Functional domains of the transcriptional activator NUC-1 in Neurospora crassa

The NUC-1 regulatory protein directly controls the transcription of these genes and how the activity enzymes in Neurospora crassa. To understand how NUC-1 regulates the transcription of these genes and how the activity of NUC-1 is modulated by other regulatory proteins, two putative functional domains of NUC-1 were analysed: the DNA-binding domain and the regulatory domain. The DNA-binding activity of NUC-1 has not been directly demonstrated; however, results of deletion analysis, sequence analysis of the nuc-1 mutant alleles, and strong sequence similarity with the Saccharomyces cerevisiae PHO4 protein strongly suggest that the basic helix-loop-helix motif of NUC-1 forms a DNA-binding domain. Deletion and mutant analyses revealed that 39 amino acid (aa) residues (aa 463 to 501), or fewer, of NUC-1 are interacting with the negative regulatory factor(s), the PREG and/or PGOV proteins.

Histologic regression in malignant melanoma: an interobserver concordance study

Histologic evidence for regression as a prognostic indicator in melanoma has shown conflicting results. To assess if melanoma regression is a consistently identifiable histologic feature, an interobserver concordance study was undertaken. Fifty histologic slides of melanoma with Breslow thickness of 1 mm or less were non-randomly selected from the Massachusetts General Hospital Melanoma Registry. The selection was in favor of those with regression present in 44 of 50 slides (88%). Two dermatopathologists working independently evaluated a 2 mm wide bracketed area in each tissue section and then the remainder of the non-bracketed tissue section for regression. Before and after each slide review, the evaluators were required to read criteria for early, intermediate, and late regression explicitly outlined. The overall concordance rate for the presence and absence of regression was 96% (48/50) in the bracketed area and 90% for the outside area. When the group with regression was subdivided into three stages, interobserver agreement fell to 86% for the bracketed, and 66% for the outside area. In at least 30% of cases where regression was detected in the bracketed area, both reviewers observed two or more stages of regression in the remainder of tissue section. Therefore, subdividing the process is impractical and unrealistic. Consistent histologic identification of regression in melanoma requires a simple and systematic approach which should be applied to future studies that include melanoma regression as a prognostic factor.

Determination of the rate of cerebral oxygen consumption and regional cerebral blood flow by non-invasive 17O in vivo NMR spectroscopy and magnetic resonance imaging. Part 2. Determination of CMRO2 for the rat by 17O NMR, and CMRO2, rCBF and the partition coefficient for the cat by 17O MRI

The rate of oxygen consumption (CMRO2) in intact rat and cat brains was calculated by novel data analysis methods from data obtained in in vivo 17O NMR spectroscopy and imaging inhalation studies. Data analysis methods of 17O inhalation measurements are applied to the calculation of CMRO2, regional cerebral blood flow (rCBF), the reflow (R), the arterial venous difference (AVD) and the partition coefficient (lambda). Several of the applied methods for the determination of CMRO2 do not require measurements of regional cerebral blood flow and H2 17O arterial concentration. The proposed methods have been tested, and the results obtained by the different methods are in very good agreement. It is shown that 17O NMR is unique in providing the rate of blood water flow, where the natural abundance 17O NMR signal consists of an internal reference and that lambda is essentially 1. The average values of CMRO2 for rats and cats were found to be 2.09 +/- 0.35 and 1.18 +/- 0.58 (mumol/O2/g tissue)/min, respectively. The average value for rCBF for the cat was found to be 0.38 +/- 0.12 [(mg/g)/min]. The average value for lambda was found to be 1.00 +/- 0.04. The ratio of AVD due to organs other than the brain to AVD due to the brain is smaller than 1 for the rat and the cat. The time and spatial resolution accuracy of the spectroscopic and imaging methods are compared, discussed and statistically analysed. It is concluded that the accuracy of determination of CMRO2 for the rat is higher than for the cat by a factor of 8.

