Intelligent Wireless Capsule Endoscopy for the Diagnosis of Gastrointestinal Diseases

Through a wireless capsule endoscope (WCE) fitted with a miniature camera (about an inch), this study aims to examine the role of wireless capsule endoscopy (WCE) in the diagnosis, monitoring, and evaluation of GI (gastrointestinal) disorders. In a wearable belt recorder, a capsule travels through the digestive tract and takes pictures. It attempts to find tiny components that can be used to enhance the WCE. To accomplish this, we followed the steps below: Researching current capsule endoscopy through databases, designing and simulating the device using computers, implanting the system and finding tiny components compatible with capsule size, testing the system and eliminating noise and other problems, and analyzing the results. In the present study, it was shown that a spherical WCE shaper and a smaller WCE with a size of 13.5 diameter, a high resolution, and a high frame rate (8-32 fps) could help patients with pains due to the traditional capsules and provide more accurate pictures as well as prolong the battery life. In addition, the capsule can also be used to reconstruct 3D images. Simulation experiments showed that spherical endoscopic devices are more advantageous than commercial capsule-shaped endoscopic devices for wireless applications. We found that the sphere's velocity through the fluid was greater than the capsule's.

Surgical robotic arm control for tissue ablation

In the technology driven era, robot assisted surgery is gradually emerging as a revolutionized surgical procedure over traditional laparoscopic method. Despite the concerns about robotic surgery for minimally invasive surgical procedures, robotized surgical arms have been used in many hospitals. Certain surgical procedures require removal of a segment of an organ or body part like excision biopsy, linear thin layer of soft tissue, triangular mass, and tangential excision in burn management, where shaving-off at an angle of the tissue layer to be removed. For such minimally invasive procedures, we have designed a surgical arm governed by a rotary flexible joint. The surgical arm has a medical grade scalpel in its one end and the other end is connected to a D.C. servo motor. The motion of the surgical arm is controlled by the newly designed non-integer order controller. We have experimentally demonstrated the functioning of the surgical arm by ablating the tissue in-vitro. Our surgical robotic arm is cost effective, high precision and free from potential human errors.

Association of progesterone receptor gene polymorphism (PROGINS) with endometriosis, uterine fibroids and breast cancer

Endometriosis, uterine fibroids and breast cancer are female health disorders associated with a great deal of morbidity. Since all these disorders are hormone responsive, our present study has been carried out to identify the association of 306bp Alu insertion polymorphism in intron 7 of progesterone receptor gene (PROGINS). DNA was isolated from the blood samples of 445 Asian Indian women, which included 100 endometriosis, 80 fibroids and 157 cases of breast cancer along with 108 age matched normal healthy women as controls. PROGINS polymorphism was assessed by PCR followed by agarose gel electrophoresis. Results showed that T2 allele frequency is 5%, 10% and 14.6% in endometriosis, uterine fibroids and breast cancer, as compared to 5.5% in controls. This indicates that PROGINS can be considered as a predisposing risk marker for breast cancer but not for endometriosis and uterine fibroids.

Brain tissue phantoms for optical near infrared imaging

In this study, solid, stable, and cost-effective optical phantoms of scalp-skull, white matter and grey matter are developed by inverse method. To begin with, to obtain a range of optical parameters, absorption and reduced scattering coefficients (mu(a) and mu(s)', respectively), 20 homogeneous phantoms were made of paraffin wax by using optically contrast black and highly scattering white colouring materials in different combination. By comparing the measured reflectance values for each phantom got from the four channel reflectometer with that obtained from steady-state diffusion equation, the values of mu(a) and mu(s)' were determined. Next, phantoms which exhibit specific optical properties of scalp-skull, white and grey matter are developed iteratively by comparing actual reflectance measurements got by adjusting the colour concentration with the predicted reflectance values from the diffusion equation. This is done as follows: to obtain mu(a) of 0.04 mm(-1) for scalp-skull, 9.5 mg of black dye per 100 ml of wax added since more attenuation of light occurs in bone tissue. To obtain a mu(s)' 6.0 mm(-1) for white matter in brain tissue, 190 mg of white dye per 100 ml of wax was used to facilitate more scatter of light. The colour concentrations of phantoms were then adjusted to obtain the predetermined values of optical parameters for scalp-skull, grey and white matter.

