Phase I chemoprevention study of difluoromethylornithine in subjects with organ transplants

Individuals who receive life-saving organ transplants and the required immunosuppression often develop secondary cancers. One of the most common secondary cancers is nonmelanoma skin cancer in sun-exposed areas. Attempts to prevent these cancers have not been successful. Difluoromethylornithine (DFMO), a suicide inhibitor of ornithine decarboxylase (ODC), is a known experimental cancer prevention agent that is being evaluated in a number of human cancer prevention trials. This report describes a Phase I trial in 18 organ transplant recipients, randomized to 1.0 and 0.5 g of DFMO or a placebo, designed to look at short-term toxicities over 28 days as well as the impact of DFMO on two biological parameters, skin polyamines and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ODC activity. Blood levels of DFMO were also measured. The results indicate that DFMO was well tolerated over the 28-day period. The TPA-induced ODC activity in 3-mm skin biopsies was significantly lowered by 80 and 67% at the two dose levels. Polyamine levels were not affected significantly except for putrescine at the 0.5-g level. Blood levels of DFMO were about two times higher than expected, based on our prior pharmacokinetic studies. Our studies indicate that DFMO is a reasonable agent that should be tested further in larger Phase 2b trials in this population as a chemopreventive agent. TPA-induced ODC activity appears to be a relevant intermediate biological assay.

Peptoids as endothelin receptor antagonists

A series of new peptoids as endothelin receptor antagonists has been synthesized. Screening them for their ability to bind with endothelin receptors (ET(A) and ET(B)) competitively in the presence of (125I) endothelin led to the discovery of compounds as possible leads with IC50s in the low micromolar concentrations.

A novel transformation suppressor, Pdcd4, inhibits AP-1 transactivation but not NF-kappaB or ODC transactivation

Pdcd4 is a novel transformation suppressor that is highly expressed in promotion-resistant (P-) mouse epidermal JB6 cells but not in susceptible (P+) cells. Overexpression of pdcd4 cDNA in stably transfected P+ cells rendered cells resistant to tumor promoter-induced transformation, indicating that elevated expression of Pdcd4 protein is sufficient to suppress neoplastic transformation. To determine whether Pdcd4 suppresses neoplastic transformation through inhibiting known transformation required events, we examined the possibility that pdcd4 inhibited the activation of AP-1 or NF-kappaB dependent transcription or of ornithine decarboxylase (ODC) activity. Activation of AP-1-dependent transcriptional activity was inhibited by pdcd4 expression in a concentration dependent manner. In contrast, Pdcd4 slightly increased NF-kappaB-dependent transcription and did not alter ODC enzymatic activity. Previous studies suggested that activation of AP-1 was required for P+ cell transformation as well as for tumor promotion in vivo. These results indicate that Pdcd4 functions as a transformation suppressor, possibly through inhibiting AP-1 activation in combination with other factors such as enhancing NF-kappaB activation. Pdcd4 may thus constitute a useful molecular target for cancer prevention.

Protein kinase C-epsilon transgenic mice: a unique model for metastatic squamous cell carcinoma

Squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) are the most common forms of human skin cancer. BCC is slow growing and mostly localized, whereas SCC metastasizes to the regional lymph nodes and subsequently to distal organs. In murine skin carcinogenesis models for SCC, the incidence of metastasis is very low. We report here that FVB/N transgenic mice, which overexpress (approximately 18-fold) epitope-tagged protein kinase C-epsilon (T7-PKCepsilon) protein in the epidermis provide a unique murine model system for highly malignant/metastatic SCC. Skin tumors were developed by the initiation-promotion protocol (initiation with 100 nmol 7,12-dimethyl-benz[a]anthracene; promotion with 5 nmol 12-O-tetradecanoylphorbol-13-acetate twice weekly). T7-PKCepsilon transgenic mice showed 92% suppression of papilloma development compared with wild-type littermates after 23 weeks of tumor promotion. However, within 15-20 weeks of 12-O-tetradecanoylphorbol-13-acetate promotion, 40% of T7-PKCepsilon mice developed at least one carcinoma compared with 7% of the wild-type mice. All carcinomas from T7-PKCepsilon mice appeared without prior papilloma formation. Interestingly, 7,12-dimethyl-benz[a]anthracene alone resulted in the development of squamous cell carcinomas in 22% of T7-PKCepsilon mice, whereas wild-type littermates developed no tumors. Histopathological analysis of tumors from multiple T7-PKCepsilon mice revealed moderately differentiated SCC invading the dermal region with neoplasia appearing to originate and invade from the hair follicle. Carcinomas of T7-PKCepsilon mice rapidly metastasized to regional lymph nodes within 3 weeks of appearance. In wild-type mice, the grade of the invading tumors, originating from interfollicular epidermis, was pathologically categorized as well-differentiated SCC and remained localized to the dermis. The T7-PKCepsilon transgenic mice may provide a rapid and unique in vivo model to investigate metastatic SCC.

Retinoic acid (RA) receptor transcriptional activation correlates with inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced ornithine decarboxylase (ODC) activity by retinoids: a potential role for trans-RA-induced ZBP-89 in ODC inhibition

Evaluation of retinoic acid receptor (RAR) subtype-selective alpha and gamma agonists and antagonists and a retinoid X receptor (RXR) class-selective agonist for efficacy at inhibiting both induction of ornithine decarboxylase (ODC) by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis and rat tracheal epithelial cells and the appearance of papillomas in mouse epidermis treated in the 2-stage tumor initiation-promotion model indicated that (i) RXR class-selective transcriptional agonists, such as MM11246, were not involved in ODC inhibition; (ii) RAR-selective agonists that induce gene transcription from RA-responsive elements (RAREs) were active at low concentrations; (iii) RAR-selective antagonists that bind RARs and inhibit AP-1 activation on the collagenase promoter but do not activate RAREs to induce gene transcription were less effective inhibitors; and (iv) RARgamma-selective retinoid agonists were more effective inhibitors of TPA-induced ODC activity than RARalpha-selective agonists. These results suggest that RARE activation has a more important role in inhibition of ODC activity than RXR activation or AP-1 inhibition and that RARgamma-selective agonists would be the most useful inhibitors of epithelial cell proliferation induced by tumor promoters. The natural retinoid all-trans-RA induced expression of transcription factor ZBP-89, which represses activation of the GC box in the ODC promoter by the transcription factor Sp1.

Anthocyanin, bisabolol and phenylammonialyase activity in cell cultures of Populus deltoides

Phenolics, anthocyanin and alpha-bisabolol production from poplar (Populus delotides) in tissue culture was determined. A number of phenolic acids were identified by HPLC. PAL activity in response to phytohormones, cells growth and anthocyanin production showed a positive correlation. A component, alpha-bisabolol, was identified using gas chromatography and UV spectroscopy. In vitro production of said metabolites was influenced by phytohormones.