Insertional mutagenesis in Neurospora crassa: cloning and molecular analysis of the preg+ gene controlling the activity of the transcriptional activator NUC-1

The transcriptional activator NUC-1 controls the transcription of the genes for phosphorus acquisition enzymes, and its activity is regulated by the negative regulatory factors, PREG and PGOV In this report, we describe the cloning and molecular analysis of the preg+ gene. In Neurospora crassa, as in higher eukaryotes, transformation frequently results in nonhomologous integration of transforming DNA. Insertion of transforming DNA into host genes mutates the gene and provides a molecular tag for cloning it. We obtained two mutants that have an insertion in the preg+ and pgov+ genes, respectively, among 2 x 10(5) transformants. The preg+ gene was cloned by screening a Neurospora genomic DNA library with DNA sequences flanking the transforming DNA of the rescued plasmid. Northern analysis showed that the transcription of the preg+ gene is not regulated by phosphate. The carboxy-terminal half of PREG shows strong homology with Saccharomyces cerevisiae PHO80 whose function is analogous to that of PREG. The pregc mutations are located in the well conserved residues which may directly interact with the residues in the regulatory domain of NUC-1.

Clinical diagnosis of pigmented lesions using digital epiluminescence microscopy. Grading protocol and atlas

BACKGROUND AND DESIGN

Epiluminescence microscopy (ELM) is a clinical technique that permits in vivo visual inspection of pigmented anatomic structures of the epidermis, dermoepidermal junction, and papillary dermis. A protocol is proposed for systematic visual inspection of pigmented lesions. Seventy pigmented lesions were imaged with a digital ELM camera system. Images were visually inspected for eight "global" ELM features, 23 "local" ELM features, and 18 network features. An atlas of the most clinically significant ELM features is presented with pilot estimates of their sensitivity and specificity for detecting melanoma.

RESULTS

Preliminary data suggest that ELM features that may be most specific for melanoma include multicomponent pattern, nodular pattern, pseudopods, radial streaming, blue-gray areas, whitish veil (milky way), and sharp network margins. Epiluminescence microscopic features that may be most sensitive for melanoma include pigment dots, peripheral erythema, peripheral dark network patches, marked mean network irregularity, network line thickness variability, radial streaming, blue-gray areas, and whitish veil (milky way). Epiluminescence microscopic features that may be most sensitive for severe melanocyte atypia include pigment dots, peripheral erythema, hypopigmented network patches, peripheral dark network patches, marked mean network irregularity, and focal absence of network. In addition, features that may have a very high specificity for benign lesions include saccular pattern (suggests hemangioma), globular pattern (suggests a compound or dermal nevus), and multiple comedolike openings (suggests seborrheic keratosis).

CONCLUSIONS

Features most sensitive for severe atypia and melanoma could form the basis for a screening test for considering biopsy. Features most specific for melanoma then could be applied to further triage management of pigmented lesions that meet initial screening criteria. In addition, features with very high specificity for benign lesions may help develop ELM criteria to avoid unnecessary surgery.

Lymphotropic papovavirus transforms hamster cells without altering the amount or stability of p53

Expression of the early regions of several primate polyomaviruses (SV40, BKV, JCV, and LPV) in hamster cells induces transformation, manifested by the ability to grow in soft agar. Hamster cells transformed by SV40 contain complexes between the SV40 T antigen and the cellular tumor suppressor protein p53. We detected analogous complexes between p53 and the BKV T antigen in hamster cells transformed by the BKV early region, where the half life of p53 increased 16-fold. However, neither a LPV-transformed hamster fibroblast cell line [LPV-HE (F); K. K. Takemoto and T. Kanda, 1984, J. Virol. 50, 100-105] nor BHK-21 cells transformed by the LPV early region contained detectable complexes between the LPV T antigen and p53, nor was the stability of p53 in LPV transformed BHK-21 cells altered. Association between hamster p53 and the LPV T antigen expressed as glutathione S-transferase fusion protein could not be detected in vitro. These data indicate that alteration of the amount or stability of p53 is not required for transformation of hamster cells by LPV. However, as viruses such as SV40 and BKV whose T antigens bind p53 are oncogenic in hamsters, whereas LPV is not, the alteration of p53 amount or stability may be required for tumorigenesis.