Controlled release of lysozyme from succinylated gelatin microspheres

Gelatin was anionized to increase the carboxylic acid groups through succinylation. Succinylation of gelatin was performed using varying amounts of succinic anhydride. This gave various percentages of substitution. Lysozyme, a cationic antibacterial enzyme, which has important applications in the reduction of prosthetic valve endocarditis, was chosen as a model protein drug. Microspheres were prepared using unmodified gelatin and succinylated gelatin (SG) and lysozyme was incorporated into them. The percentage loading and release profiles of lysozyme for gelatin and SG microspheres were evaluated and compared. It was found that the SG microspheres exhibited higher loading efficiency for lysozyme (50%) than the unmodified gelatin microspheres. The in vitro release of lysozyme from SG microspheres occurred up to 122 h, compared to 96 h for gelatin microspheres, for the release of most of the lysozyme incorporated. This prolonged release of lysozyme from SG microspheres was attributed to the electrostatic interaction between the cationic lysozyme and the anionic SG microsphere carrier.

Collagen-chitosan polymeric scaffolds for the in vitro culture of human epidermoid carcinoma cells

A biodegradable polymer scaffold was developed using collagen and chitosan, in the form of interpenetrating polymeric network (IPN), for in vitro culture of human epidermoid carcinoma cells (HEp-2, Cincinnati). Glutaraldehyde was used as cross-linking agent for the development of scaffold. Various types of scaffolds were prepared using different proportionate mixtures of collagen and chitosan solutions in the ratio of 3:7, 4:6, 5:5, 6:4 and 7:3 (collagen:chitosan). These scaffolds were fully characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Equilibrium swelling studies were carried out in phosphate buffer of physiological pH (7.4) to study its swelling characteristics at slightly alkaline pH. The scaffold that showed optimum swelling property was selected as the best scaffold for performing in vitro culture studies. In vitro culture studies were carried out using HEp-2 cells, over the selected scaffold and its growth morphology was determined through optical photographs taken at different magnifications at various days of culture. The results of the above studies suggest that the scaffolds prepared from collagen and chitosan can be utilized as a substrate to culture HEp-2 cells and can also be used as an in vitro model to test anticancerous drugs.

5-fluorouracil (5-FU) induces the formation of giant cells and sloughing of seminiferous epithelium in the rat testis

The chemotherapeutic agent, 5-fluorouracil (5-FU) has been widely used in the treatment of a variety of cancers. Its effect on the testis has not been substantially studied. Present study was conducted to evaluate the gonadotoxicity of 5-FU in male albino rats. Animals were injected with single dose of 5-FU (10, 50 and 100 mg/kg, i.p.) and sampled on 1, 3, 15 and 30 day post exposure. Animals were anaesthetised, testes were perfusion fixed by Bouin's fluid. Five micron thick paraffin sections were stained with haematoxylin and eosin. Slides were screened for the incidence of partially and extensively sloughed tubules. Data were analysed by Mann Whitney 'U' test. Only 100 mg/kg induced multinucleated cells on 3rd day. All doses of 5-FU induced sloughing of the seminiferous epithelium. Maximum number of partially sloughed tubules were seen on third day. Partial sloughing was not dose dependent except on 15th day. The extensive sloughing was dose dependent except on 30th day. The result indicates that all the doses of 5-FU tested in this study cause sloughing of epithelium and only 100 mg/kg induces the formation of giant cells on third day.

Reduction of calcification by various treatments in cardiac valves

The importance of glutaraldehyde pretreated bioprosthetic heart valves fabricated from bovine pericardium or porcine aortic valves is well realized in the management of valvular heart diseases. But, calcification limits the durability and is the most frequent cause of failure of these bioprosthetic heart valves. Various research groups in the world are actively involved in describing, understanding, and preventing calcification of bioprosthetic heart valves. Since there is no satisfactory clinical means for preventing or treating this disorder, attempts are made to improve the anticalcification properties of the replacement valves in the preparation stage itself. Research in this area is very active, and many newer approaches are made to mitigate the problem. An attempt has been made in the present article to review various theories put forward to explain the causative factors involved and mechanistic aspects of biocalcification and to present various strategies attempted for the prevention of calcification with the special feature on the work done in the area in our laboratory.

