Roles of growth factors in mediating mesenchymal influence on the cytodifferentiation of the Dunning prostatic adenocarcinoma

Earlier studies have shown that seminal vesicle mesenchyme (SVM) has the ability to induce Dunning tumor (DT) to undergo morphogenetic changes and cytodifferentiation. The aim of the present study was to investigate the roles of growth factors and their receptors in tumor-mesenchymal interactions. Small pieces of DT were combined with SVM (0-day neonatal SD rat) and the tissue recombinants (SVM + DT) were grafted under the renal capsule of male athymic nude mice and allowed to grow for 4 weeks. Histopathological examination confirmed that SVM can induce DT to express apparently more normal morphological features, with the formation of large tubules lined by highly differentiated columnar epithelial cells and the reappearance of a fibromuscular stroma. Using immunohistochemistry, the results demonstrated that the tissue recombinants typically exhibited an overexpression of EGF, EGF-R, bFGF, TGF-beta(1) together with a concurrent downregulation of TGF-alpha, IGF-I, IGF-II, and VEGF receptors (flk-1, flt-1). The levels of these growth factors and their receptors in DT + SVM tissue recombinants were more similar to those of the normal prostate. These findings reaffirmed that SVM has the ability to reprogram DT toward a more normal direction on one hand, while implicating the importance of cytokines in mesenchyme-induced DT phenotypic changes under in vivo condition on the other hand. This study suggests that these factors and their receptors may be essential mediators in tumor-mesenchymal interactions.

Expression of a kallikrein-like protein in prostatic intraepithelial neoplasia in ventral prostate of the noble rat

BACKGROUND

In an effort to identify biomarker(s) for prostatic cancer (PCa), we analyzed the changes of secretory proteins in the ventral prostate (VP) of Noble rats at early stages of carcinogenesis.

METHODS

Ventral prostates were removed from both control (n = 36) and experimental (n = 88) rats implanted with a known ratio of testosterone (T) and 17beta-estradiol (E(2)). Tissue sections were stained by hematoxylin and eosin (H&E) for pathological screening, and secretions were collected for SDS-PAGE analysis followed by N-terminal microsequencing, antiserum production, Western blot, and immunohistochemical study.

RESULTS

Pathologically, low-grade prostatic intraepithelial neoplasia (LGPIN) and high-grade PIN (HGPIN) were observed in ducts or alveoli after 3 and 5 months of T + E(2) treatment, respectively. The results of SDS-PAGE showed an elevated expression of 18-kDa protein (p18) in secretions of VP with HGPIN or cancerous lesions. Analysis of p18 by N-terminal sequencing showed a high score of homology to rat glandular kallikrein. To characterize the expression pattern of the protein in tissue samples, an antiserum was raised against the N-terminus of the p18. The monospecificity of the antiserum against p18 was confirmed by Western blot analysis. Immunohistochemical study showed that in ducts or alveoli of normal and LGPIN samples, a mild positive staining for p18 was observed in secretions. However, the reactivity was intense not only in luminal secretions but also in some luminal secretory cells in HGPIN and cancer cells as well.

CONCLUSIONS

The high expression of p18 in connection with neoplastic transformation of cells strongly suggests that the potential application of this protein as a marker for early detection of PCa should be further investigated.

Sex hormone-induced mammary carcinogenesis in female Noble rats: expression of TGF-beta1 and its receptors, TGF-alpha, and EGF-R in mammary carcinogenesis

