Mitochondrial DNA mutations in chemical carcinogen-induced rat bladder and human bladder cancer

Mitochondrial (mt) DNA mutations have been described recently in different tumors, whereas similar studies focusing on bladder cancer are scarce. In an effort to understand the significance of mtDNA mutations in bladder cancer, we investigated the mtDNA alterations in both clinical human bladder cancer and in a carcinogen-induced rat bladder cancer model. Human bladder cancer tissues were obtained by radical cystectomy and transurethral resection of bladder tumors. Rat bladder tumors were induced in SD rats by treatment with N-butyl-N-(4-hydroxybutyl) nitrosamine in drinking water for 24-28 weeks. Genomic DNA was extracted from tumor specimens and microdissected normal bladder mucosae. Mitochondrial genes and D-loop region were amplified by PCR. The amplified PCR fragments were either cloned into plasmid vector or used for direct DNA sequencing. The results of DNA sequence revealed numerous point mutations in the non-coding D-loop region and different mtDNA genes in both human and rat bladder cancers. In addition, we also detected deletions of variable lengths in mononucleotide repeats in the D-loop region, ND2, ATPase 8 and COIII genes in human bladder cancer samples. Our results show that mtDNA exhibits a high rate of mutations in both human and rat bladder cancers. We also demonstrate that the repetitive sequences of mononucleotides within the mt genome are unstable and subjected to deletions. The high incidence of mtDNA mutations in bladder cancer suggests that mtDNA and mitochondria could play an important role in the process of carcinogenesis and also mtDNA could be valuable as a marker for early bladder cancer diagnosis.

Intrapartum Cesarean Delivery After Successful External Cephalic Version

OBJECTIVE

We sought to estimate whether the risk of intrapartum cesarean delivery is higher in pregnancies after successful external cephalic version.

DATA SOURCES

We searched the MEDLINE, PubMed, EMBASE, and Cochrane Library databases to identify relevant studies. Abstracts of the American College of Obstetricians and Gynecologists Annual Clinical Meeting and the Society for Maternal-Fetal Medicine Annual Meeting were searched by hand.

STUDY SELECTION

Studies published between 1980 and 2002 that provided data allowing us to estimate the cesarean rate in both pregnancies after successful version and spontaneous cephalic-presenting pregnancies were selected.

TABULATION, INTEGRATION, AND RESULTS

Relative risks (RRs) and 95% confidence intervals (CIs) between the 2 compared groups were calculated. We used a meta-analysis to assess the heterogeneity of the studies and to combine the results from the included studies. Six eligible studies were identified. The cesarean rate was 27.6% in pregnancies after successful version and 12.5% in cephalic-presenting pregnancies. The combined RR and 95% CI was 2.04 (1.43-2.91). The increased cesarean rate in pregnancies after successful version was accounted for primarily by a higher incidence of emergency cesarean delivery for dystocia and fetal distress; the RR (95% CI) for these 2 events was 2.19 (1.38-3.48) and 2.10 (1.18-3.75), respectively.

CONCLUSION

The intrapartum cesarean delivery rate after successful version is 2 times that in pregnancies where there is spontaneous cephalic presentation. Pregnancies after successful version should not be considered the same as a normal pregnancy.

Roller Compaction of Crude Plant Material: Influence of Process Variables, Polyvinylpyrrolidone, and Co‐milling

Roller compaction of a milled botanical (Baphicacanthus cusia) with and without a binder, polyvinylpyrrolidone (PVP) was conducted. Effects of co-milling on binder function and flowability of the powder blend was also investigated. Flakes were comminuted, and the size and size distribution, friability, Hausner ratio, and Carr index of the granulations were determined. Crude herb should be reduced to a suitable size for it to be successfully roller compacted. Larger-sized and less friable granules were obtained with decreasing roller speed. Addition of PVP affected the flowability and binding capacity of the herbal powder blend, which influenced size and friability of the granules. Co-milling of PVP with the herbal powder enhanced the flow of the blends and the effectiveness of the binder, which contributed favorably to the roller-compacted product. Roller compaction is a convenient and cost-effective granulating technique suitable for milled botanicals. Co-milling can be used to improve the properties of roller-compacted products.

Prediction of differential creatinine clearance in chronically obstructed kidneys by non-contrast helical computerized tomography

PURPOSE

We investigate the use of non-contrast helical computerized tomography (NCHCT) in the measurement of differential renal parenchymal volume as a surrogate for differential creatinine clearance (CrCl) for unilateral chronically obstructed kidney.

MATERIALS AND METHODS

Patients with unilateral chronically obstructed kidneys with normal contralateral kidneys were enrolled. Ultrasonography (USG) of the kidneys was first done with the cortical thickness of the site with the most renal substance in the upper pole, mid-kidney, and lower pole of both kidneys were measured, and the mean cortical thickness of each kidney was calculated. NCHCT was subsequently performed for each patient. The CT images were individually reviewed with the area of renal parenchyma measured for each kidney. Then the volume of the slices was summated to give the renal parenchymal volume of both the obstructed and normal kidneys. Finally, a percutaneous nephrostomy (PCN) was inserted to the obstructed kidney, and CrCl of both the obstructed kidney (PCN urine) and the normal side (voided urine) were measured two 2 after the relief of obstruction.

RESULTS

From March 1999 to February 2001, thirty patients were enrolled into the study. Ninety percent of them had ureteral calculi. The differential CrCl of the obstructed kidney (%CrCl) was defined as the percentage of CrCl of the obstructed kidney as of the total CrCl, measured 2 weeks after relief of obstruction. The differential renal parenchymal volume of the obstructed kidney (%CTvol) was the percentage of renal parenchymal volume as of the total parenchymal volume. The differential USG cortical thickness of the obstructed kidney (%USGcort) was the percentage of mean cortical thickness as of the total mean cortical thickness. The Pearson's correlation coefficient (r) between %CTvol and %CrCl and that between %USGcort and %CrCl were 0.756 and 0.543 respectively. The regression line was %CrCl = (1.00) x %CTvol - 14.27. The %CTvol overestimated the differential creatinine clearance by about 14%, but the correlation is good.