New treatments using alginate in order to reduce the calcification of bovine bioprosthetic heart valve tissue

Calcification limits the functional lifetime of cardiac valve substitutes fabricated from glutaraldehyde preserved bovine pericardium. Host factors, mainly younger age, and implant factors, mainly glutaraldehyde cross-linking, are implicated in the calcification process. Glutaraldehyde cross-linking is believed to activate the potential sites in the tissues for biocalcification. In the present work, we investigated the possibility of using alginate azide (AA) instead of glutaraldehyde for the preservation of pericardial tissues in order to enhance the durability of bioprosthetic heart valves. Grafting with poly(GMA-BA) copolymer to the alginate azide cross-linked pericardial (AACPC) tissue was carried out to obtain better stability, strength, and anticalcification properties. The strength property and thermal stability of the AA cross-linked tissues were studied. Calcification studies in rat subdermal models reveal that AA cross-linking reduces the calcification to negligible levels. After 30 days implantation, the calcium content was found to be 10.4 +/- 1.2 and 6.1 +/- 0.3 micrograms mg-1 for untreated AACPC and polymer grafted AACPC, respectively, compared to a value of 100 +/- 1.2 micrograms mg-1 calcium recorded for control glutaraldehyde cross-linked pericardial (GCPC) tissues.

Transrectal ultrasonography versus computed tomography in staging rectal carcinoma

BACKGROUND

Since therapy of rectal carcinoma depends on the extent of disease, staging becomes important.

AIM

To assess the ability of transrectal ultrasonography (TRUS) and computed tomography (CT) to stage rectal carcinoma.

METHODS

Ten patients with rectal carcinoma were examined by TRUS and plain and contrast-enhanced CT scan; their findings were compared with each other and with those at surgery.

RESULTS

TRUS identified wall invasion in all ten cases and perirectal fat infiltration in all five cases in whom these were present. Node involvement was detected in five cases on TRUS and two of six cases on CT. Metastasis to bladder (one case) was not recognized by TRUS but was seen on CT.

CONCLUSION

TRUS is inexpensive and superior to CT in staging early rectal carcinoma; limited depth of penetration is its major limitation. CT is useful for the diagnosis of advanced disease.

Immunoglobulin and C3-activator profile of the microbiology laboratory worker

The levels of immunoglobulin, C3-Activator and C3c in the sera of members of staff who have been continuously engaged for upwards of 10 years in the microbiological routine laboratory of a teachings hospital were determined. These were compared with the local normals, with those of the junior members of staff in the same laboratory but who had put in less than 5 years continuous service and with a control group. The means in all five determinations were much higher in the senior members of staff than the normal standards of the area, particularly the IgG, which was almost double the local normals. The levels for the junior staff were on the whole slightly higher than the control group. The increase in the levels of immunoglobulins with corresponding increases in C3-Activator and 3Cc suggest that immunological reactions, with the binding of complement in the alternate and classical pathways of activation are taking place in most of these senior workers. In the absence of any manifest illness in the senior staff, the findings may suggest a high degree of immunological protection.

Development of hydroxyapatite derived from Indian coral

A simple method of converting the calcium carbonate skeleton of the corals available in the Indian coast into hydroxyapatite granules has been developed. By heating the coral to 900 degrees C, the organic materials were eliminated. Powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were employed to characterize the coral and to optimize the processing parameters as well as to confirm the hydroxyapatite formation. The coral used exhibits the presence of both aragonite and calcite phases (dimorphism). At a temperature of 900 degrees C the coral was found to decompose all the carbonate phases. The pre-heated coral is converted into hydroxyapatite by a chemical exchange reaction with di-ammonium phosphate under hydrothermal conditions. The hydroxyapatite obtained was in powder form and does not contain any impurities. The in vitro solubility test of the apatite granules performed in Gomoris, Michalelis, Sorensens, Ringer's and phosphate buffer of pH 7.2 and de-ionized water indicated the stability of the coralline hydroxyapatite.

Rate-controlling biopolymer membranes as transdermal delivery systems for nifedipine: development and in vitro evaluations

Membrane permeation-controlled transdermal delivery devices for the controlled delivery of nifedipine were developed using collagen (which was extracted from calf fetus skin) and chitosan membranes as rate-controlling membrane. To increase the stability of nifedipine in the systems, alginate gel was used as drug reservoir. Transdermal devices were fabricated by adhesive sealing techniques. In vitro drug release studies were carried out using modified Franz diffusion cells. Drug release was found to depend on the type of membrane used to control the drug delivery, suggesting that drug delivery is efficiently controlled by the rate-controlling membranes.

Polymer-coated gelatin capsules as oral delivery devices and their gastrointestinal tract behaviour in humans

In oral delivery of protein and peptide drugs there is a great need for suitable devices for delivering the therapeutic agent-incorporated microspheres selectively in the intestine. It is essential that the drug-loaded multiple unit carrier system should be protected from the harsh environment of the stomach and deliver the carrier system in the large intestine where drug action or absorption is desired. Gelatin capsules were coated with various concentrations of sodium alginate and cross-linked with appropriate concentrations of calcium chloride and tested in vitro for resistance to gastric and intestinal medium. Gelatin capsules coated with 20% w/v of the polymer which gave the most promising result in vitro were evaluated in human volunteers for their in vivo gastro intestinal tract behaviour. The radiographical studies show that while the uncoated gelatin capsules disintegrated in the stomach within 15 min of ingestion, the alginate coated gelatin capsules remained intact as long as they were retained in the stomach (up to 3 h) and then migrated to the ileocecal region of the intestine and disintegrated.