We have established a Noble rat model to explore the mechanisms of hormonal mammary carcinogenesis, in which the role of androgen in promoting mammary carcinogenesis was highlighted. We have also established that stromal-epithelial interactions may be responsible for the promotional effects of testosterone in mammary carcinogenesis. Based on these understandings, in the present study we examined the expression of transforming growth factor beta-1 (TGF-beta1) and its receptors (TGF-beta RI, TGF-beta RII), transforming growth factor alpha (TGF-alpha), and epidermal growth factor receptor (EGF-R) in 'pre-malignant' mammary glands treated with different protocols of sex hormones, as well as in mammary cancers. We observed that TGF-beta1 was strongly expressed in most mammary tumors, whereas TGF-beta RI and TGF-beta RII were negative in most mammary tumor cells. The results from comparative study of 'pre-malignant' glands further showed that when the animals were treated with testosterone, either alone or in combination with 17beta-estradiol, the mammary gland epithelial cells expressed high levels of TGF-beta1. This over-expression of TGF-beta1 can be blocked by flutamide, indicating that testosterone may be responsible for the expression of TGF-beta1 in mammary glands. TGF-beta RI and TGF-beta RII were also expressed strongly in testosterone-treated mammary epithelial cells and only weakly detectable in 17beta-estradiol treated and control mammary epithelial cells. Furthermore, TGF-beta RI and TGF-beta RII were also expressed in stromal cells, both in mammary tumors and in hormone-treated mammary glands. These observations indicate that the mechanism of testosterone in mammary carcinogenesis may be through its regulation of expression of TGF-beta1 and its receptors. On the other hand, TGF-alpha was also expressed in all 39 mammary cancers, while only 81% of the cancers were EGF-R positive. TGF-alpha was also strongly expressed in stromal cells in all three experimental groups, but only moderately expressed in epithelial cells when treated with a combination of testosterone and 17beta-estradiol. By contrast, EGF-R was strongly expressed in epithelial cells in the three experimental groups but negative in stromal cells. Flutamide or tamoxifen was unable to block the expression of TGF-alpha induced by the combined sex hormone treatment. However, they were effective in blocking the expression of TGF-alpha when the animals were treated with testosterone or 17beta-estradiol alone, respectively. These results suggest that both testosterone and 17beta-estradiol may be required for the over-expression of TGF-alpha in the mammary carcinogenesis induced by sex hormones. To our knowledge, this is the first experimental study to explore the regulation of TGF-beta1, TGF-alpha, and their receptors by testosterone and 17beta-estradiol in mammary carcinogenesis.

Co-expression of vascular endothelial growth factor (VEGF) and its receptors (flk-1 and flt-1) in hormone-induced mammary cancer in the Noble rat

Vascular endothelial growth factor (VEGF) is recognized to play a predominant role in breast cancer prognosis. The action of VEGF is mediated by two high-affinity receptors with ligand-stimulated tyrosine kinase activity: VEGFR-1/flt-1 and VEGFR-2/flk-1, which are expressed mainly in vascular endothelial cells. To the best of our knowledge, no previous studies on the expression of these receptors in breast cancer cells has been made. We have established a new animal model for breast cancer, using a combination of 17beta-oestradiol and testosterone as 'carcinogens'. Taking advantage of the animal model, we have demonstrated that mammary cancer cells expressed not only high levels of VEGF but also, surprisingly, its receptors (fit-1 and flk-1) in mammary cancer cells. Intense reactivities to VEGF, flt-1 and flk-1 were observed in mammary cancer cells, especially in invasive mammary carcinoma. Western blot analysis confirmed the increase in flk-1 and flt-1 proteins in induced mammary cancers. Based on these observations, we hypothesize that in mammary cancer, VEGF regulates, in addition to endothelial proliferation and angiogenesis, also growth of cancer cells by an autocrine mechanism mediated through its receptors. To further verify this hypothesis, we investigated the correlation between cellular proliferation and the expression of VEGF, flt-1 and flk-1. Using double-labelling immunocytochemistry, we have shown a correlation between high VEGF activity and Ki-67 expression. The Ki-67 indices in the areas of strong and weak VEGF reactivities were 58.3% and 3.7% respectively. Similarly, there was also a correlation of strong flk-1 and Ki-67 reactivity. The Ki-67 indices for areas of strong and weak flk-1 reactivities were 53.9% and 3.1% respectively. On the other hand, there was a reverse correlation between fit-1 and Ki-67 activities. These results indicate that overexpression of VEGF and flk-1 is correlated with high Ki-67 index. The data, therefore, suggest that VEGF may act as an autocrine growth factor for mammary cancer cells in vivo and this autocrine regulatory role may be mediated through flk-1. The present study is the first report showing that VEGF may act as a growth stimulator for mammary cancer cells.