CONCLUSION

The differential renal parenchymal volume measured by NCHCT provided a reasonable prediction of differential creatinine clearance in chronically obstructed kidneys.

One-year urodynamic outcome and quality of life in patients with concomitant tension-free vaginal tape during pelvic floor reconstruction surgery for genitourinary prolapse and urodynamic stress incontinence

The aim of the study was to examine the 1-year urodynamic outcome and quality of life in patients who have had concomitant tension-free vaginal tape insertion during pelvic floor reconstruction surgery. The medical notes of a retrospective cohort of 45 patients who had undergone tension-free vaginal tape together with pelvic floor reconstruction surgery were reviewed. The operative information, the results of the urodynamic studies and the change in the quality-of-life scores 1 year after surgery were examined. The quality of life was assessed with both general and disease-specific quality-of-life questionnaires (General Health Questionnaire (GHQ-12), Urogenital Distress Inventory (UDI-6), Incontinence Impact Questionnaire (IIQ-7)). Patient satisfaction was assessed with the validated Chinese version of the Client Satisfaction Questionnaire (CSQ). Forty-five patients underwent tension-free vaginal tape insertion together with pelvic floor reconstruction surgery. The overall objective cure rate was 43%. There was a significant improvement in the disease specific quality-of-life assessment (UDI-6 score 38.3-15.5; P<0.01) and (IIQ-7 score 15.0-4.0; P<0.01). The patients who had a concomitant cystocele repair had a worse objective cure rate than patients without concomitant cystocele repair (38% vs 67%; P=0.19).

Use of a Fluidized Bed Hammer Mill for Size Reduction and Classification: Effects of Process Variables and Starting Materials on the Particle Size Distribution of Milled Lactose Batches

The process capability of a fluidized bed hammer mill was investigated with respect to four process variables, namely, rotational speeds of beater system and classifier wheel, airflow rates and length of grinding zones, as well as the particle size and flow property of the starting materials. The size distributions of all the milled lactose batches could be fitted to the Rosin Rammler distribution (RRD) function. The characteristic particle size (De) and uniform coefficient (n), which were derived from the RRD function, complemented the size at the 99th percentile of the cumulative undersize distribution (D99) to characterize the lactose batches. Lower De and D99 values indicate a finer powder while a higher n value indicates a narrower size distribution. The beater speed played a critical role. Increasing the beater speed from 12000 to 21000 rpm generally resulted in an increase in n and a decrease in D99 values due to the greater amount of milling energy supplied. The particle size and flow property of the starting material also played an important role at beater speed of 12000 rpm, where the lowest amount of milling energy was supplied. When a higher amount of milling energy was provided, the effect of particle size of the starting material was less significant. The other process variables exerted varying effects. Increasing the classifier wheel speed from 5000 to 15000 rpm decreased the De and D99 and increased the n values of the milled lactose batches, provided sufficient milling energy was supplied to the lactose particles. Changing airflow rates from 80 to 90 m3/h generally resulted in larger De and D99 values and lower n values as the higher airflow rate provided greater airflow-induced kinetic energy that facilitated the passage of lactose through the classifier wheel. However, changing the long grinding zone to a short one did not significantly affect the De, D99 and n values of the milled lactose batches produced. Small lactose particles of narrow size distribution could be obtained using the fluidized bed hammer mill upon gaining a better understanding of the milling process.

Influence of storage conditions and type of plasticizers on ethylcellulose and acrylate films formed from aqueous dispersions

PURPOSE

To investigate the influence of storage conditions and types of plasticizers on the properties and stability of ethylcellulose and polymethacrylate films and to elucidate the mechanism for the changes observed.

METHODS

Films were prepared from Surelease, Aquacoat and Eudragit L 30D dispersions by the casting method. The effects of different plasticizers on the morphology, transparency, mechanical property and water vapour permeability of the prepared films were studied. The film samples were exposed to storage conditions of 30 degrees C and 50 or 75 %RH. Samples were removed at pre-determined time intervals for mechanical testing and analysis of plasticizer content in the films.

RESULTS

It was found that films prepared from aqueous ethylcellulose dispersions were relatively weaker and more brittle than acrylate films. Acrylate films did not show any significant change in mechanical property when stored at high humidity. However, the properties of ethylcellulose films stored at high humidity varied depending on the type of plasticizers present.

CONCLUSIONS

The changes in mechanical property of ethylcellulose films on storage were mainly attributed to the loss of plasticizers during storage, causing further coalescence of ethylcellulose films and to a smaller extent, reduction in moisture content of the film.

Formation of alginate microspheres produced using emulsification technique

This study investigated the formative process of alginate microspheres produced using an emulsification technique. The alginate microspheres were produced by cross-linking alginate globules dispersed in a continuous organic phase using various calcium salts: calcium chloride, calcium acetate, calcium lactate and calcium gluconate. The size, shape, drug content and Ca2+ content of the microspheres were evaluated. The tack, viscosity and pH of the calcium salt solution and percentage of Ca2+ partitioned into the organic phase were determined. Microscopic examination of the test emulsion at various stages of the emulsification process was also carried out. The propensity of cross-linking reaction was found to be dependent on successful collision between alginate and calcium salt globules. Examination of the characteristics of microspheres indicated that the formed microsphere was a resultant product of alginate globule clustering. The growth propensity of microspheres was promoted by the higher rate and extent of cross-linkage which was governed by the pH, tack and/or Ca2+ content of the cross-linking solution, as well as the dissociation constant and diffusivity of the calcium salt. Overall, the amount of free Ca2+ cross-linked with alginate in the formed microspheres was in the following order: calcium acetate > calcium chloride + calcium acetate > calcium chloride + calcium gluconate; calcium chloride + calcium lactate > calcium chloride. In microencapsulation by emulsification, the mean size of the microspheres produced can be modified by varying the tack, pH and Ca2+ content of the cross-linking solution and through the use of a combination of calcium salts. The shape of the microspheres produced was, nonetheless, unaffected by the physicochemical properties of the cross-linking solution.