Adrenal steroid receptor activation in rat brain and pituitary following dexamethasone: implications for the dexamethasone suppression test

The dexamethasone suppression test (DST) has been used extensively to evaluate feedback inhibition of the hypothalamic-pituitary-adrenal (HPA) axis by adrenal steroids. Nevertheless, it remains unclear at what level of the HPA axis and through which adrenal steroid receptor subtype dexamethasone exerts its inhibitory effect. Because adrenal steroid receptor activation is an important prerequisite for dexamethasone to affect cellular function, HPA axis tissues that exhibit evidence of receptor activation following dexamethasone administration are likely site(s) of action for this synthetic hormone to inhibit HPA axis activity. Therefore, type-I and type-II adrenal steroid receptor activation was assessed in the pituitary, hypothalamus, and hippocampus of intact and adrenalectomized rats after overnight exposure to various oral doses of dexamethasone. Results with dexamethasone were compared to similar studies using corticosterone, the endogenous glucocorticoid of the rat. All dexamethasone doses led to significant type-II receptor activation in the pituitary, whereas only an exceedingly high dexamethasone dose activated type-II receptors in the hippocampus and hypothalamus. Dexamethasone had little effect on type I receptors in any tissue at any dose. In contrast, corticosterone significantly activated type-I receptors in all tissues, whereas it activated type-II receptors in the brain and not the pituitary at physiological concentrations. Because dexamethasone activated pituitary type-II receptors at blood concentrations that did not activate type-II receptors in the brain, these results suggest that the DST in humans may primarily be a measure of type-II adrenal steroid receptor feedback inhibition at the level of the pituitary.

Central non-Pur.Pyr sequences in oligo(dG.dC) tracts and metal ions influence the formation of intramolecular DNA triplex isomers

The effect of the central non-Pur.Pyr sequences in oligo(dG.dC) inserts on determining the type of intramolecular DNA triplex isomers formed in negatively supercoiled plasmids was investigated. Different triplex types (H-r3, H-r5, and H-y3), revealed by a combination of chemical probing and Maxam-Gilbert sequencing reactions, were adopted by the oligo(dG.dC) tracts depending on the length and composition of the central non-Pur.Pyr sequences (0, 3, or 5 base pairs) and the kind of metal ions. The H-r3 triplex conformer, one isomer of a Pur.Pur.Pyr structure, was formed in the (C)20 and (C)10GCG(C)10 inserts in plasmids in the presence of certain metal ions. Interestingly, H-r5, the other isomer of the Pur.Pur-Pyr triplex which had not been detected previously, was formed in a (C)9GAATT(C)9 insert in the presence of either Mg2+ or Ca2+. Alternatively, H-y3, one isomer of a Pyr.Pur.Pyr triplex, was formed in the (C)9GAATT(C)9 insert in the absence of metal ions. Thus, central non-Pur.Pyr sequences and metal ions play a role as determinants of the types of intramolecular triplexes formed; they also reduce the requirement of longer Pur.Pyr repeat sequences to form intramolecular triplexes. Furthermore, the effects of MgCl2 concentration and pH on the formation of triplex isomers were examined. The Pur.Pur.Pyr conformations (H-r3 and H-r5) may be the favored conformations in the cellular milieu, since they are stable at physiological pH and metal ion concentration.

Multiple primary cutaneous melanomas

BACKGROUND

Development of multiple primary cutaneous melanomas is a well-recognized phenomenon. As with single primary melanoma, personal and family histories of melanoma and dysplastic nevi (DN) are considered important risk factors. The natural history and impact of regular follow-up evaluation of this entity were examined.

METHOD

Through a search of the computerized data bank of the Pathology Department and the Melanoma Registry of the Pigmented Lesion Clinic at Massachusetts General Hospital, 41 patients with multiple cutaneous melanomas were identified.

RESULTS

Mean (+/- standard error) age at first diagnosis was 49 +/- 2 years (range, 21-75 years). The male to female ratio was 2:1. The median number of primary melanomas was two (88%). Three patients had three and one had five. Melanoma types included superficial spreading (70%), nodular (8%), lentigo maligna (2%), and unclassified (10%), and in 7% the type was unknown. Nineteen (46%) patients had histologic and/or clinical evidence of DN. For the group with DN, the mean age at first diagnosis (44 +/- 3 years) was significantly less than that of patients without DN (54 +/- 3 years) (P less than 0.05). Family history of melanoma was found in 10 patients (24%). Multiple melanomas were diagnosed concurrently in 16 patients (39%), whereas in 25 (61%) diagnosis was sequential. For the latter group, the mean tumor thickness from the first (1.21 +/- 0.28 mm) to the second melanoma (0.51 +/- 0.08 mm) decreased significantly (P less than 0.05); the median time interval was 36 months (range, 2-372 months).