Expression of C-20, 22 desmolase activity by the human fallopian tube in vitro: evidence for steroidogenesis

With a view to establishing whether cells of the human Fallopian tubes possess the cholesterol side-chain cleavage activity, homogenates of the tubes, obtained from 6 women (39-45 years) following abdominal hysterectomy for benign conditions, were incubated with (7n-3H)-cholesterol as substrate. Controls (n=6, age 40-44 years) were homogenates heated in a boiling water bath for 10 min. Using the reverse-isotope dilution technique, (3H)-pregnenolone was isolated and characterized. No such metabolite was evident in control incubations of heat-denatured enzymes. The extent of enzymic conversion varied from 1.9 x 10(-3) to 1.3 x 10(-2)%. The results reveal for the first time the existence of an active cholesterol-specific C-20, 22 desmolase system in the viable tissues. It is suggested that there exists a potential for substantial pregnenolone synthesis in vivo. This rate-limiting steroid biosynthetic conversion provides a new dimension to the functional capacity of the Fallopian tubes in the synthesis of steroids, which may be necessary for modulating ciliary beat frequency and in maintenance of hormonal milieu essential for embryogenesis.

Radiation dose reduction in paediatric cranial CT

BACKGROUND

There is no consensus about the optimal milliamperage-second (mAs) settings for computed tomography (CT). Most operators follow the recommended settings of the manufacturers, but these may not be the most appropriate settings.

OBJECTIVE

To determine whether a lower radiation dose technique could be used in CT of the paediatric brain without jeopardising the diagnostic accuracy of the images.

MATERIALS AND METHODS

A randomised prospective trial. A group of 53 children underwent CT using manufacturer's default levels of 200 or 250 mAs; 47 underwent scanning at 125 or 150 mAs. Anatomical details and the confidence level in reaching a diagnosis were evaluated by two radiologists in a double-blinded manner using a 4-point scoring system.

RESULTS

For both readers there was no statistically significant difference in the confidence level for reaching a diagnosis between the two groups. The 95 % confidence intervals and P values were -0.9-1.1 and 0.13 (reader 1) and -1.29-1.37 and 0.70 (reader 2), respectively. Reliability tests showed the results were consistent.

CONCLUSIONS

The recommended level may not be the optimum setting. Dose reduction of 40 % is possible on our system in paediatric brain CT without affecting the diagnostic quality of the images.

The sensitivity of the trivariate analysis using maternal serum alpha-feto protein, human chorionic gonadotrophin and maternal age in screening for fetal aneuploidy in mothers above the age of 35

This study was undertaken to assess the usefulness of maternal serum human chorionic gonadotrophin, alpha-fetoprotein and maternal age in screening for fetuses with abnormal chromosomes in pregnant women aged 35 years and over. From 1989 to 1991, 1208 women seen at the National University Hospital had karyotyping procedures performed for maternal age > 35 years as well as second trimester serum samples taken for alpha-fetoprotein and human chorionic gonadotrophin. Sixteen (1.3%) chromosomal abnormalities were present. Using cut off risk levels of 1:250 and 1:384, the sensitivity of the analysis in screening for Down's syndrome pregnancies was 71.5% and 86% respectively. For the non Down's chromosomal abnormalities, using cut off risk levels of 1:250 and 1:384, the sensitivity of the analysis was only 22.3% and 33.4% respectively. Thus risk calculations based on the two serum markers and maternal age failed to identify all fetuses with abnormal chromosomes.