Ultrafine grinding using a fluidized bed opposed jet mill: effects of feed load and rotational speed of classifier wheel on particle shape

Circularity, aspect ratio, modelx, and pellips were employed to study the effects of process parameters, namely varying feed loads and rotational speeds of the classifier wheel, of the fluidized bed opposed jet mill on the shape of the micronized particles produced. The Shapiro-Wilk statistical test showed that 80.0% of the shape distributions of the four descriptors were not normal. Therefore, the Kruskal-Wallis test, which is a nonparametric statistical test, was employed to analyze the data. Micronized particles were more spherical and less elongated, as indicated respectively by higher median circularity and lower median modelx values when compared to unmilled lactose. These descriptors were able to indicate that the particles had been micronized. When feed loads of 250 and 350 g were used, increasing the rotational speed of the classifier wheel was found to bring about a decrease in span values of all the shape descriptors, indicating that the micronized particles were more uniform in shape. Micronized particles produced had lower median aspect ratio values than the unmilled lactose, whereas a higher feed load of 450 g resulted in the production of micronized particles that were less uniform in shape and more elliptical in nature, as reflected by the lower median pellips values. A higher feed load of 450 g caused a high level of impingement of particles on to the rotating classifier wheel, causing decreased classifier wheel efficiency, and this resulted in a less well-controlled micronization process. Thus, aspect ratio and pellips were sensitive to the changes in performance of the classifier wheel. The four shape descriptors were proposed to be used collectively as indicators for the monitoring of the micronization process.

Release characteristics of pectin microspheres prepared by an emulsification technique

The potential application of pectin as a matrix polymer for making microspheres by an emulsification technique was explored, and the drug release property of these pectinate microspheres containing drug cores of varying aqueous solubilities: sulphanilamide, sulphaguanidine and sulphathiazole, was investigated using different dissolution media. The size and size distribution, specific surface area, drug content and drug release property of the pectinate microspheres were determined. The solubility and solution pH of drugs and their propensity to interact with pectin were characterized. Pectinate microspheres were successfully prepared by external gelation, using a modified emulsification technique. The kinetics of drug release from the microspheres best fitted Higuchi's model. Interestingly, the lowest percentage of drug released was produced by microspheres which were smallest in size and, therefore, largest in specific surface area, and containing sulphanilamide, the most aqueous soluble and the lowest molecular weight drug. Mathematical correlation study indicated that the drug release profile of pectinate microspheres was notably affected by the drug content and the extent of drug-pectin interaction in the microspheres. Generally, a higher percentage of drug was released from the microspheres with a higher drug content and/or lower extent of drug-pectin interaction. The extent of drug-pectin interaction was highest in microspheres containing sulphanilamide, followed by sulphaguanidine and sulphathiazole, opposite to that of drug content.

Risk and prediction of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin before 34 weeks

OBJECTIVE

To assess the timing and risk factors of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin (APHUO) before 34 weeks of gestation, and to formulate a clinical management protocol.

METHODS

A retrospective study involving singleton pregnancies with APHUO occurring before the 34th week of gestation was performed over a 4-year period at a university teaching hospital.

RESULTS

Seventy-five cases were identified. Fifty-nine (78.7%) did not have any associated uterine contractions, 74.7 and 90.7% of the cases were classified as having mild bleeding according to history and physical examination, respectively. The number of cases delivering before 37 weeks of gestation and before 34 weeks were 28 (37.3%) and 22 (29.3%), respectively. Eighteen cases (24%) delivered within the first week of APHUO, and 4 (5.3%) within the first day. The number of cases delivering within the first week was significantly higher when there were uterine contractions (62.5 vs. 13.6%, p < 0.001). The severity of bleeding was not shown to be related to the time of delivery.

CONCLUSION

APHUO that occurs before 34 weeks is associated with a high risk of preterm delivery before 34 weeks (29.3%). The chance of delivery within the first week is 62.5% when there are coexisting uterine contractions. Even if contractions are absent, the risk is still high (13.6%) and persists beyond the first week. We suggest that this group of patients should be managed with a course of steroid injection and hospitalization for 4 days.

Detection of mRNA expression of gonadotropin-releasing hormone and its receptor in normal and neoplastic rat prostates

Hypothalamic gonadotropin-releasing hormone (GnRH) plays a central role in the regulation of the mammalian reproductive systems as a releasing hormone of pituitary gonadotropins. However, a number of studies have shown that GnRH or its receptor are also expressed in some reproductive organs including prostate gland, mammary gland, ovary and placenta, tumors and tumor cell lines derived from these organs, suggesting that this peptide hormone may have other extrapituitary functions in addition to its role as a gonadotropin-releasing hormone. Moreover, it has been demonstrated that GnRH analogs exert some direct inhibitory effects on the proliferation of human and rat prostate cancer cells, probably mediated by its own specific receptors expressed in these tumor cells. In the present study, we investigated the mRNA expression of GnRH and its receptor in normal Noble rat prostate gland, and in three rat models of prostate cancer including the sex hormone-induced Noble rat model, an androgen-independent Noble rat prostatic tumor (AIT) and Dunning rat prostatic adenocarcinomas by RT-PCR and Southern blot analyses. The results showed that GnRH mRNA was expressed in the normal, hormone-treated and neoplastic rat prostates, in addition to its positive control expression in the hypothalamus, whereas its receptor was only detected in the androgen-dependent Dunning R3327H tumor. The detection of both GnRH and its receptor in the androgen-dependent Dunning R3327H tumor tissue suggests that this peptide hormone may have some autocrine and paracrine regulatory functions in this tumor. However, the gene expression of GnRH receptor was not detected in two androgen-independent Dunning tumor sublines and the Noble rat prostatic tumor, AIT, suggesting that the expression of GnRH receptor is lost or down-regulated in the prostatic tumors during the progression to a hormone-independent phenotype.

