Tubular adenosis of the breast. A distinctive benign lesion mimicking invasive carcinoma

Tubular adenosis, a term first coined by Oberman, is an uncommon benign lesion of the breast that may mimic invasive carcinoma. There is no formal description of this condition in the literature. We report the findings on six specimens from five patients (one with bilateral disease), including three that showed cancerization by intraductal carcinoma (DCIS). The ages of the patients ranged from 40 to 82 years. One patient presented with a 3-cm breast mass, and the others were found in specimens resected for infiltrating ductal carcinoma (two specimens) or DCIS (three specimens). The histologic hallmark of tubular adenosis was haphazard proliferation of elongated tubules that were noncrowded, narrow, and sometimes branching. There was no lobular arrangement or, at most, vague lobular grouping, with some tubules often extending into the fat. The tubules contained basophilic or granular eosinophilic secretion. The stroma was sclerotic to edematous. The tubules were lined by bland-looking ductal cells and were surrounded by an intact myoepithelial layer, a phenomenon well highlighted by immunostaining for muscle-specific actin (HHF-35) or S-100 protein. In three specimens, the tubular adenosis was cancerized by noncomedo DCIS, producing a pattern strongly mimicking infiltrating carcinoma; the in situ nature of the carcinoma was confirmed by actin immunoreactivity in the residual myoepithelium as well as by the presence of architecturally similar tubular adenosis in the vicinity. Tubular adenosis shows an infiltrative growth similar to microglandular adenosis and adenomyoepithelial adenosis, but it differs from them by the interdigitating tubular configuration and also differs from microglandular adenosis by the presence of myoepithelium. Tubular adenosis can be distinguished from sclerosing adenosis by the lack of obvious lobular architecture or whorled arrangement and wider separation of the tubules. Tubular adenosis appears to be a benign lesion per se, but whether it has premalignant potential remains to be determined. The importance of recognizing this entity lies in its being potentially mistaken for invasive carcinoma, especially at intraoperative frozen section or when the lesion is cancerized by DCIS.

Increased bioavailability of clomipramine after sublingual administration in rats

This study examined the absorption and disposition of clomipramine in rats after sublingual (5 and 50 mg/kg), oral (50 mg/kg), and iv (5 mg/kg) administration. The mean oral bioavailability of clomipramine was 24.8% and 29.7%, respectively, in conscious rats and in rats anesthetized with ketamine/xylazine (30/3 mg/kg). When given sublingually in isotonic saline at a dose of 50 mg/kg, clomipramine was rapidly absorbed, and the mean absolute bioavailability (36.2%) was increased over oral dosing. The mean AUC values of clomipramine were 2258 +/- 1762 ng.h/mL and 1891 +/- 867 ng.h/mL after oral administration to conscious and anesthetized rats, respectively, and 3303 +/- 1576 ng.h/mL after sublingual administration to anesthetized rats. Sublingual administration (5 mg/kg doses) of clomipramine formulated with a permeation enhancer, 2-hydroxypropyl beta-cyclodextrin, further increased the sublingual bioavailability to 57.1%. The sublingual route may be an alternative route of administration of clomipramine, providing enhanced bioavailability.

Regulation of Fc epsilon receptor 2 (CD23) expression on a human eosinophilic cell line EoL3 and a human monocytic cell line U937 by transforming growth factor beta

Regulation of low-affinity receptors for IgE (Fc epsilon R2/CD23) on a human eosinophilic cell line EoL3 and a human monocytic cell line U937 was studied using an anti-Fc,R2/CD23 monoclonal antibody H107 by flow cytometry. While platelet-activating factor, interleukin 4, and interferon gamma significantly augmented Fc epsilon R2/CD23 expression on both cell lines, transforming growth factor beta (TGF beta) inhibited both the basal level of Fc epsilon R2/CD23 expression and the enhanced Fc epsilon R2/CD23 expression induced by these reagents in dose- and time-dependent manners. However, TGF beta did not significantly suppress the high basal level of Fc epsilon R2/CD23 expression on RPMI 8866 cells. These results suggest that Fc epsilon R2/CD23 expression on EoL3 and U937 cells is regulated by various cytokines and growth factors, and that TGF beta plays an important regulatory role in IgE-mediated immune responses.