CONCLUSION

These data confirm the need for complete skin examination for patients with newly diagnosed melanoma; and, with subsequent melanomas appearing as long as 31 years after the first melanoma, continued follow-up with complete skin examinations seems prudent.

GC-rich flanking tracts decrease the kinetics of intramolecular DNA triplex formation

The effect of the base composition of flanking sequences on DNA intramolecular triplex formation was investigated in negatively supercoiled plasmids. The rates of triplex formation at two oligopurine.oligopyrimidine inserts with interrupting sequences in plasmids containing AT- or GC-rich flanking sequences were compared as a function of temperature, pH, and negative superhelical density. The kinetics of the transition of linear B-DNA to triplex (also called H-DNA) were influenced by all of these factors; triplexes were formed slower in a GC-rich background than in an AT-rich background. However, at equilibrium, the same amounts of the triplexes in AT- or GC-rich contexts were formed, and the conformations adopted by (GAA)4TTCGC(GAA)4 showed the canonical intramolecular triplex as mapped with chemical probes. We propose that the GC-rich segments caused this effect by thermodynamically clamping the DNA inserts, since the dependence of kinetics on base composition disappeared in tetraalkylammonium ions which eliminate the dependence of helix-coil transitions on base composition. The dependence of the kinetics of intramolecular triplex formation on flanking sequences further strengthens the concept of the role of DNA as a dynamic participant in cellular events.

[Isolation and identification of julibrotriterpennoidal lactone A from Albizia julibrissin Durazz]

Julibrotriterpennoidal lactone A was isolated from the cortex of Albizia julibrissin. Its structure (the C28----C21 lactone of, 3 beta, 16 beta, 21 beta-trihydroxy-delta 12-oleanen-28-oic acid) has been determined on the basis of spectral evidence (IR, 1HNMR, 13C NMR and MS).

Primary malignant melanoma of the external auditory canal: a case report with presentation as an aural polyp

A case of primary cutaneous melanoma of the external auditory canal and a review of the literature are reported. This is the first reported case with microstaging of the tumor. The tumor presented as a polypoid obstructive lesion of the external ear canal. Although occurrence of melanoma in this location is extremely rare, differential diagnosis of an external ear canal polyp should be expanded to include primary malignant melanoma.

[Chemical constituents of Rhodiola kirilowii (Reg.) Reg]

Three compounds were isolated from the water-soluble part of alcohol extracts of rhizomes of Rhodiola kirilowii. Two of them were identified as salidroside and tyrosol, respectively by chemical and spectral analysis. beta-sitosterol was obtained from the petroleum extracts of the plant.

Subcutaneous insulin absorption explained by insulin's physicochemical properties. Evidence from absorption studies of soluble human insulin and insulin analogues in humans

OBJECTIVE

To study the influence of molecular aggregation on rates of subcutaneous insulin absorption and to attempt to elucidate the mechanism of absorption of conventional soluble human insulin in humans.

RESEARCH DESIGN AND METHODS

Seven healthy male volunteers aged 22-43 yr and not receiving any drugs comprised the study. This study consisted of a single-blind randomized comparison of equimolar dosages of 125I-labeled forms of soluble hexameric 2 Zn2+ human insulin and human insulin analogues with differing association states at pharmaceutical concentrations (AspB10, dimeric; AspB28, mixture of monomers and dimers; AspB9, GluB27, monomeric). After an overnight fast and a basal period of 1 h, 0.6 nmol/kg of either 125I-labeled human soluble insulin (Actrapid HM U-100) or 125I-labeled analogue was injected subcutaneously on 4 separate days 1 wk apart. Absorption was assessed by measurement of residual radioactivity at the injection site by external gamma-counting.