Plasma membrane Ca(2+) pump isoform 3f is weakly stimulated by calmodulin

Isoform 3f of the plasma membrane Ca(2+) pump is a major isoform of this pump in rat skeletal muscle. It has an unusual structure, with a short carboxyl-terminal regulatory region of only 33 residues when compared with the 77 to 124 residues found in the other isoforms. Also, whereas the regulatory regions of the other isoforms, downstream of the alternative splice, consist of two homologous groups, the sequence of 3f is not related to either group. A synthetic peptide representing the calmodulin binding domain of isoform 3f had a much lower calmodulin affinity (with a K(d) of 15 nM) than the corresponding peptide of isoform 2b (K(d) value was 0.2 nM). The characteristics of this domain were further studied by making chimeras of the 3f regulatory region with the catalytic core of isoform 4 and by making the full-length isoform 3f. Both constructs bound to calmodulin-Sepharose. The chimera was fully active without calmodulin, showing no stimulation of activity when calmodulin was added. The full-length isoform 3f was slightly activated by calmodulin. These data show that the regulatory region of isoform 3f is only a weak autoinhibitor of the enzyme, in contrast to the properties of all the other isoforms studied so far. Rather, this isoform is a special-purpose, constitutively active form of the enzyme, expressed primarily in skeletal muscle and as a minor isoform in brain.

Transgenic mice overexpressing protein kinase C epsilon in their epidermis exhibit reduced papilloma burden but enhanced carcinoma formation after tumor promotion

To determine the role that protein kinase C epsilon (PKCepsilon) may play in skin growth, differentiation, and tumor promotion, transgenic mice were generated that overexpressed an epitope-tagged protein kinase C epsilon (T7-PKCepsilon) in their epidermis using the human keratin 14 promoter. Three independent mouse lines that overexpressed the T7-PKCepsilon in their epidermis were produced. The three independent lines 206, 224, and 215 exhibited a 3-, 6-, and 18-fold elevation, respectively, in the level of PKCepsilon immunoreactive protein. Line 215 exhibited a 19-fold greater phosphatidylserine and 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulated kinase activity than line 224. Line 206 exhibited a low basal T7-PKCepsilon activity, which failed to be stimulated by phosphatidylserine and TPA. All of the line 215 transgenic mice (F0 to the F2 generation) displayed phenotypic changes in the skin. The phenotypic changes progressed gradually, starting around 4-5 months of age, with mild dryness of the tail accompanied by hair loss and inflammation at the base of the tail. Hyperproliferation and ulceration of the affected regions were observed around 7-8 months of age. The hyperproliferative epidermis from the affected regions exhibited an expansion of the suprabasal epidermal cells. Inflammation and/or ulceration were also observed in the dorsal skin, the ears, and around the eyes. The line 215 mice, which expressed the highest level of PKCepsilon, were evaluated for sensitivity to mouse skin tumor promotion by TPA. Tumors were elicited by the initiation (7,12-dimethylbenz[a]anthracene, 100 nmol)-promotion (TPA, 5 nmol/twice weekly) protocol. The papilloma burden was reduced by 95-96% for male and female T7-PKCepsilon mice compared to wild-type controls. However, carcinomas developed rapidly in the T7-PKCepsilon mice treated with 7, 12-dimethylbenz[a]anthracene and TPA. These carcinomas appeared to form independently of prior papilloma development. These results demonstrate that PKCepsilon is an important regulator of skin tumor development.

Effects of Fasciola gigantica infection on growth and nutrient utilisation of buffalo calves

The effects of Fasciola gigantica infection on bodyweight gain, dry matter intake, digestibility of nutrients and feed conversion efficiency in buffalo calves were investigated. Nine male buffalo calves of the Murrah breed, aged 12 to 15 months with a mean (se) bodyweight of 166 (12.5) kg, were randomly assigned to groups of five (group 1) and four (group 2). The animals in group 1 were given 1000 viable, mature metacercariae of F gigantica orally, while the animals in group 2 served as uninfected controls. They were stall fed on diets containing a concentrate mixture and ad libitum wheat straw and were maintained by standard management practices for a period of 165 days after infection. The average daily liveweight gain of the infected animals was 110.6 g, compared with 439.4 g in the uninfected controls, and was associated with the appearance and establishment of immature flukes in hepatic bile ducts. The feed conversion efficiency declined significantly (P<0.01) from 41 days after infection and was lowest at the end of the experiment. F gigantica infection did not influence the digestibility of the nutrients. The impaired feed conversion efficiency was mainly due to a reduction in dry matter intake due to inappetence.

The rate of activation by calmodulin of isoform 4 of the plasma membrane Ca(2+) pump is slow and is changed by alternative splicing

A reconstitution system allowed us to measure the ATPase activity of specific isoforms of the plasma membrane Ca(2+) pump continuously, and to measure the effects of adding or removing calmodulin. The rate of activation by calmodulin of isoform 4b was found to be very slow, with a half-time (at 235 nM calmodulin and 0.5 microM free Ca(2+)) of about 1 min. The rate of inactivation of isoform 4b when calmodulin was removed was even slower, with a half-time of about 20 min. Isoform 4a has a lower apparent affinity for calmodulin than 4b, but its activation rate was surprisingly faster (half time about 20 s). This was coupled with a much faster inactivation rate, consistent with its low affinity. A truncated mutant of isoform 4b also had a more rapid activation rate, indicating that the downstream inhibitory region of full-length 4b contributed to its slow activation. The results indicate that the slow activation is due to occlusion of the calmodulin-binding domain of 4b, caused by its strong interaction with the catalytic core. Since the activation of 4b occurs on a time scale comparable to that of many Ca(2+) spikes, this phenomenon is important to the function of the pump in living cells. The slow response of 4b indicates that this isoform may be the appropriate one for cells which respond slowly to Ca(2+) signals.

Transgenic mice overexpressing protein kinase Cdelta in the epidermis are resistant to skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate

To determine the role of protein kinase Cdelta in mouse skin carcinogenesis, we have developed transgenic FVB/N mouse lines expressing in the epidermis an epitope-tagged protein kinase Cdelta (T7-PKCdelta) regulated by the human keratin 14 promoter. The untreated T7-PKCdelta mice displayed excessive dryness in the skin of the tail with a variable penetrance over time. Histologically, the tail skin showed hyperplasia with evidence of hyperkeratosis. The epidermis of the rest of the T7-PKCdelta mouse was unremarkable. Despite this mild phenotype, the effects of PKCdelta overexpression on mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) were dramatic. Two independent lines of T7-PKCdelta mice (16 and 37) expressing the T7-PKCdelta transgene were examined for responsiveness to skin tumor promotion by 7,12-dimethylbenz[a]anthracene and TPA. By immunoblot analysis, the T7-PKCdelta-16 and T7-PKCdelta-37 mice showed an 8- and 2-fold increase of PKCdelta protein. The T7-PKCdelta-16 mice averaged 300% more T7-PKCdelta activity than the T7-PKCdelta-37 mice did. The T7-PKCdelta-37 mice did not manifest any difference in tumor burden or incidence. However, the reduction in papilloma burden at 25 weeks of promotion for the T7-PKCdelta-16 mice relative to wild-type mice averaged 72 and 74% for males and females, respectively. The T7-PKCdelta-16 mice reached 50% papilloma incidence between 12 and 13 weeks of promotion compared with 8 weeks for wild-type mice. Furthermore, the carcinoma incidence was also reduced in T7-PKCdelta-16 mice. Carcinoma incidence at 25 weeks of promotion treatment was: wild-type females, 78%; T7-PKCdelta16 females, 37%; wild-type males, 45%; and T7- PKCdelta-16 males, 7%. Thus, PKCdelta when expressed at sufficient levels can suppress skin tumor promotion by TPA.