Recent developments of collagen-based materials for medical applications and drug delivery systems

In this review, an attempt was made to summarize some of the recent developments in the application of collagen as a biomaterial and in drug delivery systems. The main applications covered include: collagen for burn/wound cover dressings; osteogenic and bone filling materials; antithrombogenic surfaces; and immobilization of therapeutic enzymes. Recently, collagen used as a carrier for drug delivery has attracted many researchers throughout the world. The use of collagen for various drug delivery systems has also been reviewed in this article. Collagen-based drug delivery systems include: injectable microspheres based on gelatin (degraded form of collagen); implantable collagen-synthetic polymer hydrogels; interpenetrating networks of collagen; and synthetic polymers collagen membranes for ophthalmic delivery. Recent efforts to use collagen-liposomal composites for controlled drug delivery, as well as collagen as controlling membranes for transdermal delivery, were also reviewed. In this review, the main emphasis was on the work done in our laboratory.

Azo polymeric hydrogels for colon targeted drug delivery

Azo polymeric hydrogels were developed for colon specific targeting. Methacryloyloxy azobenzene was synthesized and hydrogels were prepared by copolymerizing with hydroxyethyl methacrylate. These hydrogels were characterized by various spectral techniques such as Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Equilibrium swelling measurements of the hydrogels were carried out in distilled water and also in simulated gastric and intestinal fluids. The in vitro release studies of the incorporated 5-flurouracil were carried out in simulated gastric and intestinal fluids. The in vitro release profiles of the drug were also obtained in the presence of azoreductase in the culture of intestinal flora. The release was faster and almost followed a zero order pattern. This can be attributed to the cleavage of the azo crosslinks in the hydrogel by the azoreductase and the release of the entrapped drug at the site of targeting i.e., colon.

Neuroticism and stressful life events in patients with non-ulcer dyspepsia

Hindi adaptation of the Middlesex Hospital Questionnaire (MHQ), Brief Psychiatric Rating Scale and Presumptive Stressful Life Events Scale were used to measure neuroticism, psychiatric morbidity and stressful life events in 35 patients with non-ulcer dyspepsia (NUD), 22 cass of peptic ulcer disease (PUD), 65 irritable bowel syndrome (IBS) and 45 age and sex matched healthy controls. NUD subjects had significantly higher total MHQ scores (28.8 +/- 11.3; p < 0.001) and scores in subscales of somatization (7.8 +/- 3.4; p < 0.001) and hysterical personality traits (5.5 +/- 2.8; p < 0.01) compared to healthy controls. MHQ scores in IBS subjects was significantly higher than in NUD, but in PUD subjects it was in-between NUD and healthy controls. Psychiatric morbidity, as assessed by Brief Psychiatric Rating Scale, was significantly higher in patients with NUD and IBS than in normal controls. Stressful Life event score was statistically similar in all the groups.

Development and in vitro evaluation of chitosan-based transdermal drug delivery systems for the controlled delivery of propranolol hydrochloride

Membrane permeation-controlled transdermal drug delivery systems were prepared using the natural polymer, chitosan. An adhesive sealing technique was used to construct the devices. Propranolol hydrochloride was selected as the model drug for the present study. Chitosan membranes with different permeability to propranolol hydrochloride obtained by controlled cross-linking with glutaraldehyde were used to regulate the drug release in the devices. Chitosan gel was used as the drug reservoir. The ability of these devices to deliver the drug while supported on rabbit pinna skin was tested by conducting in vitro studies in modified Franz diffusion cells. The drug release profiles showed that the drug delivery is completely controlled by the devices. The rate of drug release was found to be dependent on the type of membrane used.

Controlled release systems for proteins based on gelatin microspheres

The preparation and characterization of biodegradable gelatin microspheres for the controlled release of peptides and proteins has been investigated. Bovine serum albumin (BSA) was chosen for incorporation into the gelatin microspheres and the spheres were characterized for the in vitro release of BSA and other properties. BSA was labelled with fluorescein isothiocyanate (FITC) for easy analysis. FITC-BSA was entrapped into the gelatin microspheres using a polymer dispersion technique developed in our earlier studies. The morphological characteristics of microspheres were analysed by optical and scanning electron microscopy (SEM). The optical and SEM photographs of FITC-BSA microspheres showed the solid spherical nature of the spheres. The entrapment efficiency of FITC-BSA was about 62%. The in vitro release pattern of FITC-BSA showed that 51% of the entrapped drug was released during the first day and the release followed approximate zero order kinetics from day 2 onwards. The total release of FITC-BSA lasted for about 8 days. SDS-PAGE analysis revealed that BSA was not degraded by this preparation of microspheres.