RESULTS

The mean +/- SE initial fractional disappearance rates for the four preparations were 20.7 +/- 1.9 (hexameric soluble human insulin), 44.4 +/- 2.5 (dimeric analogue AspB10), 50.6 +/- 3.9 (analogue AspB28), and 67.4 +/- 7.4%/h (monomeric analogue AspB9, GluB27). Absorption of the dimeric analogue was significantly faster than that of hexameric human insulin (P less than 0.001); absorption of monomeric insulin analogue AspB9, GluB27 was significantly faster than that of dimeric analogue AspB10 (P less than 0.01). There was an inverse linear correlation between association state and the initial fractional disappearance rates (r = -0.98, P less than 0.02). Analysis of the disappearance data on a log linear scale showed that only the monomeric analogue had a monoexponential course throughout. Two phases in the rates of absorption were identified for the dimer and three for hexameric human insulin. The fractional disappearance rates (%/h) calculated by log linear regression analysis were monomer 73.3 +/- 6.8; dimer 44.4 +/- 2.5 from 0 to 2 h and 68.9 +/- 3.5 from 2.5 h onward; and hexameric insulin 20.7 +/- 1.9 from 0 to 2 h, 45.6 +/- 5.0 from 2.5 to 5 h, and 70.6 +/- 6.3 from 5 h onward.

CONCLUSIONS

Association state is a major determinant of rates of absorption of insulin and insulin analogues. The lag phase and the subsequent increasing rate of subcutaneous soluble insulin absorption can be explained by the associated state of native insulin in pharmaceutical formulation and its progressive dissociation into smaller units during the absorption process.

Absorption kinetics and action profiles of subcutaneously administered insulin analogues (AspB9GluB27, AspB10, AspB28) in healthy subjects

OBJECTIVE

The subcutaneous absorption and resulting changes in plasma insulin or analogue, glucose, C-peptide, and blood intermediary metabolite concentrations after subcutaneous bolus injection of three soluble human insulin analogues (AspB9GluB27, monomeric; AspB28, mixture of monomers and dimers; and AspB10, dimeric) and soluble human insulin were evaluated.

RESEARCH DESIGN AND METHODS

Fasting healthy male volunteers (n = 7) were studied on five occasions 1 wk apart randomly receiving 0.6 nmol.kg-1 s.c. 125I-labeled AspB10 or soluble human insulin (Novolin R, Novo, Copenhagen); 1st study and 0.6 nmol.kg-1 s.c. 125I-labeled AspB28, AspB9GluB27 or soluble human insulin (2nd study). Residual radioactivity at the injection site was measured over 8 h with frequent venous sampling for plasma immunoreactive insulin or analogue, glucose, C-peptide, and blood intermediary metabolite concentrations.

RESULTS

The three analogues were absorbed 2-3 times faster than human insulin. The mean +/- SE time to 50% residual radioactivity was 94 +/- 6 min for AspB10 compared with 184 +/- 10 min for human insulin (P less than 0.001), 83 +/- 8 min for AspB28 (P less than 0.005), and 63 +/- 9 min for AspB9GluB27 (P less than 0.001) compared with 182 +/- 21 min for human insulin. delta Peak plasma insulin analogue levels were significantly higher after each analogue than after human insulin (P less than 0.005). With all three analogues, the mean hypoglycemic nadir occurred earlier at 61-65 min postinjection compared with 201-210 min for the reference human insulins (P less than 0.005). The magnitude of the hypoglycemic nadir was greater after AspB9GluB27 (P less than 0.05) and AspB28 (P less than 0.001) compared with human insulin. There was a significantly faster onset and offset of responses in C-peptide and intermediary metabolite levels after the analogues than after human insulin (P less than 0.05).

CONCLUSIONS

The rapid absorption and biological actions of these analogues offer potential therapeutic advantages over the current short-acting neutral soluble insulins.

[The qualitative and quantitative analyses of protein with a novel fluorescence agent (EPQS) by fluorescent scanning on solid substrate]

We synthesized a new fluorescence agent, EPQS, which could be soluble in water and was stable in the analytical process. It was characteristic of good fluorescence parameters. Human serum albumin (HSA) was marked with EPQS and purified by the paper electrophoresis dialysis. We determined the fluorescent spectra and excitation spectra of the marked HSA, or EPQS on the cellulose acetate paper by RF-510 fluorescence spectrophotometer-thin-layer chromatoscanner. The former lambda ex = 370nm lambda em = 470nm; the latter lambda ex = 382nm lambda em = 476 nm. Then we touched different quantity of EPQS-HSA upon the cellulose acetate. The fluorescent scanning on the paper disclosed that the relationship between the quantity adopted and the fluorescence intensity is linear. These showed that the protein could be quickly determined qualitatively and quantitatively by this simple method, and EPQS was useful.