Investigation of the influence of mean HPMC particle size and number of polymer particles on the release of aspirin from swellable hydrophilic matrix tablets

The effects of hydroxypropyl methylcellulose (HPMC) of different particle size ranges, size distributions and concentrations on the release behaviour of aspirin from a swellable matrix tablet system were studied. A mean HPMC (Methocel K15M Premium) particle size of 113 microm was identified as a critical threshold in this study. Drug release rate increased markedly when polymer particle size was increased above 113 microm. Release rate was much less sensitive to changes in particle size below 113 microm. Aspirin release mechanism followed first order kinetics where mean HPMC particle size was below 113 microm. Release mechanism deviated from first order kinetics when the mean particle size was above 113 microm. Polymer fractions with similar mean particle size but differing size distribution were also observed to influence drug release rate but not release mechanism. First order release constant K(1) was found to be quantitatively related to the reciprocal of the cube root of both mean polymer particle size and number of polymer particles in the matrix.

Weight groupings in second order training methods for recurrent networks

In this paper, we use block-diagonal matrix of approximate the Hessian matrix in the Levenberg Marquardt method during the training of recurrent neural networks. We analyze the weight updating strategies and the groupings of the weights associated with the approximation. Two weight updating strategies, namely asynchronous and synchronous updating methods are investigated. Asynchronous method updated weights of one block at a time while synchronous method updates all weights at the same time. Variations of these two methods, which involve the determination of two parameters mu and lambda, are examined. Four weight grouping methods, correlation blocks, k-unit blocks, layer blocks and arbitrary blocks are investigated and compared. Their computational complexity, approximation ability, and training time is analyzed. Comparing with the original Levenberg Marquardt method, the block-diagonal approximation methods give substantial improvement in training time without degrading the generalization ability.

Analyzing holistic parsers: implications for robust parsing and systematicity

Holistic parsers offer a viable alternative to traditional algorithmic parsers. They have good generalization performance and are robust inherently. In a holistic parser, parsing is achieved by mapping the connectionist representation of the input sentence to the connectionist representation of the target parse tree directly. Little prior knowledge of the underlying parsing mechanism thus needs to be assumed. However, it also makes holistic parsing difficult to understand. In this article, an analysis is presented for studying the operations of the confluent preorder parser (CPP). In the analysis, the CPP is viewed as a dynamical system, and holistic parsing is perceived as a sequence of state transitions through its state-space. The seemingly one-shot parsing mechanism can thus be elucidated as a step-by-step inference process, with the intermediate parsing decisions being reflected by the states visited during parsing. The study serves two purposes. First, it improves our understanding of how grammatical errors are corrected by the CPP. The occurrence of an error in a sentence will cause the CPP to deviate from the normal track that is followed when the original sentence is parsed. But as the remaining terminals are read, the two trajectories will gradually converge until finally the correct parse tree is produced. Second, it reveals that having systematic parse tree representations alone cannot guarantee good generalization performance in holistic parsing. More important, they need to be distributed in certain useful locations of the representational space. Sentences with similar trailing terminals should have their corresponding parse tree representations mapped to nearby locations in the representational space. The study provides concrete evidence that encoding the linearized parse trees as obtained via preorder traversal can satisfy such a requirement.

A pruning method for the recursive least squared algorithm

The recursive least squared (RLS) algorithm is an effective online training method for neural networks. However, its conjunctions with weight decay and pruning have not been well studied. This paper elucidates how generalization ability can be improved by selecting an appropriate initial value of the error covariance matrix in the RLS algorithm. Moreover, how the pruning of neural networks can be benefited by using the final value of the error covariance matrix will also be investigated. Our study found that the RLS algorithm is implicitly a weight decay method, where the weight decay effect is controlled by the initial value of the error covariance matrix; and that the inverse of the error covariance matrix is approximately equal to the Hessian matrix of the network being trained. We propose that neural networks are first trained by the RLS algorithm and then some unimportant weights are removed based on the approximate Hessian matrix. Simulation results show that our approach is an effective training and pruning method for neural networks.

An improved method for the measurement of colour uniformity in pellet coating

Sucrose pellets in the size range of 0.71--0.85 mm were film-coated in a bottom-spray Wurster fluidised bed coater with a colour coating suspension of 7.5% w/w solids. Hydroxypropyl methylcellulose was used as a film former, polyethylene glycol as a plasticiser and yellow iron oxide as a coloured pigment. The colour distribution on the film coat was analysed using a tristimulus colorimeter and the colour value was measured in CIELAB units. Uniformity in the colour coat was indicated by the standard deviation of the colour measurement values. Four different methods for measuring the colour distribution over the colour coated pellets' surfaces were carried out. In method I, colour measurements of the pellets' surfaces were made by placing the pellets directly on the stage of the tristimulus colorimeter. A specially designed pellet sample holder was employed to assist the collection of colour measurements in methods II--IV. Colour measurements from eight spots on each pellet were taken in methods I, II and IV while method III involved measuring 24 spots per pellet. A total of eight overlapping spot measurements were taken in method IV while the eight spot measurements in method II were non-overlapping. Method II was found to be the most efficient, accurate and sensitive method for the measurement of spot colour distribution on pellets.

Microencapsulation of oils using sodium alginate

The feasibility of encapsulating wheatgerm oil and evening primrose oil using sodium alginate by the emulsification method was explored in this study. It is based on the chemical reaction between the water-soluble sodium alginate and polyvalent cation, calcium, to form the water-insoluble alginate. The factors investigated were the physical appearance of the microspheres, the amount of oil that could be encapsulated, the flow property, size distribution and mean size of the microspheres produced. Encapsulation efficiency and oil content of wheatgerm oil increased with an increase in oil load. The mean size of the microspheres increased sharply at a high oil load of 250% w/w. Photographs of microspheres taken showed that the microspheres were larger, spherical and had more vesicles within, as oil load increased. Encapsulation efficiency of evening primrose oil microspheres was similar to wheatgerm oil microspheres at the respective oil loads of 50, 250 and 350% w/w. The emulsification method developed was successfully applied to wheatgerm oil, a fixed oil, with a maximum encapsulation efficiency of approximately 88%. It was satisfactory for evening primrose oil, which also belongs to the family of fixed oils.