Implantable controlled delivery systems for proteins based on collagen--pHEMA hydrogels

Co-polymeric hydrogels of collagen and poly(hydroxyethyl methacrylate) (pHEMA) were prepared using an ammonium persulphate-sodium metabisulphite redox initiation technique. Fluorescein isothiocyanate (FITC)-labelled bovine serum albumin (BSA) was entrapped into these hydrogels. These gels were modified differently by external cross-linking and made highly porous by incorporation of ethylene glycol. The morphological characteristics of the gels containing FITC-BSA before and after release were studied. The in vitro release of FITC-labelled BSA was studied in phosphate buffer, pH 7.4, at 37 degrees C. The results clearly indicated that collagen-pHEMA hydrogels release FITC-BSA in a zero-order fashion. In the case of uncross-linked hydrogels, the release of FITC-BSA was about 81% within 8 d, compared to 49% for the same period in the case of cross-linked hydrogels. It was also observed that in the case of porous hydrogels the release was very fast (19% in the first hour) and lasted for about 12 h, releasing 76% of FITC-BSA. These results clearly indicated that collagen-pHEMA hydrogels released BSA in a zero-order fashion and that the release rate can be programmed by appropriate modification of the hydrogel matrices.

Controlled release of anticancer drug methotrexate from biodegradable gelatin microspheres

Biodegradable hydrophilic gelatin microspheres containing the anticancer drug methotrexate (MTX) of different mean particle sizes (1-5, 5-10, and 15-20 microns) were prepared by polymer dispersion technique and crosslinked with glutaraldehyde. The microspheres were uniform, smooth, solid and in the form of free-flowing powder. About 80 per cent of MTX was incorporated in gelatin microspheres of different sizes. The in vitro release of MTX was investigated in two different media, namely simulated gastric and intestinal fluids. The release profiles indicated that gelatin microspheres released MTX in a zero-order fashion for 4-6 days in simulated gastric fluid and for 5-8 days in simulated intestinal fluid. The rate of release of MTX decreased with increase in the particle size of the microspheres. MTX release was faster in gastric fluid when compared to intestinal fluid.

Evaluation of Manning's criteria in the diagnosis of irritable bowel syndrome

Six symptoms of Manning et al are widely used in clinical practice to diagnose irritable bowel syndrome (IBS). We studied 123 patients to evaluate the diagnostic value of Manning's criteria, using a preformed bowel symptom questionnaire which included these six symptoms. This study included 65 patients with IBS, 35 patients with non-ulcer dyspepsia, 23 patients with organic diseases of colon and 45 healthy controls. Sensitivity of presence of three or more symptoms of Manning's criteria discriminating irritable bowel syndrome from all other groups was 66.1%. Manning's criteria discriminated irritable bowel syndrome from organic diseases of colon with specificity and positive predictive value of 66.9% and 82.6%. When irritable bowel syndrome was compared with non-ulcer dyspepsia and healthy controls, specificities of Manning's criteria were 91.4% and 93.3% and positive predictive values 93.4% and 93.4% respectively.

Inhibition of methyl mercury chloride-induced chromosomal damage by gamma-linolenic acid

The genotoxic potential of methyl mercury chloride (MMC) was investigated in human lymphocyte cultures by tests for chromosomal aberrations and sister chromatid exchange. The protective role of gamma-linolenic acid, a derivative of dietary essential fatty acid, on MMC-induced genetic damage was evident from the reduced frequency of aberrations and sister chromatid exchanges.

False positive ECG and coronary heart disease

In 1983, we carried out a cross-sectional, rural community based study and highlighted an abysmally low prevalence of probable coronary heart disease in resting electrocardiogram. A seven year follow-up (1983-1990) of 179 suspects showed no morbidity or mortality from coronary heart disease. Eighty one out of 98 suspects tested negative on a symptom limited maximal exercise test. Though seventeen suspects had an asymptomatic exercise-induced ST depression (> 1.0 mm) their haemodynamic response to exercise and effort tolerance was excellent. Of the twelve subjects who took a repeat exercise test six months later, eleven failed to show ST depression on exercise. We attribute the false positivity of exercise test and its poor reproducibility to labile electrocardiographic changes unmasked by exercise.