Sex hormone-induced mammary carcinogenesis in female noble rats: the role of androgens

Breast cancer is the most common cancer and the second most frequent cause of cancer death in women. Despite extensive research, the precise mechanisms of breast carcinogenesis remain unclear. We have shown that in female rats, treatment with a combination of oestrogen and testosterone can induce a high incidence of mammary cancer. The dosage of testosterone affects only the latency period of mammary cancer, not the final incidence. Based on these observations, we hypothesize that oestrogen and androgens may act in concert on the mammary gland to induce mammary carcinogenesis, with oestrogen serving as the predominant initiator whereas the androgen acts as a major promoter. In the present study, we report the changes in morphology of the mammary gland with special emphasis on the perialveolar or interlobular stroma after treatment with various sex hormone protocols. Our data showed that after treatment with testosterone, either alone or in combination with 17beta-oestradiol, there was overexpression of the androgen receptor in alveolar or ductal epithelial cells. Concurrent with strong expression of the androgen receptor in epithelium, there was also an increase in the amount of perialveolar and interlobular connective tissue, a decrease in surrounding adipose tissue and an increase in proliferation rate of fibroblast-like cells in the stroma. All these changes were blocked by simultaneous implantation of flutamide, indicating that androgens play a crucial role in the process despite the absence of androgen receptors in stromal cells. We further measured the mammary gland density (MGD), in order to determine the ratio of fatty to non-fatty tissue. The data showed that MGD values were significantly higher in animals treated with testosterone alone or in combination with 17beta-oestradiol than in those treated with 17beta-oestradiol alone or in controls. Furthermore, treatment with different doses of testosterone resulted in an increase in MGD in a dose-dependent manner. These findings highlight the effect of androgens on the stroma, probably through a paracrine action of epithelial cells. The stroma may, in turn, promote mammary carcinogenesis in a reciprocal fashion.

Immortalization of human prostate epithelial cells by HPV 16 E6/E7 open reading frames

BACKGROUND

The exact pathogenesis for prostate cancer is not known. Progress made in prostate cancer research has been slow, largely due to the lack of suitable in vitro models. Here, we report our work on the immortalization of a human prostate epithelial cell line and show that it can be used as a model to study prostate tumorigenesis.

METHODS

Replication-defective retrovirus harboring the human papillomavirus (HPV) type 16 E6 and E7 open reading frames was used to infect primary human prostate epithelial cells. Polymerase chain reaction, followed by Southern hybridization for the HPV 16 E6/E7, Western blot for prostatic acid phosphatase, telomeric repeat amplification protocol assay for telomerase activity, two-dimensional gels for cytokeratins, and cytogenetic analysis were undertaken to characterized the infected cells.

RESULTS

The retrovirus-infected cell line, HPr-1, continued to grow in culture for more than 80 successive passages. Normal primary cells failed to proliferate after passage 6. HPr-1 cells bore close resemblance to normal primary prostate epithelial cells, both morphologically and biochemically. However, they possessed telomerase activity and proliferated indefinitely. Cytogenetic analysis of HPr-1 cells revealed a human male karyotype with clonal abnormalities and the appearance of multiple double minutes.

CONCLUSIONS

The HPr-1 cells expressed prostatic acid phosphatase and cytokeratins K8 and K18, proving that they were prostate epithelial cells. They were benign in nude mice tumor formation and soft agar colony formation assay. The HPr-1 cell line is an in vitro representation of early prostate neoplastic progression.

Induction of high incidence of mammary tumour in female Noble rats with a combination of 17beta-oestradiol and testosterone

Breast cancer is the most common cancer and the second most frequent cause of cancer death in women. Despite extensive research, the precise mechanisms of breast carcinogenesis remain unclear. One of the reasons for this is due, at least in part, to a lack of a suitable animal model which can closely mimic the breast carcinogenesis in normal situations without using chemical carcinogens. We have developed an animal model of mammary gland carcinogenesis using a combination of oestradiol and testosterone, and succeeded in inducing a high percentage of female Noble rats to develop mammary cancer in a relatively short time (approximately 6 months). The results showed that androgens might work as a promoter to shorten the latency time of mammary gland carcinogenesis. Histopathological examination revealed that hyperplasia and dysplasia were first observed 2 months after treatment, in situ carcinoma after 3 months, and fully developed carcinoma of various forms including cribriform, papillary and camedo types were observed from 5 to 6 months after hormone implantation. Animals implanted with oestrogen or testosterone alone also developed mammary cancers, though with a lower overall incidence than the two hormones combined. They ranged from well differentiated to poorly differentiated forms with predominantly infiltrating ductal carcinoma. We have also observed a case of secondary cancer in the uterus. In addition to the high incidence of carcinoma, there was also a peculiar unexplained ipsilateral correlation between the site of hormonal implantation and the location of tumours, and the highest incidence of carcinogenesis was found to be in thoracic mammary gland. The study showed that both oestrogens and androgens are important in mammary cancer development. The animal model would prove to be a useful model for analysis of the mechanism(s) of hormonal carcinogenesis.