Neurosurgical application of fibrin adhesive

We have tried fibrin adhesive, which mimics the end stage of plasmatic coagulation, in 26 patients with various neurosurgical problems such as: repair of cerebrospinal fluid (CSF) leaks, sealing of the vascular anastomosis sites, reinforcements of aneurysmal clippings, and hemostasis after resection of brain tumors. Presented in this report are 11 intracranial aneurysms, 11 brain tumors, 2 lipomyelo-meningoceles, and one each of cerebral arteriovenous malformation and torn dura resulting from a mastoidectomy. Procedures which seemed to be impossible or very difficult by conventional neurosurgical techniques could be accomplished in all cases without any complication. Our experience with fibrin adhesive suggests that it is a valuable adjuvant to various microneurosurgical procedures, and it may be potentially useful for protection of major cerebral veins and venous sinuses during cerebral retraction.

Breakage of resistance to Cucumber mosaic virus by co-infection with Zucchini yellow mosaic virus : enhancement of CMV accumulation independent of symptom expression

Resistance to the cucumovirus Cucumber mosaic virus (CMV) in cucumber cv. Delila was manifested as a very low level of accumulation of viral RNA and capsid protein, and an absence of CMV-induced symptoms. In addition, resistance was observed at the single cell level, with a reduction in accumulation of CMV RNAs, compared to accumulation in cells of the susceptible cucumber cv. Bet Alpha. Resistance to CMV in cv. Delila was broken by co-infection with the potyvirus Zucchini yellow mosaic virus (ZYMV). Resistance breakage in cv. Delila plants was manifested by an increase in the accumulation of (+) and (-) CMV RNA as well as CMV capsid protein, with no increase in the level of accumulation of ZYMV. Resistance breakage in the resistant cultivar by ZYMV also occurred at the single cell level. Thus, synergistic interactions known to occur between a potyvirus and a cucumovirus led to resistance breakage during a double infection. However, resistance breakage was not accompanied by an increase in disease symptoms beyond those induced by ZYMV itself. On co-inoculation with an asymptomatic variant of ZYMV-AG an enhancement of CMV infection occurred without disease manifestation. Consequently, intensification of viral RNA and capsid protein accumulation can occur without a corresponding increase in disease development, suggesting that different host genes regulate viral accumulation and disease development in the CMV-resistant cucumber plants.

Side-chain structure and dynamics at the lipid-protein interface: Val1 of the gramicidin A channel

High resolution dynamics and structural information has been resolved from 2H solid-state NMR spectra of the Val-1 side-chain of the gramicidin channel in a lipid bilayer. Both powder pattern lineshapes and spectra from uniformly aligned samples of gramicidin in lipid bilayers have been analyzed to achieve a fully consistant interpretation of the data. Torsional motions about the C alpha C beta axis (chi 1) are shown to be three-state jumps in which the occupancy of the states is given by the ratio, 75:15:10 for the chi 1 angles of 184 degrees:304 degrees:64 degrees. The dominant conformer is also the most common conformation observed for valines in well defined protein structures. The distribution of conformational substates that represents the chi 1 dynamics appears to be largely independent of the lipid phase transition and the hydration of the sample. However, there is evidence that the residence time between jumps is dependent on the lipid phase transition. Although this time is shown to be approximately 1 microseconds below the phase transition temperature, it is in the fast exchange limit above the transition temperature.

Increased safety by two-stage hepatectomy with preoperative portal vein embolization in rats