Study of the melt pelletization process focusing on the micromeritic property of pellets

Melt pelletization of lactose 450 M was carried out in an 8-l high shear mixer using PEG 3000 as the meltable binder. The pore size and size distribution of the melt pellets were determined using mercury intrusion porosimetry. The pore size distribution of melt pellets was found to be bimodal. With a higher binder concentration, post-melt impeller speed or longer post-melt processing time, the fraction of large pores in the agglomerates was reduced but the tendency of the agglomerates to develop sub-micron pores increased. The extent of formation of large pores was dependent on the interplay between the inter-particle distance of lactose particles and the contraction property of molten binder. High process temperature was associated with a greater amount of water loss from the melt agglomerates. The water vapor liberated from the lactose particles, was trapped in the molten PEG during the pelletization process. The formation of sub-micron pores was a result of escape of this water vapor on solidification of the molten PEG as well as agglomerate densification. The quantity of sub-micron pores produced was found to be related to the level of water loss. The melt agglomeration gave rise to large agglomerates when long post-melt processing time, high post-melt impeller speed or binder concentration was used.

Effect of tabletting compaction pressure on alginate microspheres

Alginate and alginate-hydroxypropylmethylcellulose (HPMC) microspheres were prepared by the emulsification method. The compaction of microspheres for producing tablet dosage forms raises concerns about possible damage to microsphere walls with subsequent unpredictable dissolution rates. The effect of different compaction pressures on the integrity of the microspheres was investigated. The addition of a diluent, microcrystalline cellulose (MCC), was required to make compacts containing alginate and alginate-HPMC microspheres. Compacts containing alginate-HPMC (7:3) microspheres had the highest crushing strength followed by compacts containing alginate-HPMC (9:1) microspheres and alginate microspheres. However, compact crushing strength did not vary significantly with increased compaction pressures over the range of compaction pressures investigated. Differences in the drug release profiles of the original non-compacted and compacted alginate and alginate-HPMC microspheres were slight and not marked. Although dentation and distortion of the microspheres were observed with increasing compaction pressures, the microspheres generally remained intact, with minimal rupture/fracture.

Quantification of the surface morphologies of lactose carriers and their effect on the in vitro deposition of salbutamol sulphate

Application of the scanning probe microscopy technique for quantitative measurement of the surface roughness of lactose carriers was evaluated. The roughness values of four different lactose carriers were related to the in vitro deposition results of the drug, salbutamol sulphate. The rugosity values of the lactose carriers were represented by Ra values which were in the order of DCL-40>DCL-11>lactose 325M>lactose 200 M. In vitro deposition results using a twin impinger showed that rougher carrier surfaces generally allowed more drug particles to be emitted from the capsules and inhaler but the availability of the drug to stage 2 was reduced, as detachment of drug particles from the carrier surfaces was more hindered. There was an optimum Ra value for greater delivery of the drug particles to stage 2 of the twin impinger. A balance between adherence and detachment of the drug from the carrier surface was needed in order to optimize the delivery of a drug to the desired target sites using a dry powder inhaler.

Influence of production variables on the sphericity of melt pellets

This paper reports the influence of post-melt impeller speed, post-melt processing time, binder concentration and particle size of bulk material on the sphericity of pellets produced by melt pelletization in a high shear mixer. Lactose was used as the bulk material with polyethylene glycol 3000 as a meltable binder. The sphericity of pellets was found to be affected by post-melt impeller speed and post-melt processing time. Binder concentration and particle size of bulk material had a lesser effect on pellet sphericity. The melt pelletization process can be divided into two spheronization phases (a fast initial rate, followed by a slower rate). The change in the spheronization rate was associated with the pellet size, porosity and flow pattern of the processing material. The present study established a bi-exponential mathematical model to relate the pellet sphericity with post-melt specific energy consumption. The relationship of pellet sphericity with post-melt specific energy consumption was independent of the effects of the production variables.

Interaction of p-hydroxybenzoic esters with beta-cyclodextrin

In the present investigation, the complex formation of beta-cyclodextrin (betaCD) with p-hydroxybenzoic esters (parabens) was studied by mixing betaCD with methyl, ethyl, propyl and butyl parabens, respectively, in aqueous solutions and subjecting the resultant mixtures individually to the following processes: occasional shaking for 24 h at 25 degrees C, continuous shaking using shaker bath for 24 h at 25 degrees C, intermittent ultrasonification for 90 min at 25 degrees C, autoclaving at 115 degrees C for 30 min and freeze-drying followed by reconstitution with distilled water. The degrees of interaction between betaCD and the parabens subjected to the various processes were evaluated, using the membrane dialysis method. The difference in the method of processing did not affect the degree of interaction significantly. However, the degree of interaction was found to increase proportionally with the concentration of betaCD. The alkyl group of the parabens was also found to affect the extent of interaction. Compared to methyl paraben, the degree of interaction of ethyl paraben was observed to be lower. Interestingly, further increase in the size of the alkyl group significantly enhanced the extent of interaction. Studies using 1H-NMR showed that the extent of interaction depended on how well the parabens could fit into the betaCD cavity.

Hemorrhagic pyelitis, ureteritis, and cystitis secondary to cyclophosphamide: case report and review of the literature

OBJECTIVE

Hemorrhagic cystitis is a well-known complication of cyclophosphamide therapy but extensive involvement of the entire urinary tract is far less common. We report here a patient who developed severe hemorrhagic pyelitis, ureteritis, and cystitis after one cycle of cyclophosphamide-containing combination chemotherapy.