Downregulation and abnormal expression of E-cadherin and beta-catenin in nasopharyngeal carcinoma: close association with advanced disease stage and lymph node metastasis

Nasopharyngeal carcinoma (NPC) is predominantly of the undifferentiated histological subtype. Histological differentiation is of limited prognostic significance in NPC. Recent studies have suggested that downregulation of the cadherin-catenin cell adhesion complex may play a crucial role in the initial stage of cancer invasion and metastasis and is associated with poor prognosis in human cancers. Expression of E-cadherin has not been reported previously in NPC, and its prognostic value in NPC is unknown. The purpose of this study was to examine the expression pattern of E-cadherin and its associated partner, beta-catenin, in NPC and their possible applications as prognostic markers to predict the clinical outcome of NPC. Expression of the E-cadherin and beta-catenin was examined by immunohistochemical methods in 74 cases of primary NPC and 17 of their corresponding lymph node metastases. Normal nasopharyngeal epithelium showed strong and homogeneous immunocytochemical staining of E-cadherin and beta-catenin at the cell membranes and intercellular junctions. In contrast, primary NPC showed variable and heterogeneous staining patterns of E-cadherin and beta-catenin. Loss of membranous E-cadherin expression was significantly associated with advanced stages of diseases (P<.001). Eighty percent to ninety percent of NPC in stages IV and V (Ho's staging), respectively, showed a reduced (<35%) membranous staining of E-cadherin compared with normal nasopharyngeal epithelium. Expression of beta-catenin also was downregulated in advanced NPC. Ninety percent to one hundred percent of NPC in stages IV and V (Ho's staging) expressed a reduction (<35%) of imnmunocytochemical staining of beta-catenin. The expression pattern of beta-catenin staining was strongly associated with the expression of E-cadherin (P<.001). Unlike E-cadherin, nuclear staining of beta-catenin expression was observed in some of the primary NPC and lymph node metastasis. Reduced expression of E-cadherin and beta-catenin expression was associated with a shorter survival of NPC patients (P<.001). In advanced NPC patients (stages IV and V), a significant difference in survival was observed in tumors with higher or lower levels of E-cadherin expression (P=.0224, log-rank test). These observations suggests that expression of E-cadherin and beta-catenin may have prognostic values in NPC patients.

Direct intrauterine fetal therapy in a case of bronchopulmonary sequestration associated with non-immune hydrops fetalis

Bronchopulmonary sequestration associated with non-immune hydrops fetalis is generally recognized as a uniformly fatal fetal condition without fetal surgical intervention. We describe here the first case of such a condition treated successfully with direct intrauterine fetal therapy using digoxin and frusemide.

Reversal of methotrexate resistance in human squamous carcinoma cells by SQM1-liposome

SQM1, a membrane protein associated with methotrexate (MTX) transport was incorporated into unilamellar vesicles, forming. SQM1-Liposome. Human squamous carcinoma of the head and neck (SqCHN) cells resistant to MTX with defective MTX transport and low SQM1 expression were treated with SQM1-Liposome. SQM1 content was found to be increased in these treated SqCHN cells by radioimmunoassay. Concurrent increases in MTX uptake and MTX cytotoxicity in these treated SqCHN cells were found. The ability to reverse MTX-resistance in vitro opens further possibilities for in vivo applications.

Enlargement of cisterna magna as an indicator of chromosomal abnormalities in a low-risk Asian population

AIMS

The aims of this study was to invent the prevalence of cisterna magna (CM) enlargement in a low-risk population and relate this to chromosomal abnormalities and initial delivery outcome.

