 in breast-cancer cells is accompanied by enhancement of the ability of cells to invade and to grow in an anchorage-independent manner. HRG also promotes interaction of MTA1 with endogenous ER and association of MTA1 or HDAC with ERE-responsive target-gene promoters in vivo. These results identify ER-mediated transcription as a nuclear target of MTA1 and indicate that HDAC complexes associated with the MTA1 corepressor may mediate ER transcriptional repression by HRG.