Comparison of subcutaneous soluble human insulin and insulin analogues (AspB9, GluB27; AspB10; AspB28) on meal-related plasma glucose excursions in type I diabetic subjects

OBJECTIVE

To compare postprandial glucose excursions and plasma free insulin-analogue levels after subcutaneous injection of three novel human insulin analogues (AspB10; AspB9, GluB27; and AspB28) with those after injection of soluble human insulin (Actrapid HM U-100).

RESEARCH DESIGN AND METHODS

Six male subjects with insulin-dependent diabetes, at least 1 wk apart and after an overnight fast and basal insulin infusion, received 72 nmol (approximately 12 U) s.c. of soluble human insulin 30 min before, or 72 nmol of each of the three analogues immediately before, a standard 500-kcal meal.

RESULTS

Mean basal glucoses were similar on the 4 study days. Compared to human insulin (6.3 +/- 0.8 mM), mean +/- SE peak incremental glucose rises were similar after analogues AspB10 (5.4 +/- 0.8 mM) and AspB9, GluB27 (5.4 +/- 0.7 mM) and significantly lower after analogue AspB28 (3.6 +/- 1.2 mM, P less than 0.02). Relative to soluble human insulin (100% +/- SE21), incremental areas under the glucose curve between 0 and 240 min were 79% +/- 34 (AspB10, NS), 70% +/- 29 (AspB9, GluB27, NS), and 43% +/- 23 (AspB28, P less than 0.02). Basal plasma free insulin levels were similar on the 4 study days. Plasma free insulin-analogue levels rose rapidly to peak 30 min after injection at 308 +/- 44 pM (AspB10); 1231 +/- 190 pM (AspB9, GluB27) and 414 +/- 42 pM (AspB28) and were significantly higher than corresponding (i.e., 30 min postmeal) plasma free insulin levels of 157 +/- 15 pM (P less than 0.02 in each case).

CONCLUSIONS

Plasma profiles of the insulin analogues were more physiological than that of human insulin after subcutaneous injection. All three analogues given immediately before the meal are at least as effective as soluble human insulin given 30 min earlier. These analogues are promising potential candidates for short-acting insulins of the future.

Prognosis after initial recurrence of cutaneous melanoma

We reviewed 231 patients who developed recurrent disease 1 to 218 months after surgical therapy for clinical stage I cutaneous melanoma. Metastatic lesions amenable to surgery, including visceral recurrences, were resected. Adjuvant systemic chemotherapy/immunotherapy or regional hyperthermic perfusion was added in patients with unresected disease. Local irradiation was employed for nonresectable brain or other isolated symptomatic metastases. The overall 5-year survival rate after initial recurrence was 36%. In patients with soft tissue or nodal recurrence, the 5-year survival rates were 49% and 38%, respectively; six (11%) of 53 patients whose initial recurrence was in a visceral organ achieved prolonged remission. Primary lesion anatomic site, thickness, pathologic type, and interval from initial therapy to recurrence were unrelated to survival. Significant prognostic factors included the site of initial metastasis, stage of primary disease, and the successful complete eradication of gross disease by surgical excision or intensive chemotherapy.

Molecular analysis of nuc-1+, a gene controlling phosphorus acquisition in Neurospora crassa

In response to phosphorus starvation, Neurospora crassa makes several enzymes that are undetectable or barely detectable in phosphate-sufficient cultures. The nuc-1+ gene, whose product regulates the synthesis of these enzymes, was cloned and sequenced. The nuc-1+ gene encodes a protein of 824 amino acids with a predicted molecular weight of 87,429. The amino acid sequence shows homology with two yeast proteins whose functions are analogous to that of the NUC-1 protein. Two nuc-1+ transcripts of 3.2 and 3.0 kilobases were detected; they were present in similar amounts during growth at low or high phosphate concentrations. The nuc-2+ gene encodes a product normally required for NUC-1 function, and yet a nuc-2 mutation can be complemented by overexpression of the nuc-1+ gene. This implies physical interactions between NUC-1 protein and the negative regulatory factor(s) PREG and/or PGOV. Analysis of nuc-2 and nuc-1; nuc-2 strains transformed by the nuc-1+ gene suggests that phosphate directly affects the level or activity of the negative regulatory factor(s) controlling phosphorus acquisition.