Mutagenic activation of 4-aminobiphenyl and its N-hydroxy derivatives by microsomes from cultured human uroepithelial cells

Activation of the human bladder carcinogen 4-aminobiphenyl (ABP) and its N-hydroxy derivatives was investigated using lysates and subcellular enzyme preparations from cultured human uroepithelial cells (HUC). Mutagenic activation was determined using Salmonella typhimurium strains TA98; TA98/1,8-DNP6, a derivative deficient in acetyl coenzyme A:N-hydroxyarylamine O-acetyltransferase (OAT); and YG1024, a derivative of TA98 with elevated OAT activity and enhanced sensitivity to mutation by N-hydroxyarylamines. Mutagenicity of ABP catalyzed by HUC microsomes was detected in YG1024 but not in the parent strain TA98. HUC microsomes also catalyzed the mutagenic activation of N-hydroxy-4-acetylaminobiphenyl (N-OH-AABP) and the relative sensitivity of the tester strains was YG1024 > TA98 > TA98/1,8-DNP6, indicating N-hydroxy-4-aminobiphenyl (N-OH-ABP) as the mutagenic intermediate. In contrast, the mutagenic activity of N-acetoxy-4-acetylaminobiphenyl incubated with HUC microsomes was approximately equal in TA98 and YG1024, and may involve N-acetoxy-4-aminobiphenyl (N-OAc-ABP) as the intermediate. High pressure liquid chromatography (HPLC) of the DNA hydrolysate obtained after incubation of [3H]N-OH-ABP with YG1024, showed N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-ABP) as the primary adduct, based on mobility of the radioactivity in comparison with the synthetic standard. Additionally, HUC microsomes catalyzed the binding of [3H]N-OH-ABP to RNA in the presence of 4-acetylaminobiphenyl (AABP), N-OH-AABP and acetyl coenzyme A as acetyl donors, and this binding was blocked by paraoxon. The hydrolysate obtained from incubation of DNA with [3H]N-OH-ABP and HUC microsomes, with AABP as acetyl donor, revealed the formation of dG-ABP adduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Propranolol hydrochloride release behaviour of crosslinked chitosan membranes

Chitosan membranes of 20 microns thickness were prepared by a solvent evaporation technique and crosslinked with different concentrations of glutaraldehyde to obtain membranes of various degrees of crosslinking. These membranes were characterized by thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and tensile strength studies. The effect of crosslinking on the permeability of membranes to propranolol hydrochloride was evaluated by permeation studies conducted in static glass diffusion cells. A decrease in the thermal stability of chitosan membranes due to crosslinking was observed. The tensile strength of the membranes was improved by crosslinking. The introduction of crosslink points within the membrane reduced its permeability to propranolol hydrochloride as evidenced by decreased permeability and diffusion coefficients. Permeability studies revealed the operation of a pore mechanism in the transport of hydrophilic agents such as propranolol hydrochloride through chitosan and crosslinked chitosan membranes.

Studies on the carboxymethyl chitosan-containing liposomes for their stability and controlled release of dapsone

Stable liposomes containing carboxymethyl chitosan (CMC) were prepared and characterized. CMC was introduced in the phosphatidyl choline (PC) liposomes by different methods; firstly, CMC in a free state in the aqueous phase; secondly as a coat (coupled); and finally as a conjugate of dapsone. The stability of liposomes was assessed by their disintegration in ethanol and surfactants. Both hydrophilic bromothymol blue and lipophilic dapsone were encapsulated in these liposomes and their in vitro release studies were carried out at 37 degrees C using different media, namely, phosphate buffer (pH 7.4), 0.02 N-HCl and 1% mouse plasma. The conjugate of dapsone with CMC present in PC liposomes gave the best results in its stability as compared to other modified liposomes. The release data of dapsone also confirmed the results of the stability studies on liposomes. CMC-dapsone conjugate released the dapsone much slower in all three media than did PCCMC and PCCMC-coat liposomes.

Solid tumour chemotherapy using implantable collagen-poly (HEMA) hydrogel containing 5-fluorouracil

Implantable collagen-poly(HEMA) hydrogels containing the anticancer drug 5-fluorouracil (5-FU) have been prepared and evaluated for their efficacy towards a solid tumour fibrosarcoma in Wistar rats. The tumour was developed by inoculation of a 10% tumour-cell suspension in the anterior aspect of the hind limb. Four groups were studied--untreated control, intratumoural injection of free 5-FU, subcutaneous implantation of placebo and implantation of 5-FU-bearing hydrogel pellets (10 mm diameter x 1 mm thick) containing the drug in close proximity to the tumour. The hydrogel showed an improved antitumour activity over free 5-FU as evidenced by the gross tumour weight assessments and by [3H]thymidine incorporation in-vitro. This was attributed to the controlled and slow release of 5-FU compared with free 5-FU over the same period of treatment. The implantation of hydrogel could thus be a potential alternative to free 5-FU therapy in the treatment of solid tumours such as fibrosarcoma.