Tumor promoter-induced ornithine decarboxylase gene expression occurs independently of AP-1 activation

Activator protein 1 (AP-1) transactivation and ornithine decarboxylase (ODC) activity have been established as essential downstream effectors of mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA). Previous studies have shown that inhibition of either AP-1 transactivation or ODC activity suppressed tumor promoter-induced transformation. By utilizing the JB6 mouse epidermal cell system, the present study determined whether TPA-induced ODC gene expression and activity is independent of AP-1 transactivation. In three independent JB6 (P+) clones, stably expressing dominant negative c-jun, TPA-induced ODC gene expression and activity were similar compared to JB6 P+ cells expressing vector-control alone, while AP-1-dependent transcription was inhibited. Transformation-insensitive JB6 (P-) cells, which lack TPA-inducible c-jun expression, also exhibited similar induction of ODC activity by TPA. alpha-Difluoromethylornithine, an irreversible inhibitor of ODC, attenuated, at an equivalent IC50, both TPA-induced ODC activity and anchorage-independent growth of JB6 P+ cells, despite no inhibition of AP-1 transactivation. Taken together, the results presented indicate that TPA-induced ODC gene expression and activity are independent of AP-1 transactivation. Because inhibition of either AP-1 or ODC precludes TPA-induced transformation, and because ODC is independent of AP-1, we propose that there are at least two pathways to transformation. Each pathway is required but not sufficient for transformation.

Ras mutation, irrespective of cell type and p53 status, determines a cell's destiny to undergo apoptosis by okadaic acid, an inhibitor of protein phosphatase 1 and 2A

Okadaic acid (OA), a toxin from the black sponge Halicondria okadai, is a specific inhibitor of serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A). OA is a tumor promoter but also induces apoptosis in some tumor cell lines. In this study, we determined whether ras mutation and/or p53 status are characteristics associated with the cell's sensitivity to the induction of apoptosis by OA. Several cell lines that differed in ras and p53 mutations were treated with OA (10-100 nM). At 24 to 48 h after treatment, the percentage of cells undergoing apoptosis was quantitated. The cell lines with mutations in either H-ras (human bladder carcinoma cell line T24 and mouse keratinocyte cell line 308), or K-ras (human colon carcinoma cell lines DLD-1 and HCT116; human prostate cancer cell lines LNCaP and PC-3; human lung cancer cell lines Calu-6 and SKLU-1; and human pancreatic cancer cell line MIAPaCa2) were more sensitive to OA-induced apoptosis (3- to 10-fold) than the cell lines that lacked the ras mutation (mouse epidermal cell lines C50 and JB6; murine fibroblast cell line NIH3T3; human colon cancer cell line HT29; human kidney epithelial cell line Hs715.K; and human pancreatic cancer cell line Bx-PC3). Similarly, using isogenic cell lines we found that overexpression of mutated H-ras in NIH3T3 and in SV40 immortalized human uroepithelial cells (SVHUC) enhanced their sensitivity to undergo apoptosis in response to OA treatment. The T24, DLD-1, SKLU-1, Calu-6, and MIAPaCa2 cell lines express mutated p53. The SVHUC as well as their ras-transfected counterparts have inactive p53 due to complex formation between large "T" antigen and p53. Taken together, these results imply that OA-induced apoptosis may involve a p53-independent pathway. The transfectants (NIH3T3-ras and SVHUC-ras), which express mutated H-ras, have up-regulated PP2A activity. OA treatment inhibited in vivo the levels of PP1 and PP2A activity, and induced apoptosis in SVHUC-ras and other cell lines. We conclude that OA-induced cell death pathway in ras-activated cell lines may involve a cross talk between PP1 and PP2A and ras signaling pathways. In light of the present results, the current theory that OA promotes mouse skin tumor formation by selective expansion of initiated cells that harbor ras mutations needs reevaluation.

Primary experimental infection of riverine buffaloes with Fasciola gigantica

The clinical course of the primary experimental Fasciola gigantica infection was investigated in riverine buffalo calves of the Murrah breed. Nine male calves aged 12-15 months were randomly assigned to two groups of five (Group I) and four (Group II) animals. Each animal in Group I, was orally infected with 1000 metacercariae (mc) of F. gigantica, whereas Group II animals did not receive any infection dose and served as uninfected controls. No clinical signs of fasciolosis were observed until the sixth week post-infection (PI). Group I animals, however, developed recognised symptoms of acute fasciolosis, comprising apyrexic inappetance, anemia, poor weight gain, diarrhoea and sub-mandibular and facial oedema, respectively, from 5, 6, 8, 16 and 17 weeks PI. The signs were intermittent in nature and of variable duration. The prepatent period was of 92-97 days (mean 95.2 +/- 3.1). One of the five infected animals died on Day 147 PI. At necropsy, 36.8 +/- 11.0% of the infection dose was recovered as adult fluke population. The gross lesions were primarily biliary in nature. Group II, the uninfected controls, throughout the study period of 165 days PI, did not show any symptom and were negative for F. gigantica. The study demonstrated that the onset of adverse effects of F. gigantica on the growth and health of the infected host was mainly noted during late prepatency much before coprological prediction and diagnosis. The significance of preventive therapy against fasciolosis during prepatency has been stressed in endemic areas.

Protein kinase C phosphorylates plasma membrane Ca2+ pump isoform 4a at its calmodulin binding domain

Phosphorylation by protein kinase C of isoform 4a of the human plasma membrane Ca2+ pump (hPMCA4a) was studied using the COS cell expression system. Phosphorylation of several truncated mutants of hPMCA4a indicated that a single phosphorylation site lies in a region between residues 1113 and 1125. This region is within the calmodulin binding domain and contains a single phosphorylatable residue, serine 1115. Converting this serine to an alanine diminished phosphorylation greatly. Phosphorylation, done in the absence of calmodulin, did not affect subsequent calmodulin binding, but previous binding of calmodulin did inhibit phosphorylation. Moreover, no significant shift in the calmodulin response curve of hPMCA4a was observed when phosphorylation was mimicked by converting serine 1115 to an acidic residue. The calmodulin binding domain of hPMCA4a is much longer than other calmodulin binding domains and has been suggested to consist of two binding lobes interrupted by a short nonbinding region. The findings of this study indicate that serine 1115 is the residue phosphorylated by protein kinase C, and that it lies within the nonbinding region of the calmodulin binding domain.