We evaluated the usefulness of preoperative portal vein embolization (PVE) in rats for increasing the safety of liver resection. During PVE, portal vein branches that perfused the central and left lobes of the liver were embolized. Liver weight, the elimination of indocyanine green, and the number of Kupffer cells were examined 7 days after PVE and in intact rats. Then we examined rats that had undergone PVE (PVE group), rats in which the embolized part of the liver was resected 7 days after PVE (PVE-Hx group), rats without PVE in which the same lobes of the liver were resected (Hx group), and rats that had undergone a sham operation (sham-operation group) for liver weight, the mitotic index of the hepatocytes, serum alanine aminotransferase activity, total bilirubin, and antithrombin III activity. Some rats in the four groups received an intravenous injection of 0.5 or 2.5 mg/kg endotoxin 48 hr after the operation (the second operation, if done), and the 24-hr survival rate was calculated. Some rats given 0.5 mg/kg endotoxin were killed 6 hr after the injection, and the extent of liver injury was examined biochemically and histologically. Seven days after PVE, the nonembolized part of the liver was about twice the weight of the corresponding lobes in the intact rats, the density of Kupffer cells was doubled, and the hepatic function per unit weight was about the same as that in these controls. Hepatic dysfunction and the endotoxin-induced liver injury were significantly slighter in the PVE and PVE-Hx groups than in the Hx group. Preoperative PVE could make hepatectomy safer.

Pharmacokinetic disposition of polyethylene glycol-modified salmon calcitonins in rats

This study first reports the pharmacokinetic disposition of polyethylene glycol (PEG)-modified salmon calcitonin (sCT) based on the number of attached PEG molecules. PEG-modified sCT was prepared by covalent linkage with succinimidyl carbonate monomethoxy polyethylene glycol. Mono- and di-PEG-sCTs were separated by size exclusion and reverse phase HPLC, and radioiodinated by the chloramine-T method with Na125I. 125I-mono-PEG sCT, 125I-di-PEG-sCT and unmodified 125I-sCT were administered to rats by i.v. injection. Serial blood samples, urine and various tissue samples were taken for the determination of radioactivity. Di-PEG-sCT exhibited significantly reduced systemic clearance (2.3 vs. 11.1 ml/min/kg) and steady-state volume of distribution (229.9 vs. 603.1 ml/kg), while mono-PEG-sCT showed a prolonged elimination half-life (189.1 min vs. 59.8 min) compared with unmodified sCT. The extent of urinary excretion of the PEG-modified sCTs was higher than for the unmodified sCT, but all these chemicals were excreted in urine in small quantities (< or = 0.6%). There was a tendency toward reduced accumulation of PEGylated sCTs in tissues, with its reduction being inversely proportional to the molecular size. Accumulation of the total radioactivity of the unmodified and PEG-modified sCTs was highest in the liver, followed by kidneys, lungs, spleen, heart and thyroid. When expressed per tissue gram weight, however, the highest radioactivity was found in the kidneys. PEGylated sCTs may have greater therapeutic potential via reduced systemic clearance and prolonged elimination half-life over unmodified sCT.

Ligand-dependent conformational plasticity of the periplasmic histidine-binding protein HisJ. Involvement in transport specificity

The periplasmic histidine permease of Salmonella typhimurium is composed of a membrane-bound complex and a soluble histidine-binding protein (the periplasmic receptor), HisJ. Liganded receptor interacts with the membrane-bound complex, inducing ATP hydrolysis and substrate translocation. Preliminary evidence had shown a lack of direct correlation between the affinity of HisJ for a ligand and translocation efficiency, suggesting that the precise form of the receptor is important in determining its interaction with the membrane-bound complex. We have investigated the nature of the conformations assumed by HisJ upon binding a variety of ligands by tryptophan fluorescence enhancement, reaction with a closed form-specific monoclonal antibody, and changes in UV absorption spectra. It is demonstrated that although HisJ binds all the ligands and undergoes a conformational change, it assumes measurably different conformations. We also show that the interaction between HisJ and the membrane-bound complex depends on the nature of the ligand. Transport specificity appears to be defined, at least in part, by the conformation of the bound receptor, manifested either by the effect of a given ligand on the closed structure per se, or by the effect of ligand association on the equilibrium constant relating the open and the closed liganded forms.