STUDY DESIGN

11,145 patients having routine ultrasound scan at 21st week of pregnancy were screened for abnormalities. Cases with CM enlargement were traced and outcome retrieved either from case notes or from the patients.

RESULTS

In our low-risk population six fetuses were found to have CM enlargement. Only one had a chromosomal abnormality, 47XY + 18, and this fetus also presented with other malformations. Four were healthy at birth and one, also with other malformations, is showing signs of mental retardation. All cases were male.

CONCLUSION

Isolated CM enlargement does not seems to be an indicator for chromosomal abnormalities, especially if the fetus is a male. Still, it should alert the examiner of the possibility of other malformations, which may be of importance.

Pooling of contrast material on computed tomography mandates aggressive management of blunt hepatic injury

BACKGROUND

Nonoperative management of blunt hepatic injury is currently a widely accepted treatment modality. Computed tomography (CT) is an important imaging study both for diagnosis and follow-up of these patients. There is, however, no reliable predictor of failure of nonoperative treatment other than the ultimate development of hemodynamic instability. Previous reports mostly were based on the data obtained from low-speed dynamic incremental scanners. The purpose of this study is to evaluate the value of a high-speed helical scanner in predicting the outcome of patients managed nonoperatively.

METHODS

During a 30-month period, 194 patients with blunt hepatic injury were treated, 150 of them were hemodynamically stable after initial resuscitation and underwent abdominal CT examination. All CT scans were performed with the High Speed Advantage Scanner. The CT scans and medical records were reviewed.

RESULTS

Nonoperative management was successfully applied to all patients with grade I and II, 93% of grade III, 87% of grade IV, and 67% of grade V liver injuries. Twelve patients required liver-related celiotomy. Pooling of contrast material was detected on the CT scans of 8 patients. Six (75%) of these patients developed hemodynamic instability and required liver-related celiotomy later. Pooling of contrast material can be detected in 50% of the patients receiving liver-related celiotomy.

CONCLUSION

The presence of pooling of contrast material within the hepatic parenchyma indicates free extravasation of blood as a result of active bleeding. In patients with blunt hepatic injury, if this sign is detected, nonoperative treatment should be terminated and angiography or celiotomy undertaken promptly. With the increasing use of high-speed spiral CT scanner and improvement in scanning technique, pooling of contrast material may become a sensitive sign for active bleeding and may be used as a guide for the selection of treatment modality.

Abnormal origin of the vertebral artery from the common carotid artery

An abnormal origin of the vertebral artery from the common carotid artery (VA-CC) may occur on the right or left side with different embryonic mechanisms. We describe a patient with a double developmental anomaly, a right VA-CC and a right aortic arch. The rotation of the aortic arch caused a "twist" of the embryonic mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic mechanisms at first glance. We discuss the pivotal points in differentiating the embryonic mechanisms of VA-CC.

Periaortic hematoma on helical CT of the chest: a criterion for predicting blunt traumatic aortic rupture

OBJECTIVE

The purpose of this study was to evaluate the accuracy of helical CT of the chest for predicting blunt traumatic aortic ruptures when periaortic hematoma is used as a positive criterion.

CONCLUSION

We recommend the use of periaortic hematoma as a criterion for predicting traumatic aortic ruptures on CT because this criterion is sensitive and can reduce the false-positive rate of CT interpretations.

Characterization of glycoconjugates of guinea pig seminal vesicle by lectin histochemistry