A randomized, placebo-controlled trial of low-dose alpha-difluoromethylornithine in individuals at risk for colorectal cancer

DFMO is an irreversible inhibitor of ornithine decarboxylase (ODC), the key enzyme in mammalian polyamine biosynthesis. The goal of this study was to determine the effects of DFMO 0.5 g/m2/day as a single oral dose on polyamine and ODC levels in rectal, rectosigmoidal, and cecal colonic mucosae of individuals at risk for colon cancer because of a personal history of adenomatous polyps of the colon or a family history of colon cancer in at least one first-degree relative. A second goal was to determine toxicity of this treatment given over 1 year. Forty-five randomized subjects had a flexible sigmoidoscopy with no preparation and a colonoscopy after lavage preparation at baseline, a sigmoidoscopy with no preparation after 3 months, and both procedures (as at baseline) after 12 months, with mucosal biopsies taken from the rectosigmoid area (sigmoidoscopy) or rectal and cecal areas (colonoscopy) for evaluations of ODC and polyamine levels. Significantly decreased levels of putrescine and spermidine were found in rectosigmoid colonic mucosae of DFMO-treated (n = 24) compared with placebo (n = 21) subjects at 3 months (P = 0.03 and 0.04) and 12 months (P = 0.005, P = 0.004). Similar trends, none reaching statistical significance, were found for individual polyamine levels in rectal and cecal mucosae. No significant differences in ODC levels were detected marginally. There was evidence of global suppression of ODC and polyamine levels in the treatment group (P = 0.035). Three DFMO recipients (12.5%) developed clinically noticeable and audiologically demonstrated hearing loss, which was reversible and attributed to DFMO after 3 months (two subjects) and 12 months (one subject). The tissue polyamine changes demonstrated in this study are consistent with findings in other studies in colon and other tissues. The ototoxicity findings here suggest that investigation of other DFMO schedules, such as ones with a drug "holiday," will be a necessary step before Phase III chemoprevention studies can be pursued.

Correlation of fine needle aspiration biopsy and fluoride-18 fluorodeoxyglucose positron emission tomography in the assessment of locally recurrent and metastatic head and neck neoplasia

OBJECTIVE

Patients with primary head and neck neoplasia can present during follow-up with suspected recurrence, and both fine needle aspiration biopsy (FNAB) and fluoride-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scan are available methodologies for evaluating these patients. Our objective was to retrospectively correlate patients who underwent both FNAB and FDG-PET scan in order to assess the possibility of recurrent neoplasia.

STUDY DESIGN

The cytopathology files at Saint Louis University Health Sciences Center were retrospectively searched for patients with known primary head and neck malignancies beginning in 1995. Suspected recurrence and local metastases evaluated by both FNAB and FDG-PET scan were correlated.

RESULTS

Twenty-eight patients received a combined total of 37 FNABs with concurrent FDG-PET scans. The majority of patients had primary oropharyngeal squamous cell carcinoma with intermixed, single cases of other primary head and neck neoplasms. Thirty of the 32 aspirates with recurrent or locally metastatic disease had combined positive findings by both FNAB and FDG-PET scan, yielding a sensitivity of 94%. One nonspecific and one negative FDG-PET scan came from a patient who had disease confirmed by FNAB. Five patients had negative findings by both methods that were supported by the subsequent clinical course.

CONCLUSION

FNAB can provide confirmatory evidence of disease in a clinically suspicious abnormality with nonspecific FDG-PET results. FNAB and FDG-PET are highly sensitive for tumors in cases of clinically suspected recurrence and locally metastatic disease.

Phase I chemoprevention study of piroxicam and alpha-difluoromethylornithine

A two-step Phase I study of piroxicam (PXM) and a-difluoromethylornithine (DFMO) alone and in combination was initiated to assess toxicity and the impact of these drugs on several biological markers. In step 1, 12 subjects with a history of skin cancers were assigned to receive PXM 10 mg every day (q.d.) or 10 mg every other day (q.o.d.). The dosage of PXM 10 mg q.o.d. was tolerated. No changes were seen in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) or urinary polyamine levels. Steady-state serum levels of PXM were consistent with the oral dose level. In step 2, 31 subjects with stage 0 or I nonmelanoma skin cancers, stage A or B prostate or colon cancer, or stage I breast cancer or who had a family history of cancer were randomized to receive DFMO 0.5 g/m2, PXM 10 mg q.o.d., or the combination of DFMO and PXM. In addition to the biological markers of TPA-induced ODC activity in skin biopsies and urinary polyamine levels, we measured urinary 11-dehydrothromboxane B2, a specific metabolite of thromboxane A2. Of the 12 subjects on DFMO/PXM, 2 dropped out for non-drug-related reasons. Three developed grade-2 drug-related toxicities. One subject developed dyspnea that resolved and was able to continue on the study for 6 months. One subject who developed diarrhea that resolved after 5 days was also able to restart the drug without a recurrence. A third subject described intermittent episodes of tinnitus starting 4 h after taking PXM that lasted only 5 s and did not progress on treatment. Comparing the 6-month measurements with pretreatment, DFMO/PXM or DFMO significantly reduced TPA-induced ODC levels (Ps, 0.03 and 0.05). Urinary polyamine levels of spermidine decreased slightly with the DFMO/PXM or DFMO alone, whereas putrescine decreased with PXM alone. Levels of 11-dehydrothromboxane B2 were depressed by PXM and PXM/DFMO. The doses of DFMO/PXM determined in step 2 are potential starting dosages for Phase IIa and IIb chemoprevention trials.

Prevalence of seizures and paralysis in a rural community

A cross-sectional study covering four adjoining villages in Haryana during 1993 was carried out among 8595 subjects to find out cases having seizures or paralysis. The prevalence of seizures (n = 69) was found to be 8.03 per 1000 population. Out of 69 seizures, 48(69%) were true seizures and 21(31%) were febrile seizures. The prevalence of seizures was highest (14.05 per 1000) in the age group of > 1-4 years. Of 40 males with seizures, 22(55%) had epileptic seizures and 18(45%) had febrile seizures. Of the 29 females, 26(89%) had epileptic seizures and 3(11%) had febrile seizures. There were 25 cases of pseudoseizures. The prevalence of paralysis (n = 60) was 6.98 per 1000. Of these, 38 cases (63%) were due to poliomyelitis which is the highest so far the paralysis is concerned. Of 60 cases, 34 occurred among males and 26 among females. The prevalence of paralysis was highest (12.42 per 1000) among 0-1 year age group. As the prevalence of seizures is sufficiently high in rural areas, the primary health care doctors should be trained in counselling and therapy of seizures. As regarding paralysis due to poliomyelitis the recent success of pulse polio immunisations is commendable and which in near future is expected to eradicate poliomyelitis.

Protein kinase C phosphorylates the "a" forms of plasma membrane Ca2+ pump isoforms 2 and 3 and prevents binding of calmodulin

Phosphorylation by protein kinase C of the "a" and "b" variants of plasma membrane Ca2+ pump isoforms 2 and 3 was studied. Full-length versions of these isoforms were assembled and expressed in COS cells. Whereas the "a" forms were phosphorylated easily with PKC, isoform 2b was phosphorylated only a little, and isoform 3b was not phosphorylated at all. Phosphorylation of isoforms 2a and 3a did not affect their basal activity, but prevented the stimulation of their activity by calmodulin and their binding to calmodulin-Sepharose. This indicated that phosphorylation prevented activation of these isoforms by preventing calmodulin binding. Based on these results, phosphorylation of the pump with PKC would be expected to increase free intracellular Ca2+ levels in those cells where isoforms 2a and 3a are expressed.