Mechanisms of histamine-induced intracellular Ca 2+ release and extracellular Ca 2+ entry in MG63 human osteosarcoma cells 1 1Abbreviations: [Ca2+]i; Cytosolic free Ca2+ concentration; and IP3, inositol 1,4,5-trisphosphate

The effect of histamine on intracellular free Ca2+ levels ([Ca2+](i)) in MG63 human osteosarcoma cells was explored using fura-2 as a Ca2+ dye. Histamine increased ([Ca2+](i)) in a concentration-dependent fashion with an EC(50) value of 0.5 microM. Extracellular Ca2+ removal inhibited the ([Ca2+](i)) signals. Histamine failed to increase ([Ca2+](i)) in Ca2+-free medium after cells were pretreated with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Addition of Ca2+ induced concentration-dependent ([Ca2+](i)) increases after preincubation with histamine in Ca2+-free medium. Histamine-induced intracellular Ca2+ release was abolished by inhibiting phospholipase C with 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). The ([Ca2+](i)) increase induced by histamine in Ca2+ medium was abolished by cimetidine, but was not altered by pyrilamine, nifedipine, verapamil, and La(3+). Together, this study shows that histamine increased in ([Ca2+](i)) in osteosarcoma cells by stimulating H2 histamine receptors. The Ca2+ signal was caused by Ca2+ release from the endoplasmic reticulum in a phospholipase C-dependent manner. The Ca2+ release was accompanied by Ca(2+) influx.

Relationship between tissue plasminogen activator, plasminogen activator inhibitor and CT image in chronic subdural hematoma

The present study was performed to investigate the relationship between the concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) and the CT images in 23 cases of chronic subdural hematomas (SDHs). The concentrations of t-PA and PAI-1 were quantified by enzyme-linked immunosorbent assay (ELISA). Chronic SDHs were divided into five groups according to their appearance on computed tomography: high-density (n = 4), isodensity (n = 8), low-density (n = 5), mixed-density (n = 3), layering (n = 3) types. The volume of hematoma was measured with an image analyzing software program. The concentrations of t-PA were higher in layering (41.2 +/- 0.3 ng/ml, mean +/- standard error of the mean) and high-density (40.0 +/- 1.1 ng/ml) types compared to those of low-density (23.3 +/- 4.1 ng/ml) and iso-density (25.1 +/- 3.7 ng/ml) types. The concentrations of PAI-1 were lower in layering (95.9 +/- 1.0 ng/ml) and high-density (103.4 +/- 34.5 ng/ml) types compared to that of low-density (192.5 +/- 2.6 ng/ml) type. So the ratio between t-PA and PAI-1 (t-PA/PAI) was greater in layering and high-density types. The volume of hematoma was larger in mixed-density and layering types but statistically insignificant. These results presumably suggest that the ratio between t-PA and PAI concentration may contribute to the pathogenesis of the chronic SDH.

High frequency of thyroid tumor induction by N-methyl-N'-nitro-N-nitrosoguanidine in the hermaphroditic fish Rivulus marmoratus

In the self-fertilizing hermaphroditic fish, Rivulus marmoratus, the susceptibility to tumor induction by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was evaluated. Seven-day-old fish larvae were exposed for 2 h to MNNG at concentrations ranging from 5 to 25 ppm in a static water bath. The exposed fish were observed at 2 and 4 months after carcinogen treatment to assess tumor development. Within 4 months after 25 ppm MNNG exposure, nearly all fish developed thyroid tumors. The tumor incidences were dose- and time-dependent, and the latent period of tumor induction was less than 2 months. Most induced neoplasms were papillary carcinomas similar histologically to those of rodents and humans, and the tumors were serially transplantable to other fish of the same species. These results demonstrate that rivulus could be useful as a model of thyroid carcinogenesis.

Analysis of 69 patients with amebic liver abscess

All 69 patients with amebic liver abscess that we treated in 1981-1992 were studied retrospectively. Men predominated by a 10:1 ratio. Of our 227 patients with amebiasis, some 30% yearly had liver involvement. The incidence peaked in 1988, decreasing later but increasing again in 1992. Most patients were 30-50 years old, the overall mean age being 45 years (range, 22-79), and decreasing with time. Patients with the related factors of travel abroad, positive results of a test for Treponema pallidum hemagglutination, and homosexuality have increased in number in recent years. Fever, abdominal pain, and hepatomegaly were the most frequent findings, and 39 patients had neither bloody stools nor diarrhea. Only 8 patients had had amebiasis previously. A solitary abscess in the right lobe of the liver was found in 40 patients. Entamoeba histolytica was found in the stool of 31 patients and in the pus of 39 patients. Sixty-one patients had positive results for an amebic serological test(s). The abscesses ruptured into the peritoneal cavity in 4 patients. All patients received metronidazole. Percutaneous or surgical drainage (or both) was done in 62 patients. The outcome was good, with 1 exception, and only 2 patients had recurrences.