METHOD

A patient with synchronous carcinoma of the ovary and the uterus developed severe hemorrhagic pyelitis, ureteritis, and cystitis leading to bilateral hydronephroses and acute renal failure after one cycle of combination chemotherapy containing cyclophosphamide. The blood clots in the upper urinary tract were aspirated endoscopically and bilateral internal ureteric stents were inserted.

RESULT

She underwent a prolonged diuretic phase with several episodes of hypokalemia, hypomagnesemia, and hypocalcemia and required intensive fluid and electrolytes replacement. Subsequently, she recovered fully with the ureteric stents removed 26 days later.

CONCLUSION

In contrast to previous reports, where 2.8 g of cyclophosphamide was estimated to be the minimum cumulative dose required to cause hemorrhagic cystitis, this case illustrates that severe hemorrhagic complication can occur even after a low dose of cyclophosphamide (600 mg/m(2), total dose of 846 mg). Prompt diagnosis and intervention may be life-saving.

How to design a connectionist holistic parser

Connectionist holistic parsing offers a viable and attractive alternative to traditional algorithmic parsers. With exposure to a limited subset of grammatical sentences and their corresponding parse trees only, a holistic parser is capable of learning inductively the grammatical regularity underlying the training examples that affects the parsing process. In the past, various connectionist parsers have been proposed. Each approach had its own unique characteristics, and yet some techniques were shared in common. In this article, various dimensions underlying the design of a holistic parser are explored, including the methods to encode sentences and parse trees, whether a sentence and its corresponding parse tree share the same representation, the use of confluent inference, and the inclusion of phrases in the training set. Different combinations of these design factors give rise to different holistic parsers. In succeeding discussions, we scrutinize these design techniques and compare the performances of a few parsers on language parsing, including the confluent preorder parser, the backpropagation parsing network, the XERIC parser of Berg (1992), the modular connectionist parser of Sharkey and Sharkey (1992), Reilly's (1992) model, and their derivatives. Experiments are performed to evaluate their generalization capability and robustness. The results reveal a number of issues essential for building an effective holistic parser.

In situ hybridization study of PSP94 (prostatic secretory protein of 94 amino acids) expression in human prostates

BACKGROUND

The prostatic secretory protein of 94 amino acids (PSP94), also named beta-microseminoprotein, is one of the major proteins secreted by the human prostate. However, its value as a prognostic marker for prostate cancers is still under debate. The aim of the present study was to examine the expression pattern of this protein in fetal, pubertal, and aged human prostates.

METHODS

Nonisotopic in situ hybridization using a digoxigenin-labeled riboprobe for PSP94 and immunohistochemistry were used to demonstrate the expression of PSP94 in different regions or zones of fetal, pubertal, and adult human prostates. Its localization pattern was also compared with those of two other major secretory proteins, prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), by immunohistochemistry.

RESULTS

PSP94 mRNA and its protein were localized to the secretory epithelium of normal pubertal and adult human prostates. No hybridization signal and immunoreactivity of PSP94 were seen in fetal prostates at 6-7 months of gestation, whereas some glandular cells were positive to PSA and PAP immunostainings. In the adult prostates, PSP94 expression was intense in the acini in the peripheral zone, less intense in the transition zone, and variable in the central zone. Such a zonal expression pattern was more apparent in the pubertal prostates. However, no obvious differential expression pattern was observed in the immunohistochemistry of PAP and PSA, which showed a uniform staining of the secretory epithelia of the acini in all anatomic zones. The hybridization signals and immunoreactivity of PSP94 became reduced or lost in premalignant prostatic intraepithelial neoplastic lesions and different grades of prostatic carcinomas.

CONCLUSIONS

Fetal prostates at 6-7 months of gestation already synthesize PSA and PAP but not PSP94. The delayed expression of PSP94 appears to correlate with the development of the prostate gland. A differential expression pattern of PSP94 is demonstrated in different anatomical zones, showing that this protein is more expressed and synthesized in the acini in the peripheral zone than in the central and transition zones. However, such a zonal pattern is not seen in the immunohistochemistry of PSA and PAP. The present study also shows that PSP94 is downregulated in different grades of prostate cancers.

Mechanism of pellet coat rupture and its effect on drug release

In the formation of a coated controlled release preparation with functional coat layers, hydroxypropyl-methylcellulose was used to form a diffusion layer which swelled immediately upon wetting. Eudragit RS30D was used to form the outer retention layer. The rupture of pellet coat occurred when the Eudragit RS30D was unable to withstand the expansion in volume due to the influx of water and swelling of the hydroxypropylmethylcellulose diffusion layer. The sucrose core was able to contribute an osmotic effect. The hydrostatic pressure built up within the pellet can cause the pellet coat to rupture. Sodium chloride deposited in the diffusion coat was able to delay the bursting of the pellet coat. This was due to the competition for the imbibed water between sodium chloride and hydroxypropylmethylcellulose. The rupture of the pellet coat did not result in a total failure of the controlled drug delivery mechanism. Similar drug release rates were obtained irrespective whether there was a puncture in the pellet coat or not. Pressure built-up in the region away from the puncture pushed the core material towards the point of puncture and sealed the puncture point. In addition, the swelling of polymer around the point of rupture ensured continuity in the drug diffusion barrier.

An adaptive Bayesian pruning for neural networks in a non-stationary environment

Pruning a neural network to a reasonable smaller size, and if possible to give a better generalization, has long been investigated. Conventionally the common technique of pruning is based on considering error sensitivity measure, and the nature of the problem being solved is usually stationary. In this article, we present an adaptive pruning algorithm for use in a nonstationary environment. The idea relies on the use of the extended Kalman filter (EKF) training method. Since EKF is a recursive Bayesian algorithm, we define a weight-importance measure in term of the sensitivity of a posteriori probability. Making use of this new measure and the adaptive nature of EKF, we devise an adaptive pruning algorithm called adaptive Bayesian pruning. Simulation results indicate that in a noisy nonstationary environment, the proposed pruning algorithm is able to remove network redundancy adaptively and yet preserve the same generalization ability.