Comparative evaluation of breast lesions with the help of impression smears, histopathology and mammography

A total of 148 surgically removed benign and malignant breast lesions were studied to correlate cytomorphologial features in impression smears and histopathological sections. Mammograms were taken prior to surgery. Role of mammography in detection of non-palpable breast lesions was enlightened. Impression smears helped in quick diagnosis (intraoperative) and overall accuracy obtained was 97.4%. Cluster predominant and Grade II nuclear grading on smear pattern was seen in 58.8% and 57.4% cases respectively amongst the 68 malignant cases. 45% cases revealed non-palpable breast lesions on mammography which was later confirmed on histopathology.

Secondary syphilis in HIV infection - a diagnostic dilemma

A case of secondary syphilis in HIV infection is being reported. The patient presented with skin rash only. VDRL was found to be negative and HIV testing was positive. He was treated for secondary syphilis with clinical response. Blood VDRL test was subsequently reported as reactive.

Improvement of limb circulation in peripheral vascular disease using epidural spinal cord stimulation: a prospective study

Spinal cord stimulation was used in 46 patients for pain associated with lower extremity ischemic vascular disease that was considered to be nonreconstructable. Thirty-nine patients who had a follow-up examination between 2 and 36 months after the procedure form the basis of this report. Thirty (77%) of 39 cases were considered successful. Clinical endpoints indicating failure included amputation, vascular reconstruction, poor pain relief, or hardware malfunction. The transcutaneous partial pressure of oxygen (TcPO2) increased in both target and control feet. In patients with good outcome with a preimplantation TcPO2 of less than 30 mm Hg, TcPO2 increased significantly (p < 0.05). Pulse volume recording improved significantly (p < 0.05) at the thigh, metatarsal, and great toe levels in successfully treated patients. Peak blood flow velocity also showed a significant increase in patients with good outcome (p < 0.05). Patients with a TcPO2 of less than 10 mm Hg following stimulation tended to undergo amputation within the first 3 months. Improvement in pain control, combined with an increase in TcPO2 values that was greater than 10 mm Hg, were significant early predictors of long-term success. An initial increase in peak blood flow velocities (measured in Doppler studies) of greater than 10 mm also signified a good long-term outcome. Spinal cord stimulation appears to be a useful therapeutic modality for controlling pain and improving perfusion in a select group of patients with end-stage ischemic vascular disease considered nonreconstructable. The best results were seen in patients with severe claudication and rest pain without trophic changes in the foot. The mechanism of this beneficial effect is not yet completely understood.

Replacement of Val674 by Pro increases the sensitivity of the plasma membrane Ca2+ pump to inhibition by Mg2+

A cDNA encoding a plasma membrane Ca2+ pump mutant V674P(ct120) was constructed and expressed in COS-1 cells. Immunoblots of transfected COS-1 membranes showed that the V674P(ct120) and the wild-type hPMCA4b(ct120) proteins were expressed at similar levels. The change of Val674 to Pro reduced the activity of the hPMCA4b(ct120) to an extent similar to that observed previously in the full-length Ca2+ pump (Adamo et al. (1995) J. Biol. Chem. 270, 30111-30114). Despite its lower activity, the apparent affinity for Ca2+ of the V674P(ct120) enzyme was at least as high as that of hPMCA4b(ct120), indicating that substitution of Val674 by Pro did not impair the interaction of the enzyme with Ca2+. The sensitivity of the V674P(ct120) enzyme to inhibition by vanadate was not significantly different from that of the hPMCA4b(ct120), supporting the idea that the mutation did not alter the equilibrium between E2-E1. The study of the Mg2+ dependency of the Ca2+ transport showed that the V674P(ct120) mutant reached maximum activation at 100 microM Mg2+ in contrast with 500 microM in the hPMCA4b(ct120). Furthermore, while at 2 mM Mg2+ the hPMCA4b(ct120) showed no sign of inhibition, the activity of the mutant decreased to less than 50% of the maximum activity observed at 100 microM Mg2+. These results indicate that the decrease in the activity observed upon substitution of Val674 by Pro was due to a higher sensitivity to Mg2+ as inhibitor.

Protein kinase C activates the plasma membrane Ca2+ pump isoform 4b by phosphorylation of an inhibitory region downstream of the calmodulin-binding domain

The carboxyl-terminal region of the plasma membrane Ca2+ pump isoform 4b contains two autoinhibitory regions which keep the pump inactive in the absence of activators such as calmodulin. One of these regions is approximately coterminous with the calmodulin-binding domain, while the second region is downstream (Verma, A. K., Enyedi, A., Filoteo, A. G., and Penniston, J. T. (1994) J. Biol. Chem. 269, 1687-1691). The carboxyl-terminal region has also been identified as the site for phosphorylation of this isoform by protein kinase C (Wang, K. K. W., Wright, L. C., Machan, C. L., Allen, B. G., Conigrave, A. D., and Roufogalis, B. D. (1991) J. Biol. Chem. 266, 9078-9085). Using constructs lacking various numbers of residues at the carboxyl terminus, we studied the degree of phosphorylation by protein kinase C and the resultant activation of Ca2+ transport. The results showed that the most specific and easy phosphorylation occurred in a region of about 20 residues which is downstream of the calmodulin-binding domain, and that the downstream inhibitory domain had also about the same size and location. Phosphorylation partially activated the pump by removing only the inhibition due to this region. Binding of calmodulin to the calmodulin-binding domain activated the pump more fully by removing the inhibition due to both regions, regardless of the state of phosphorylation at the downstream inhibitory region.

Localization of the 12-O-tetradecanoylphorbol-13-acetate response of the human ornithine decarboxylase promoter to the TATA box

In a previous study, we narrowed the region of the human ornithine decarboxylase (ODC) promoter responsive to 12-O-tetradecanoylphorbol-13-acetate (TPA) to nt -42 to +54 around the transcription initiation site (Kim YJ, Pan H, Verma AK, Mol Carcinog 10:169-179, 1994). Here we report defining the role of the TATA box in TPA-induced transcription from the -42/+54 ODC promoter fragment. A transversion mutation at the third position of the TATA box (TATAAGT-->TAAAAGT) reduced TPA responsiveness of the reporter construct -42/+54 ODC-Luc by 49%. Electrophoretic mobility shift assays (EMSAs) using HeLa cell nuclear protein extracts revealed no differences in the binding pattern between the natural -42/+54 ODC promoter element and the -42/+54 ODC promoter element containing the T-->A mutation. However, antibodies to the general transcription factor TFIIB disrupted the DNA-protein complexes normally formed with the -42/+54 ODC promoter element in EMSAs. A consensus TATA box oligonucleotide formed two bands, with the faster mobility band displaying enhanced binding with nuclear protein extracts from TPA treated cells. Furthermore, incubation of HeLa cell nuclear extracts with an oligonucleotide containing the ODC TATA box also caused formation of two specific bands in EMSA. Both bands exhibited augmented binding to nuclear proteins from TPA-treated cells. Introduction of the T-->A transversion mutation in the ODC TATA oligonucleotide eliminated binding of the faster migrating band formed with the natural ODC TATA oligonucleotide. These results indicate that TPA modulation of the general transcription machinery may play a role in the TPA-activated transcription of the human ODC promoter.