In the present study, the expression of glycoconjugates in the guinea pig seminal vesicle was localized and partially characterized by lectin histochemistry using a battery of 30 different lectins specific for different carbohydrate residues. The results indicate that the glandular epithelium of the guinea pig seminal vesicle exhibits complex glycoconjugates rich in Man, beta-GlcNAc, beta-Gal, alpha/beta-GalNAc, Fuc and complex NeuAc(alpha2,6)Gal/GalNAc residues, as shown by its positive reactions to most lectins used. The Golgi region of the luminal secretory epithelial cells expresses a complex glycoconjugate pattern, as shown by its strong reactions to Man-(PSA, GNA), beta-GlcNAc-(S-WGA, PWA, DSA, UDA), beta-Gal-(RCA-I and -II), alpha/beta-GalNAc-(SBA, Jac, VVA, BPA) and complex NeuAc-(SNA) specific lectins, indicating that the secretory epithelial cells are active in glycosylation and secretion process. It was also shown in the present study that the basal and luminal epithelial cells are different in their glycoconjugates. The basal epithelial cells are rich in NeuAc(alpha2,3)Gal residues as they are stained specifically by MAA. The fibroblasts in the epithelial-smooth muscle interface and the smooth muscle cells close to the glandular epithelium are shown to express more glycoconjugates as they are stained intensely by GS-I-B4, GS-II and SBA. However, their role in the epithelial-stromal interaction in the seminal vesicle remains to be elucidated. In summary, the present study reports for the first time on the lectin binding patterns of the guinea pig seminal vesicle, and the results show that the seminal vesicle epithelium elaborates and secretes glycoconjugates in a complex pattern. Some of the lectins might be useful as histochemical markers for the secretory activity and specific structural components in the guinea pig seminal vesicle.

Sex hormone-induced prostatic carcinogenesis in the noble rat: the role of insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor (VEGF) in the development of prostate cancer

BACKGROUND

Despite extensive effort, the mechanisms of prostate carcinogenesis are still unknown. We report on a modified method which enabled us to induce a high incidence of prostate carcinogenesis in the Noble rat and examined the role of insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) and their receptors during sex hormone-induced prostate carcinogenesis.

METHODS

Noble rats were implanted subcutaneously with a combination of testosterone and estradiol capsules for up to 12 months. Animals were sacrificed starting at 2 months after implantation, and the prostate gland was removed for histopathological and immunohistochemical studies.

RESULTS

The results showed that hyperplasia/dysplasia was detected as early as 2 months after treatment, while carcinoma in situ was induced in 4 months and adenocarcinoma in 7 months. Our data suggest that IGF-1, produced by stromal cells in hyperplasia, exerted its effects, through a paracrine mode, on epithelial cells which were IGF-1 receptor (IGF-1R)-positive. The production of IGF-1 appeared to switch to epithelial cells in adenocarcinoma, through which it regulated tumor cell growth via autocrine mode by binding to IGF-1R of carcinoma cells. On the other hand, VEGF was overexpressed in hyperplastic/dysplastic and carcinoma cells, while VEGF-R was detected in endothelial cells. The results suggest that overexpression of VEGF in deranged epithelia and arterial muscle cells may exert its influence on stromal angiogenesis and abnormal growth of prostate gland.

CONCLUSIONS

A modified Noble rat model with a high incidence of prostate carcinogenesis has been developed. Using this model, we have further established that IGF-1 and VEGF may be the critical regulators in mediating epithelial-stromal interactions in sex hormone-induced prostate carcinogenesis.

Hypoplasia of the internal carotid artery with intercavernous anastomosis

We report a symptomatic case of unilateral hypoplasia of the internal carotid artery with an intercavernous anastomosis, a very rare developmental anomaly. The symptoms were caused by occlusion of the proximal middle cerebral artery which possibly related to the haemodynamic stress caused by the anomalous intercavernous anastomosis.

Early fetal blood sampling--another available option for early prenatal diagnosis

Fourteen cases had early fetal blood sampling (FBS) performed between 13 and 18 weeks gestation in the Antenatal Diagnostic Centre, National University Hospital, Singapore from Jan 1988 to December 1994. The indications were: a) ultrasound abnormality (n = 6), b) hydrops (n = 1), c) screening for blood disorders (n = 2), d) amnio results inconclusive or to confirm abnormal amnio results (n = 5). This article analyses retrospectively the early FBS procedure and its outcome. There were no procedure related fetal losses in this study. The reliable rapid results obtained following the procedure enabled the obstetrician to counsel the couple regarding the current pregnancy and advise them accordingly for the subsequent pregnancy. Thus we found it useful not only in our patients but also for patients from overseas who get their results within a week to plan their stay.