Posttransplantation lymphoproliferative disorder in patients under primary tacrolimus (FK 506) immunosuppression

Posttransplantation lymphoproliferative disorder (PTLD) is a well-described complication of the systemic immunosuppression required for successful organ transplantation. Lesions of PTLD often occur in the region of the head and neck and require otolaryngologic evaluations. Although the majority of reported cases of PTLD are associated with cyclosporine immunosuppression, recently, PTLD has been described in patients treated solely with the newer systemic immunosuppressive agent tacrolimus (FK 506). As an introduction to tacrolimus and to PTLD as one of its complications, a case of PTLD presenting as airway obstruction in a child treated solely with tacrolimus immunosuppression is described. In addition, a review of tacrolimus and PTLD in patients under tacrolimus immunosuppression is presented to familiarize the otolaryngologist with this important new immunosuppressive agent and a potential complication of its use.

Extraskeletal chondroma with lipoblast-like cells

An extraskeletal chondroma occurring over the dorsum of the wrist of a 61-year-old woman is reported. The lobulated tumor is cellular and shows mild-to-moderate nuclear pleomorphism of the chondroid cells. A unique feature is that some tumor cells are univacuolated and multivacuolated owing to accumulation of lipid, mimicking the appearances of lipoblasts.

Juvenile-onset glycogen storage disease type II with novel mutations in acid alpha-glucosidase gene

The authors describe two novel mutations of the acid alpha-glucosidase gene, P361L and R437C, which define the juvenile-onset glycogen storage disease type II (GSDII) in a 16-year-old Chinese patient. The asymptomatic 13-year-old brother of the proband is also a compound heterozygote of the two mutations. These results confirm that intrafamilial phenotypic variation of juvenile-onset GSDII is ethnically diverse and suggest the contribution of other genes to the phenotypic variability of GSDII.

Regulation of bcl-2 family in hydrogen peroxide-induced apoptosis in human leukemia HL-60 cells

Numerous types of cells have been shown to undergo apoptosis when exposed to oxidant agent such as hydrogen peroxide. In order to understand the functional relationship between the anti- and pro-apoptotic regulatory proteins in the cells under oxidant stress, we have studied the level of expression of apoptosis regulatory proteins, bcl-2 and bax, in human leukemia HL-60 cells. The exposure of HL-60 cells to different concentrations of H2O2 for 6 h resulted in a typical apoptosis of the cells as characterized by flow cytometry, cell cycle analysis, and DNA fragmantation. There was a block in G1 to S transition and apoptotic cells were mainly derived from S and G2 cells. Kinetic study demonstrated that the levels of both bcl-2-mRNA and -protein expression were decreased with the progression of cellular apoptosis whereas the level of bax-mRNA was unchanged but the expressed bax-protein was not detectable. Cycloheximide, a nonspecific translation inhibitor, did not prevent the hydrogen peroxide-mediated apoptosis in HL-60 cells. These results suggest that the regulation of bcl-2, but not of bax are important factor in the oxidative stress-induced apoptosis in HL-60 cells.

Rapidly-frozen polypeptide samples for characterization of high definition dynamics by solid-state NMR spectroscopy

A method is described for defining anisotropic local dynamics in polypeptides by solid-state NMR. To avoid conformational heterogeneity introduced by large hexagonal ice crystals in low temperature hydrated samples, a fast-freezing technique is used for sample preparation. For a demonstration of this approach, the backbone librational motions of the gramicidin A channel conformation are studied in hydrated DMPC bilayers. The static 15N chemical shift tensor is characterized at 123 K for the Ala3 site. The temperature dependence of this tensor yields a determination of the librational amplitude and anisotropy of the motionally sampled space. This amplitude represents the sum of nanosecond and picosecond time-frame motions, both of which have a significant amplitude.