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced ornithine decarboxylase activity by genistein, a tyrosine kinase inhibitor

The effects of the protein tyrosine kinase inhibitor genistein on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity in monkey kidney epithelial CV-1 cells were determined. CV-1 cells were pretreated with genistein for 2 hr before treatment with 100 nM TPA. ODC activity was determined 9 hr after TPA treatment. Genistein inhibited TPA-induced ODC activity at 0.1, 1, 10, 25, 50, 100, 200, and 400 microM by 0%, 0%, 42%, 59%, 62%, 81%, 91%, and 100%, respectively (IC50 = 20 microM). Genistein inhibited TPA-induced mitogen-activated protein kinase (MAPK) tyrosine phosphorylation and the accumulation of steady state levels of ODC mRNA at 400 microM but not at 25 microM. Genistein, at 25 microM, did not alter the TPA-induced phosphorylation of p90 ribosomal S6 kinase but caused a approximately 50% decrease of the TPA-induced phosphorylation of p70 S6 kinase (p70S6K), a protein kinase involved in the control of translational efficiency. Taken together, these data indicate that genistein may inhibit TPA-induced ODC activity at the transcriptional and translational levels through the inhibition of MAPK and p70S6K activation, respectively. The regulation of MAPK and p70S6K may be mediated through different protein tyrosine kinases that have differential sensitivity to genistein.

Detection of isoform 4 of the plasma membrane calcium pump in human tissues by using isoform-specific monoclonal antibodies

The epitope location and specificity of monoclonal antibodies JA9, 5F10 and JA3, raised against the human plasma membrane Ca2+ pump (hPMCA), were analysed by using synthetic peptides of the corresponding epitopes as well as the complete isoforms, hPMCA4b, hPMCA4a and hPMCA1b, expressed in COS-1 cells. The experiments with the peptides showed that JA9 reacted specifically with a region containing residues 51-75 of hPMCA4 (a or b), but not with the same region of isoforms 1, 2 or 3. JA3 reacted with residues 1156-1180, a region unique to hPMCA4b. 5F10 reacted in the region of residues 719-738, which is highly conserved in all PMCA isoforms. Indeed, 5F10 recognized all three isoforms expressed in COS-1 cells. JA9, in contrast, reacted with both variants a and b of hPMCA4 but not with hPMCA1, and JA3 recognized exclusively hPMCA4b. We used these antibodies to discern the distribution of hPMCA4a and hPMCA4b in human brain, heart, kidney and lung. In Western blots of human brain samples, we could identify both hPMCA4a and hPMCA4b. Heart tissue also showed isoform 4b, and probably 4a. In contrast, kidney and lung showed primarily hPMCA4b. In brain, overlapping bands that did not correspond to either variant of hPMCA4 were detected, and in kidney a band migrating in the same position as hPMCA1b was observed. The distribution of the a and b forms of hPMCA4 at the protein level, as analysed by these antibodies, is consistent with the available data about the abundance of mRNAs for the hPMCA isoforms. The presence of hPMCA4b in all the samples supports the proposed role of this isoenzyme as a constitutive form of the pump.

Functional expression and characterization of the mouse epitope tag-protein kinase C isoforms, alpha, beta I, beta II, gamma, delta and epsilon

To simplify the detection of the exogenously produced protein kinase C (PKC) isoforms, we constructed the T7-Tag PKC alpha, betaI, betaII, gamma, delta and epsilon expression plasmids. T7-Tag sequences (AlaSerMetThrGlyGlyGlnGlnMetGlyArg) were inserted at the 5'-end of the translational initiation site. Transient transfection of T7-Tag PKC expression plasmids into CV-1 cells increased the levels of PKC protein, and PKC activity. T7-Tag-PKC epsilon, like native PKC epsilon, transactivated the transcription of a NF-kappa B reporter construct. These results indicate that the plasmids encoding T7-Tag PKC are functional and may be useful to define the role PKC isoforms play in cell proliferation, differentiation and tumor promotion.

Superinduction of mouse epidermal ornithine decarboxylase activity by repeated 12-o-tetradecanoylphorbol-13-acetate treatments

A correlation of the levels of epidermal protein kinase C (PKC) isozymes, steady state levels of ornithine decarboxylase (ODC) mRNA, and ODC antizyme with the induction of ornithine decarboxylase (ODC) activity by a second repeat 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment to mouse skin was determined. A single application of TPA to female CD-1 mouse skin leads to a dramatic induction of ODC activity (approximately 3 nmol CO2/60 min/mg protein) which peaks at about 5 h after treatment. However, a superinduction of ODC activity (approximately 13 CO2/60 min/mg protein) is observed upon the second TPA application at 48 or 72 h after the first TPA treatment. Prior application of a tumor initiating dose of 7,12-dimethylbenz[a]anthracine to mouse skin did not influence the degree of induction of ODC by a repeat TPA treatment. Western Blot analyses using antibodies specific to PKC alpha, beta, gamma, delta and epsilon indicate detectable levels of PKC alpha, beta, delta and epsilon in mouse epidermal extracts. A time course of the effects of a single topical application of 20 nmol of TPA to the mouse skin indicate that none of PKC isozymes (alpha, beta, gamma, delta and epsilon) were completely downregulated at times (72 h) when ODC was overinduced by TPA. TPA-induced steady state levels of ODC mRNA did not correlate with the degree of superinduction of ODC activity by TPA. The second TPA treatment, 72 h after the first TPA treatment, which leads to superinduction of ODC activity did not decrease the levels of the ODC-antizyme. The results indicate that superinduction of mouse epidermal ODC activity is regulated in part post-transcriptionally and may not be the result of either a loss of PKC isoform(s) or a decrease in the levels of ODC antizyme.

Plasma membrane calcium pump isoform 4a has a longer calmodulin-binding domain than 4b

Alternate splicing of human plasma membrane calcium pump isoform 4 (hPMCA4) transcripts causes the expression of two variants, hPMCA4a and hPMCA4b, which have different downstream regulatory regions. Of the two, hPMCA4a has a lower affinity for calmodulin and a lower effective affinity for Ca2+ (Enyedi, A., Verma, A. K., Heim, R., Adamo, H. P., Filoteo, A. G., Strehler, E. E., and Penniston, J. T. (1994) J. Biol. Chem. 269, 41-43). Additional consequences of the alternate splice were studied by analyzing the characteristics of constructs (expressed in COS-1 cells) containing different portions of the carboxyl terminus of hPMCA4a. Our results show striking differences in the structure of the calmodulin-binding and autoinhibitory domains of the two variants. The calmodulin-binding region of hPMCA4b is a region of about 28 residues, whereas that of hPMCA4a is about 49 residues long and is probably interrupted by a region not involved in the binding. The autoinhibitory region of hPMCA4b (a part of the downstream region that keeps the molecule inactive in the absence of Ca2+-calmodulin) is divided between the 28-residue calmodulin-binding region and a downstream region, whereas in hPMCA4a, all of it is contained within the 49-residue calmodulin-binding region.