Effect of surfactants on the stability of modified egg-yolk phosphatidyl choline liposomes

Disintegration by surfactants on egg-yolk phosphatidyl choline (PC) vesicles, stabilized with polycholesteryl methacrylate and carboxy methyl chitosan, was investigated by measuring the amount of marker dye (bromothymol blue) released from the vesicles. In all the studies at pH 7.4 anionic and nonionic surfactants caused vesicle disintegration at low concentrations while cationic surfactants produced breakdown of vesicles at high concentrations. It was found that the modified liposomes disintegrated in the following order: Polymeric liposomes less than carboxymethyl chitosan coated/stearic acid/oleic acid containing PC liposomes less than cholesteryl methacrylate monomer containing PC liposomes/PC liposomes Polymeric liposomes were found to be the most stable compared with all other types. This may be explained due to the filling of the pores in the lipid structure which in turn block the surfactant penetration into phospholipid bilayers. In contrast to unsaturated fatty acid (oleic acid) saturated fatty acid (stearic acid) containing liposomes are more stable.

In vivo biocompatibility of collagen-poly(hydroxyethyl methacrylate) hydrogels

Collagen-p(HEMA) hydrogels were subcutaneously implanted in rats for up to 6 month and the immediate short- and long-term tissue response to these implants was studied. Histopathological data indicated that the tissue reaction at the implant site progressed from an initial acute inflammatory response characterized by the presence of eosinophils and polymorphs to a chronic response marked by few macrophages, foreign body giant cells and fibroblasts. After one month a very thin fibrous capsule (approximately 11 microns thick) was observed around the implant. Even 6 month post-implantation, the capsule thickness was maintained at about 11-12 microns. No necrosis, calcification, tumorigenesis or infection was observed at the implant site up to 6 month. Fibrous capsule analysis showed that the collagen content and the capsule thickness were well within the threshold limits. The collagen-p(HEMA) hydrogels were found to be well-tolerated, non-toxic and highly biocompatible.

Gastrointestinal colonization with yeast species and Candida septicemia in very low birth weight infants

Yeasts may gain entry into the blood via routes such as intubation, intravenous catheterization or by direct persorption from the gut. The latter route becomes important when the numbers of commensal yeasts in the gut exceeds a threshold which may vary between animal species. In a prospective study utilizing serial, twice weekly quantitative stool cultures during the first 6 weeks of life of 40 very low birth weight infants, we found a threshold of 8 x 10(6) Candida colony-forming units/gram of stool. Beyond this threshold 50% of the infants developed gastrointestinal symptoms and 28.5% developed systemic sepsis within 1 to 3 weeks of heavy colonization. The gastrointestinal colonization rate was 62.5% (25/40) with 66% having Candida colony-forming units greater than 8 x 10(6)/g stool.

Prostaglandins can modify gamma-radiation and chemical induced cytotoxicity and genetic damage in vitro and in vivo

The effect of prostaglandin E1, E2, and F2 alpha on gamma-radiation, benzo(a)pyrene and diphenylhydantoin-induced cytotoxicity in vivo and genotoxicity in vitro was investigated. Prostaglandin E1 prevented both cytotoxic and genotoxic actions of all the three agents, where as both PGE2 and PGF2 alpha were ineffective. In fact, it was seen that both PGE2 and PGF2 alpha are genotoxic by themselves. Gamma-linolenic acid and dihomogamma-linolenic acid, the precursor of PGE1 were also as protective as that of PGE1, where as arachidonic acid, the precursor of 2 series PGs, has genotoxic actions to human lymphocytes in vitro. These results suggest that prostaglandins and their precursors can determine the susceptibility of cells to cytotoxic and genotoxic actions of chemicals and radiation. This study is particularly interesting since, it is known that some tumor cells contain excess of PGE2 and PGF2 alpha and many carcinogens can augment the synthesis of 2 series of PGs.