Effects of poly(vinylpyrrolidone) and ethylcellulose on alginate microspheres prepared by emulsification

Calcium alginate microspheres were prepared by an emulsification process. The effects of two co-polymers, namely poly(vinylpyrrolidone) and ethylcellulose, on the properties of the microspheres were studied. Microspheres prepared with and without poly(vinylpyrrolidone) were spherical and discrete. The microspheres containing poly(vinylpyrrolidone) exhibited a better flow property but the drug content was lower and the drug release rate higher. The method of incorporating poly(vinylpyrrolidone) was found to (significantly) affect the size distribution and drug content of the microspheres. Ethylcellulose produced marked aggregation of the microspheres which also showed a lower drug content, but a slower drug release. The retardation in drug release was attributed to the formation of aggregated microspheres with a less permeable matrix. The addition of triethyl citrate, which is a water-soluble plasticizer, was found to increase the rate of drug release while the use of a higher viscosity grade of ethylcellulose produced the opposite effect. Ethylcellulose improved the flowability of the microspheres to a greater extent than poly(vinylpyrrolidone).

Calculating prostate cancer volume preoperatively: the D'Amico equation and some other observations

PURPOSE

The primary morphological determinants of cancer progression in the prostate are tumor volume and the percentage of Gleason grades 4 and/or 5 disease. To date the best estimate of cancer volume before therapy has been serum prostate specific antigen (PSA) with Pearson's correlation coefficient value of approximately 0.5. Recently it was reported that prostate cancer volume calculated according to the formula, cancer specific serum PSA/amount of PSA leaking into the serum per cm.3 of cancer, highly correlates with actual cancer volume (R = 0.98). Because there is a definite need for greater accuracy in estimating cancer volume before therapy, we attempt to confirm this proposed equation in our radical prostatectomy series.

MATERIALS AND METHODS

We applied this equation to the initial 318 men with peripheral zone cancer treated only with radical prostatectomy at our institution who were followed for a mean and median of greater than 5 years. Calculated prostate cancer volume was determined according to the aforementioned equation with minor modifications, and correlated with the actual cancer volume measured in radical prostatectomy specimens. Pearson's correlation coefficient and the coefficient of determination were calculated using a linear regression model. Calculated prostate cancer volume was also previously used to predict pathological stage pT3. We compared calculated prostate cancer volume, clinical stage, Gleason grade and preoperative serum PSA in logistic univariate and multivariate regressions to predict stage pT3 disease.

RESULTS

Overall correlations for calculated prostate cancer volume were R = 0.537 and R2 = 0.289 (p <0.0001), which are much less than those previously noted (R = 0.98 and R2 = 0.96). As in the original report, we also divided our 318 cases into the 4 cancer volume subgroups of 0.5 cm.3 or less, 0.5 to 2.0, 2.0 to 4.0 and greater than 4.0 cm.3 (R = 0.251, 0.288, 0.382 and 0.462, and R2 = 0.063, 0.083, 0.146 and 0.213 alone respectively). There was an increasing trend for better R and R2 values with increasing prostate cancer volume. Calculated prostate cancer volume was less than 0.5 cm.3 in 156 of our 318 patients (49%) and less than 0 in 37 (11.6%). In these cases serum PSA alone strongly correlated with calculated prostate cancer volume (R = 0.877 and R2 = 0.77). Univariate analysis demonstrated statistical significance for prediction of stage pT3 disease, Gleason grade, clinical stage, serum PSA and calculated prostate cancer volume but multivariate analysis revealed statistical significance only for Gleason grade (p <0.0001) and clinical stage (p <0.0036). Values for PSA and calculated prostate cancer volume were not significant (p = 0.0640 and 0.7920, respectively).

CONCLUSIONS

Calculated prostate cancer volume did not predict cancer volume in our 318 patients who underwent radical prostatectomy. While we are uncertain how to interpret the excellent correlation of calculated prostate cancer volume with PSA, we believe that this correlation strongly suggests that most predictive information of calculated prostate cancer volume is related to serum PSA. Importantly in our 318 patients serum PSA was a much stronger predictor of cancer volume than calculated prostate cancer volume. As expected, Gleason grade and clinical stage are excellent predictors of stage pT3 disease but not of serum PSA or calculated prostate cancer volume.

Effect of cellulose derivatives on alginate microspheres prepared by emulsification

Generally discrete and spherical calcium alginate microspheres with a high drug encapsulation efficiency were readily prepared by an emulsification process. They were found to release drug rapidly. In the present study, co-polymer in the form of cellulose derivatives was added to sodium alginate in an attempt to modify the drug release profiles of the microspheres. The effects of cellulose derivatives on the morphology and drug encapsulation efficiency of the microspheres were also evaluated. The cellulose derivatives increased the degree of agglomeration of the microspheres. Small and spherical microspheres were produced from cellulose derivatives of low viscosity while larger microspheres which tended to be elongated were produced from cellulose derivatives of high viscosity. The drug encapsulation efficiency and the drug release profiles were influenced by the chemical nature of the cellulose derivative as well as its viscosity. The efficiency of drug encapsulation generally increased while the rate of drug release decreased with increasing viscosity of the cellulose derivatives. Less hydrophilic cellulose derivatives such as methyl cellulose and hydroxypropylmethyl cellulose were found to increase the efficiency of encapsulating sulphaguanidine, while more hydrophilic cellulose derivatives such as hydroxypropyl cellulose and carboxymethyl cellulose had the opposite effect. Among the cellulose derivatives used, only hydroxypropyl cellulose retarded the drug release of the microspheres.