Community perception of mosquitos and mosquito control in some areas of urban Delhi and rural Alwar, Rajasthan

There is little information regarding community perception of mosquitos and and their control in India. A qualitative study based on In depth discussions with the people in Urban Delhi, and rural Alwar was carried out in August-September, 1995. In the Ghazipur and Munirka areas of Delhi, 63 respondent groups with 171 head counts, and 59 respondent groups and 305 persons in Alwar were met. Community responses to uniform set of questions on mosquito types, seasonality, biting, breeding places, ongoing control activities, and methods of personal protection were recorded. Most people in the areas surveyed viewed mosquitos primarily as a biting nuisance, and secondarily as agents of disease and debilitators of health. In general the knowledge regarding mosquitos was deficient. An overwhelming tendency to attribute mosquitogenic conditions to the unsavoury features of one's physical environment was observed in both areas. The methods of personal protection and attitudes to organised control are discussed.

Two residues that may ligate Ca2+ in transmembrane domain six of the plasma membrane Ca(2+)-ATPase

In order to identify Ca2+ ligands in the putative transmembrane domain 6 of the plasma membrane Ca2+ pump, amino acids Asn879, Met882, Asp883, and Ser887 were singly altered. Asn879, Met882, and Asp883 were chosen because the corresponding amino acids have been proposed as Ca2+ ligands in the sarcoplasmic reticulum Ca2+ pump (Clarke, D. M., Loo, T. W., and MacLennan, D. H. (1990) J. Biol. Chem. 265, 6262-6267). For the alterations, a fully active truncated version of the pump was used, because the interaction of Ca2+ with the pump could be studied without interference from calmodulin binding. The mutants at Asn and Asp did not carry out ATP-supported Ca2+ uptake and formed no acylphosphate from [gamma-32P]ATP, suggesting that, like the corresponding amino acids in the sarcoplasmic reticulum Ca2+ pump, these two are Ca2+ ligands. However, all the mutants at the position of Met882 showed some activity. Indeed, the Met882--> Ile mutant was fully active at a saturating Ca2+ concentration and only the K1/2 for Ca2+ activation was shifted slightly upward. Converting the Met to Thr (which is the corresponding residue in the sarcoplasmic reticulum Ca2+ pump) reduced the activity to 20% of the wild type, further emphasizing the differences between the two Ca2+ pumps. The mutant Ser887--> Ala was expressed in greater amounts than, and had a specific activity about 50% higher than, the wild type, indicating that this serine also could not be a Ca2+ ligand and could not replace the missing Thr at position Met882.

Epidemiology of chronic suppurative otitis media and deafness in a rural area and developing an intervention strategy

Of 613 children evaluated in a village in Haryana 94 (15.3%) were observed to have chronic suppurative otitis media (CSOM). Fifty eight (61.7%) children had hearing impairment. CSOM contributed to 71.6% of the hearing impaired (58/81). On analysis of association of CSOM with literacy and socio-economic status of mothers, and age, sex, and upper respiratory tract infections (URI) in children positive correlation was observed only with URIs (P < 0.001). Literacy and socio-economic status of the mothers did not correlate significantly with knowledge about treatment seeking, and ear cleaning practices, probably due to the narrow range of incomes and literacy levels. An intervention program consisting of play, demonstrations, health charts and slogans, and aural cleaning and antibiotic drops was introduced.

Lack of 12-O-tetradecanoylphorbol-13-acetate responsiveness of ornithine decarboxylase introns which have AP-1 consensus sequences

The AP-1 consensus sequences (TGAGTCA) are the major 12-O-tetradecanoylphorbol113-acetate (TPA) responsive elements shared by several TPA inducible genes, such as c-sis, c-fos, c-myc, collagenase, stromelysin, hMTIIA and SV40. However, the role of AP-1 binding sites, which are present in the introns 3, 5, and 11 of ODC gene, in the regulation of TPA-induced ornithine decarboxylase (ODC) gene transcription are unknown. We determined the TPA responsiveness of the AP-1 sequences in the introns of ODC gene in CV-1 cells which induce ODC activity and mRNA in response to TPA treatment. ODC introns containing AP-1 sequences were inserted into the chloramphenicol acetyltransferase (CAT) reporter gene. Transient transfection of CV-1 cells with the intron-CAT constructs followed by TPA treatment did not induce CAT activity. However, when flanking regions of the AP-1 site in intron 3 were narrowed down to 74 bp, TPA induced CAT activity by 5- to 7-fold. The TPA-inducibility could be eliminated by mutation of the AP-1 site (TGAGTCA-->TGATGCCA or TGATGA) in 74 bp of intron 3. These results indicate that the AP-1 sequences in the intact ODC introns may not be responsive to TPA. The flanking sequences of the AP-1 site may be crucial to determine whether the AP-1 site is accessible to the TPA-induced transcriptional factor(s).

Management of giardiasis by an immuno-modulatory herbal drug Pippali rasayana

Pippali rasayana (PR), an Ayurvedic herbal medicine, prepared from Piper longum (Pippali) and Butea monosperma (Palash), and prescribed for the treatment of chronic dysentery and worm infestations was tested for anti-giardial and immuno-stimulatory activity in mice, infected with Giardia lamblia trophozoites. It produced up to 98% recovery from the infection. The rasayana had no killing effect on the parasite in vitro. It induced significant activation of macrophages as evidenced by increased macrophage migration index (MMI) and phagocytic activity. Enhancement of host resistance could be one of the possible mechanisms contributing towards the recovery of animals from the giardial infection.

Non-AP-1 tumor promoter 12-O-tetradecanoylphorbol-13-acetate-responsive sequences in the human ornithine decarboxylase gene

To define the mechanisms of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transcription of the ornithine decarboxylase (ODC) gene, we isolated a genomic clone (hODC41B) of ODC from a human leukocyte genomic DNA library. The restriction endonuclease map, in comparison with the previously published sequences of the human ODC gene, indicated that hODC41B contained a 15.7-kb sequence that extended from the sixth exon to about 10 kb upstream of the ODC gene. A 2.5-kb genomic fragment containing the 5' flanking region and the first exon was subcloned and sequenced. Sequence analysis revealed multiple putative promoter/enhancer elements (a TATA box, a CAAT box, 17 GC boxes, and a cAMP-responsive element) but no consensus AP-1 sequences (TGAGTCA) in the 2.5-kb 5' flanking region. However, three AP-1 sequences were located in introns 3, 5, and 11. We constructed a series of chimeric genes containing part of the first exon and increasingly longer 5' flanking sequences of the ODC gene fused to either bacterial chloramphenicol acetyltransferase (CAT) or luciferase reporter genes. TPA inducibility was determined by transient transfection and measurement of CAT or luciferase expression in HeLa cells. The induction of CAT activity by TPA decreased with decreasing lengths of the 5' flanking sequences up to nt -82. The TPA induction from the construct -72 ODC CAT was threefold to sevenfold, and the TPA inducibility of the same fragment was about ninefold to 30-fold with the luciferase reporter gene. Further deletion analysis revealed TPA-responsive sequences in ODC nt -42 to +54. Gel mobility shift assays using alpha-32P-end labeled ODC nt -42 to +60 revealed that nt -42 to +60 specifically bound HeLa cell nuclear proteins. HeLa cell nuclear protein binding to ODC nt -42 to +60 could not be completely competed by AP-1-, AP-2-, AP-3-, or SP1-responsive sequences.