Intercalating TOP2 Poisons Attenuate Topoisomerase Action at Higher Concentrations

Topoisomerase II (TOP2) poisons are effective cytotoxic anticancer agents that stabilize the normally transient TOP2-DNA covalent complexes formed during the enzyme reaction cycle. These drugs include etoposide, mitoxantrone, and the anthracyclines doxorubicin and epirubicin. Anthracyclines also exert cell-killing activity via TOP2-independent mechanisms, including DNA adduct formation, redox activity, and lipid peroxidation. Here, we show that anthracyclines and another intercalating TOP2 poison, mitoxantrone, stabilize TOP2-DNA covalent complexes less efficiently than etoposide, and at higher concentrations they suppress the formation of TOP2-DNA covalent complexes, thus behaving as TOP2 poisons at low concentration and inhibitors at high concentration. We used induced pluripotent stem cell (iPSC)-derived human cardiomyocytes as a model to study anthracycline-induced damage in cardiac cells. Using immunofluorescence, our study is the first to demonstrate the presence of topoisomerase IIβ (TOP2B) as the only TOP2 isoform in iPSC-derived cardiomyocytes. In these cells, etoposide robustly induced TOP2B covalent complexes, but we could not detect doxorubicin-induced TOP2-DNA complexes, and doxorubicin suppressed etoposide-induced TOP2-DNA complexes. In vitro, etoposide-stabilized DNA cleavage was attenuated by doxorubicin, epirubicin, or mitoxantrone. Clinical use of anthracyclines is associated with cardiotoxicity. The observations in this study have potentially important clinical consequences regarding the effectiveness of anticancer treatment regimens when TOP2-targeting drugs are used in combination. These observations suggest that inhibition of TOP2B activity, rather than DNA damage resulting from TOP2 poisoning, may play a role in doxorubicin cardiotoxicity. SIGNIFICANCE STATEMENT: We show that anthracyclines and mitoxantrone act as topoisomerase II (TOP2) poisons at low concentration but attenuate TOP2 activity at higher concentration, both in cells and in in vitro cleavage experiments. Inhibition of type II topoisomerases suppresses the action of other drugs that poison TOP2. Thus, combinations containing anthracyclines or mitoxantrone and etoposide may reduce the activity of etoposide as a TOP2 poison and thus reduce the efficacy of drug combinations.

Transurethral needle ablation for chronic nonbacterial prostatitis

OBJECTIVE

To investigate the efficacy of transurethral needle ablation (TUNA) of the prostate for treating chronic nonbacterial prostatitis unresponsive to conservative therapies.

PATIENTS AND METHODS

Forty-two patients (mean age 38.5 years, range 25-52) with nonbacterial prostatitis in whom clinical management was unsuccessful in relieving the symptoms or signs of prostatitis were treated using TUNA. All patients had a high leukocyte count (> 15 per high-power field) in expressed prostatic secretions (EPS) with no bacterial growth in either urine or prostatic secretion cultures. Before TUNA all patients were evaluated using a symptom score, satisfaction score (quality of life) and an examination of prostatic secretions. All patients were reassessed using the same variables 1 and 3 months after TUNA. Of the 42 patients, 10 had their semen analysed before and 3 months after treatment.

RESULTS

The mean (sd) symptom and satisfaction scores improved significantly, from 11.02 (2.90) to 5.00 (2.61) and from 4.84 (0.57) to 1.26 (1.18), respectively, 3 months after TUNA (both P < 0.05). Of the 42 patients, 30 (71%) had normal EPS results within 3 months of TUNA. Also, of 37 patients with high leukocyte counts (> 100 per high-power field) before TUNA, 26 (70%) had normal EPS results within 3 months afterward, and 29 (78%) had a satisfaction score of < 3 points.

CONCLUSIONS

TUNA may be a possible treatment option for patients with chronic nonbacterial prostatitis that is unresponsive to conservative therapies. A long-term follow-up and randomized studies are needed to confirm the efficacy of the TUNA against intractable chronic prostatitis.

Do clinical breast examination skills improve during medical school?