Stability and statistical properties of second-order bidirectional associative memory

In this paper, a bidirectional associative memory (BAM) model with second-order connections, namely second-order bidirectional associative memory (SOBAM), is first reviewed. The stability and statistical properties of the SOBAM are then examined. We use an example to illustrate that the stability of the SOBAM is not guaranteed. For this result, we cannot use the conventional energy approach to estimate its memory capacity. Thus, we develop the statistical dynamics of the SOBAM. Given that a small number of errors appear in the initial input, the dynamics shows how the number of errors varies during recall. We use the dynamics to estimate the memory capacity, the attraction basin, and the number of errors in the retrieved items. Extension of the results to higher-order bidirectional associative memories is also discussed.

Attraction basin of bidirectional association memories

In this paper, we investigate the attraction basin of the bidirectional associative memory (BAM) model. The BAM is a two-layer heteroassociator that stores a prescribed set of bipolar library pairs. It consists of two layers of neurons. One layer has n neurons and the other has p neurons. We will first point out why the conventional energy approach cannot tell us about the attraction basin of each library pair. We then rigorously derive the statistical dynamics of the BAM, which shows how the upper bound on the number of errors changes during recalling for an arbitrary error pattern in the initial state. From the dynamics, we can estimate the attraction basin for the worst case errors, as well as the memory capacity and the number of errors in the retrieved pairs. The memory capacity is alpha rn, where alpha r (0 < alpha r < 1) depends on the ratio [formula: see text]. The number of errors in the retrieved pairs is [formula: see text] when the number of library pairs is alpha n. When r = 1, the lower bound on the attraction basin for the worst case errors is about 0.0068n.

Existence of iodine deficiency in Hong Kong--a coastal city in southern China

OBJECTIVE

Iodine deficiency is a serious public health problem worldwide which is associated with mental retardation and cretinism. In view of a high incidence of transient neonatal hypothyroidism and a relatively high mean cord blood thyrotropin (TSH) concentration, a pilot study was carried out to analyse the urine iodine excretion in Hong Kong, a coastal city in the southern part of China.

DESIGN

Early morning urine was collected from healthy volunteers including children (n = 104), adults (n = 112) and elderly subjects (n = 349). A semi-quantitative questionnaire survey on the pattern of food intake was conducted in the adults and elderly.

RESULTS

45.3% of the children, 51.7% of the adults and 55.3% of the elderly had urine iodine concentration below the criteria for iodine sufficiency (< 0.79 mumol/l). Iodine content in the drinking water and salt was low. A dietary survey revealed that seafood was not commonly consumed. 50-80% of the subjects never consumed high-iodine containing food such as seaweed, kelp or laver, and only 50% consumed seawater fish daily.

CONCLUSION

We confirmed that although Hong Kong is a non-goitrous area, iodine insufficiency exists. It is unsafe to assume that iodine deficiency does not exist in coastal urban areas.

Aggressive fibromatosis of the spermatic cord. A typical lesion in a "new" location

The authors describe a 31-year-old man with a 7 cm aggressive fibromatosis (desmoid tumor) of the spermatic cord presenting as a swelling in the left inguinal area that was excised along with the testis and cord. The desmoid tumor is histologically typical, but such tumors arising primarily from the paratesticular structures have apparently not been previously reported and the diagnosis would not be questioned if it not for the unusual site. This tumor is histologically and immunohistochemically indistinguishable from abdominal wall desmoid tumor, with or without Gardner's syndrome. Desmoid tumors at this location should be distinguished from reactive processes, such as pseudosarcomatous myofibroblastic proliferation (so-called "proliferative funiculitis") and inflammatory fibrous pseudotumor, all of which exhibit fibroblastic/myofibroblastic differentiation. Paratesticular fibrosarcoma and leiomyosarcoma should also be differentiated from desmoid tumor that does not have the metastatic potential of sarcomas. Thirty-four months post-operatively, an 8 cm local recurrence in the remaining portion of the left vas deferens causing left hydroureter and hydronephrosis was detected.

Drug encapsulation in alginate microspheres by emulsification

A method based on an emulsification process was developed for the production of calcium alginate microspheres. Isopropyl alcohol and acetone, which are strong dehydrating agents, were used to aid in the hardening and drying of the microspheres. However, the amount of drug encapsulated was very low. This was due to the drug being soluble in the dehydrating solvents. In the absence of the solvents a high percentage of drug was encapsulated, and this was further increased by forming the microspheres by phase inversion. It was also found that a suspension of the drug particles was required for effective microencapsulation. The efficiency of drug encapsulation generally increased with the ratio of drug to encapsulating material. The microspheres produced were free-flowing and most of them were smaller than 150 microns.

Absorption of intranasal salmon calcitonin in normal subjects and hypogonadic men

The absorption kinetics of intranasal salmon calcitonin were assessed in 4 normal subjects and 9 patients with Klinefelter's syndrome. After administration, absorption occurred within 5 minutes. There was a highly significant correlation between the amount administered and the amount absorbed (r = -0.83, P less than 0.0005).

Analgesic effect of intranasal salmon calcitonin in the treatment of osteoporotic vertebral fractures

Spinal collapse is a painful complication of osteoporosis. In this study, the analgesic effect of salmon calcitonin, administered intranasally (200 IU per day), was assessed in 18 patients with acute collapse of one to four vertebrae. Pain was evaluated by a descriptive pain scale (ie, Keele's) as well as by the daily consumption of analgesic drugs. When compared with placebo, intranasal salmon calcitonin significantly relieved pain and occasioned a decrease in the consumption of analgesic drugs. No major side effects were reported by the patients under study.

Labelled leucine uptake in the visual cells and pigment epithelium of young albino rats in response to different light-dark cycles

The leucine uptake in the visual cells and pigment epithelium were studied in the young albino rats after exposing to different light-dark cycles. Some form a cycle pattern was found in the visual cell layer and two peaks were recorded. The pattern on the uptake in the pigment epithelium was less distinct but at least a peak in the morning was recognized. The peaks could be shifted by manipulating the light-dark environment.