Pre and postoperative median nerve conduction in patients with pituitary tumour

A study of median nerve sensory conduction at the wrist was performed in 34 patients with pituitary adenomas prior to and following surgery. In 31 patients this was done bilaterally. They included 11 patients with acromegalic features, 3 of whom had features of carpal tunnel syndrome. Six out of 11 (55%) acromegalics had abnormal latencies and conduction velocities pre-operatively. Among the remaining patients only 3 had conduction delay pre-operatively. Postoperative improvement in conduction velocity and latency was recorded in 24 patients although significant improvement was observed in only 13 patients. All 3 patients with carpal tunnel syndrome had significant improvement in conduction velocities and latencies following the surgery. There was no definite relationship between conduction velocity and the pre-operative hormonal profile.

Fine needle aspiration cytology of salivary gland lesions

247 salivary gland lesions were subjected to fine needle aspiration (FNA) cytology; 179 were designated as neoplastic lesions and 68 as non-neoplastic. Based on cytomorphologic features, the neoplastic and non-neoplastic lesions were subcategorised. All but 36 of the neoplastic lesions were subjected to histopathologic study. The overall diagnostic accuracy of FNA cytology for neoplastic lesions was 91%. The sensitivity rate for detecting malignant tumours was 87.8% and the specificity 98.0%. There was 100% sensitivity for cytodiagnosis of benign tumours. The high sensitivity and specificity of cytodiagnosis makes FNA cytology a valuable diagnostic modality in the evaluation of salivary gland lesions.

Involvement of protein kinase C in the transcriptional regulation of 12-O-tetradecanoylphorbol-13-acetate-inducible genes modulated by AP-1 or non-AP-1 transacting factors

The involvement of protein kinase C (PKC), a 12-O-tetradecanoylphorbol-13-acetate (TPA) receptor, in the transcriptional regulation of TPA-inducible genes was determined. Expression plasmids harboring full-length or kinase domain of PKC alpha and PKC delta (PKC alpha K and PKC delta K) were constructed. Transient transfection of PKC alpha K and PKC delta K into COS cells resulted in approximately 20- and 16-fold increase in phospholipid-, calcium-independent protein kinase activity. To determine the effects of overexpression of PKC alpha K and PKC delta K on the AP-1-mediated TPA-inducible genes, we transfected into COS cells the PKC alpha K or PKC delta K expression plasmids with collagenase chloramphenicol acetyltransferase (CAT) reporter construct containing one TPA responsive element (TRE), or a construct containing five synthetic TRE linked to a thymidine kinase promoter. PKC alpha K or PKC delta K overexpression resulted in a comparable increase (approximately 4-fold) in CAT activity. However, CAT activity was not increased after transfection of PKC constructs with non-TPA responsive thyroid hormone responsive elements CAT construct (delta MTV-TyRE-pCAT). We also found that deletion of the AP-1-like motif in the SV40 promoter abolished the PKC alpha K or PKC delta K-induced activity of luciferase (luc) reporter constructs. Overexpression of full-length PKC delta in COS cells also increased the activity of the CAT construct with TRE after TPA treatment. We determined the effects of overexpression of PKC alpha K and PKC delta K on transcription of the ornithine decarboxylase (ODC) gene, which has a non-AP-1 TRE. Cotransfection of PKC alpha K or PKC delta K expression plasmids with a TPA-inducible ODC luc construct (-72/+130-ODC-luc) into HeLa cells resulted in an increased luc activity. These results indicate that both PKC alpha (calcium dependent) and PKC delta (calcium independent) may mediate the transcription of TPA-inducible genes through both AP-1 and non-AP-1 sequences.

Retinoic acid nuclear receptors and tumor promotion: decreased expression of retinoic acid nuclear receptors by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate

During studies to determine the mechanism of tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA), we found that TPA downregulates mouse epidermal retinoic acid nuclear receptors (RAR), a superfamily of nuclear steroid/thyroid receptors implicated in mediating effects of retinoic acid (RA). Application of TPA to mouse skin decreased the binding of [3H]RA to RAR from mouse epidermal nuclear extracts. In this experiment, 20 nmol of TPA was applied to mouse skin and 3.5 h later binding of [3H]RA to RAR was analyzed by chromatography on a size-exclusion column. TPA treatment resulted in an approximately 67% decrease in the specific binding of [3H]RA to RAR. In a more detailed time course, application of 20 nmol of TPA to mouse skin led to 20, 36, 92 and 0% decrease in the binding of [3H]RA to mouse epidermal RAR at 2, 4, 12 and 72 h after treatment respectively. Okadaic acid, an inhibitor of protein phosphatases 1 and 2A but a mouse skin tumor promoter, also inhibited the binding of RA to RAR. RAR alpha and RAR gamma, but not RAR beta mRNA, could be detected in mouse epidermis. In addition, RA nuclear receptor RXR alpha was also expressed in the mouse epidermis. As determined by Northern blot analysis of total as well as poly(A)+ RNA, application of 10 nmol of TPA to mouse skin led to decreased expression of RAR alpha, RAR gamma and RXR alpha mRNA at 3.5 h after treatment. The effect of TPA on the attenuation of RAR expression was specific. Specific binding of RA to RAR was decreased when TPA-induced expression of the c-fos, c-jun and ornithine decarboxylase gene was increased. Downregulation of RAR(s) may be an essential component of the mechanism of mouse skin tumor promotion.

The mechanism of the inhibition of squamous differentiation of rat tracheal 2C5 cells by retinoic acid

Retinoic acid (RA) plays an essential role in maintaining normal differentiation of tracheal epithelial cells. During vitamin A deficiency, tracheocytes undergo squamous metaplasia, an abnormal differentiation that can be reversed by RA. We used rat tracheal 2C5 cells to study the mechanism of inhibition of squamous differentiation by RA. 2C5 cells grown to confluence in the presence of serum underwent squamous differentiation as marked by an increase in their level of crosslinked envelope formation. The serum-induced crosslinked envelope formation was blocked by RA in 2C5 cells with an ED50 < 0.1 nM. However, the activity of the crosslinking enzyme, keratinocyte transglutaminase, did not correlate with the formation of crosslinked envelopes in 2C5 cells. Changes in biochemical markers of squamous differentiation such as an altered expression of specific cytokeratins also accompanied serum-induced squamous differentiation of 2C5 cells. The expression of the keratin squamous differentiation markers (i.e. K13) were inhibited by RA, although the ED50 for K13 expression was > 1 nM. The different dose responses for RA inhibiting differentiation markers suggests multiple mechanisms of regulation by RA. These results indicate that 2C5 cells remain responsive to differentiation factors such as RA and serum despite being an immortalized cell line.