PURPOSE

To assess the effects of stage of training, gender, and specialty interest on medical students' breast cancer knowledge, attitudes, and clinical breast examination (CBE) skills as a case study of the progression of physical examination skills during medical education.

METHOD

In 1996, questionnaires assessing breast cancer knowledge and attitudes were administered to 493 premedical and first-, second-, and third-year medical students at Northwestern University Medical School. Silicone breast models were used to evaluate the CBE proficiency of a subset of 151 students.

RESULTS

Breast cancer knowledge was positively correlated with stage of training (r = .62), with significant differences between all levels (p < .001). In contrast, first-year medical students attained the highest mean lump-detection sensitivity (61.5%), followed by second-year (53.9%) and third-year (43.5%) students (p < .001, first- vs third-year students; p < .10, second- vs third-year students). There was no significant difference in specificity among the four stages.

CONCLUSIONS

The results suggest that breast cancer knowledge and attitudes are not related to CBE proficiency, which is a practiced tactile skill. The decline in lump-detection sensitivity with increased stage of training may demonstrate the need for increased attention to palpation skills during the clinical years. These findings are consistent with those of earlier reports that suggest the need for the reinforcement of physical examination skills during clinical education.

PEGylation improves the hypoglycaemic efficacy of intranasally administered glucagon-like peptide-1 in type 2 diabetic db/db mice

AIMS

PEGylation - covalent modification of therapeutic peptides with polyethylene glycol (PEG) - is viewed as an effective way of prolonging the short lifetime of glucagon-like peptide-1 (GLP-1). In this study, we investigated the hypoglycaemic efficacies of PEGylated GLP-1s administered intranasally in type 2 diabetic db/db mice.

METHODS

Three types of site-specific (Lys(34)) PEGylated GLP-1 analogues (PEG molecular weight: 1, 2 or 5 kDa) were synthesized. Their metabolic stabilities were evaluated in nasal mucosa enzyme pools. Oral glucose tolerance test was conducted 30, 60 and 120 min after intranasally administering these analogues in type 2 diabetic db/db mice.

RESULTS

PEGylated GLP-1 analogues were found to have significantly longer half-lives than native GLP-1 in nasal mucosa enzymes (2.4-fold to 11.0-fold, p < 0.005). Non-PEGylated GLP-1 at 100 nmol/kg was not found to have marked efficacy irrespective of nasal administration time [total hypoglycaemic degree (HD(total)) values 2.8-17.3%]. On the contrary, PEGylated GLP-1s (100 nmol/kg) showed obvious efficacies with maximum HD(total) values of >51.8 +/- 5.8% (p < 0.005 vs. GLP-1).

CONCLUSION

This study highlights the pharmacological potential of intranasally administered PEGylated GLP-1s in terms of stabilizing postprandial hyperglycaemia in type 2 diabetic patients.

Mechanism underlying histamine-induced intracellular Ca2+ movement in PC3 human prostate cancer cells

The effect of histamine on intracellular free Ca2+ levels ([Ca2+]i) in PC3 human prostate cancer cells and the underlying mechanism were evaluated using fura-2 as a Ca2+ dye. Histamine at concentrations between 0.1 and 50 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 value of 1 microM. The [Ca2+]i response comprised an initial rise and a slow decay, which returned to baseline within 3 min. Extracellular Ca2+ removal inhibited 50% of the [Ca2+]i signal. In the absence of extracellular Ca2+, after cells were treated with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), 10 microM histamine did not increase [Ca2+]i. After pretreatment with 10 microM histamine in a Ca2+-free medium for several minutes, addition of 3 mM Ca2+ induced [Ca2+]i increases. Histamine (10 microM)-induced intracellular Ca2+ release was abolished by inhibiting phospholipase C with 2 microM 1-(6-((17 beta-3- methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), and by 10 microM pyrilamine but was not altered by 50 microM cimetidine. Collectively, the present study shows that histamine induced [Ca2+]i transients in PC3 human prostate cancer cells by stimulating H1 histamine receptors leading to Ca2+ release from the endoplasmic reticulum in an inositol 1,4,5-trisphosphate-dependent manner, and by inducing Ca2+ entry.