Cytogenetic effects of ribavirin on mouse bone marrow

The micronucleus test and mitotic chromosome analysis were used to study the in vivo mutagenic activity of ribavirin on bone marrow cells of Swiss albino mice. To determine the incidence of micronuclei, mice were injected i.p. twice, at an interval of 24 h. with the drug at doses of 20, 100 and 200 mg/kg. Animals were killed 6 h after the second dose and bone marrow was examined for the presence of micronuclei in developing erythrocytes. Ribavirin significantly (P less than 0.05) induced micronuclei in polychromatic erythrocytes at all doses. A study was conducted to investigate the cytogenetic effect of the drug on mitotic chromosomes. Ribavirin at 200 mg/kg/day was administered to mice for 3 and 5 days. Repeated treatment with the high dose of ribavirin produced a highly significant (P less than 0.02) increase in abnormal metaphase spreads. The results indicate that ribavirin is mutagenic to bone marrow cells of mice as evaluated by the micronucleus test and by chromosome analysis.

Passive neonatal thrombocytopenia. A case study of factors predicting the response to i.v. IgG therapy

A term male infant was noted at birth to have petechiae over the face and trunk and a platelet count of 3 x 10(9) per L. Maternal immune thrombocytopenia (ITP) was suspected from the clinical data and confirmed by the presence of antiplatelet antibody (both in the mother and infant) detected by recently described flow cytometry method. Initial treatment with exchange transfusions, platelet transfusions, steroids, failed to correct thrombocytopenia and, hence, seven doses of high-dose gamma globulin (IV-IgG) were given intravascularly. Initiation of IV-IgG was followed by stabilization of platelet counts with marked reduction in the need for platelet transfusions. In this case of passive ITP, the therapeutic efficiency of high dose IV-IgG seems to depend upon maintaining a certain critical level of serum IgG (which in turn may depend upon the serum antiplatelet antibody titers).

Effect of nitroxazepine on bone marrow cells of mice

The antidepressant drug, nitroxazepine, was tested in mice for mutagenicity in bone marrow cells by a micronucleus test. The drug was administered orally at a dose of 4.5, 9, and 13.5 mg per mouse. The results show that the drug is found to be mutagenic in mouse bone marrow cells.

Lupus anticoagulants in children

Although a great deal of information is available in the literature on the frequency, clinical/laboratory findings and significance of lupus anticoagulants in adults, little is known about such acquired inhibitors in children. Clinical and laboratory findings are presented on seven non-hemophiliac children, four females and three males, ranging in ages from three to 14 years, who developed such inhibitors. In most, the inhibitor is a transient phenomena and is not associated with a bleeding or thrombotic diathesis.

Acquired von Willebrand's syndrome associated with an extranodal pulmonary lymphoma

A case of acquired von Willebrand's syndrome associated with an extranodal pulmonary lymphoma is reported in a 58-year-old man. His initial factor VIII-von Willebrand factor (vWF) complex parameters included a factor VIII activity of 29 U/dL, a vWF protein of 17 U/dL, and a ristocetin cofactor of less than 10 U/dL. A specific factor VIII inhibitor could not be demonstrated in mixtures of his plasma and normal pooled plasma nor could immune complexes of IgG-factor VIII be detected in similar mixtures using protein A in a solid phase. Following surgical removal of the patient's tumor, all factor VIII-vWF complex parameters returned to normal. Immunoperoxidase stains of the lymphoid tumor cells were negative for von Willebrand protein. The patient's acquired von Willebrand's syndrome recurred approximately one year later, presumably indicative of recurrent lymphoma.

Effect of primidone in somatic and germ cells of mice

Primidone, an anti-convulsant drug, was tested in mice for mutagenicity in somatic cells by the micronucleus test and in germ cells by the sperm-head abnormality assay. Mice were treated orally with the drug at doses of 4.37, 8.75 and 13.11 mg/mouse. The results indicate that the drug is capable of inducing mutations both in somatic and germ cells of mice.

The effectiveness of antenatal education of Pakistani and Indian women living in this country

Eighty-two Asian women (mostly Muslims) living in East London were prospectively studied through their pregnancy and delivery. Their infants were assessed during the second year of life for growth, nutrition, morbidity, development and vaccination history. There was no increase in perinatal or infant mortality over the general population in the same borough, though there was increased infant morbidity, most commonly iron deficiency (in 25%), and one child with subclinical rickets. One child had a genetic neurodegenerative disorder. The incidence of low birth weight babies was only slightly greater than that of the district as a whole, but after 1 year of age they were less well grown than the population studied by Tanner & Whitehouse. Sixty-four per cent of the women started to breast feed, but many also gave artificial milk and they usually ceased to breast feed earlier than most women in the same district. When half of the women were randomly allocated to receive specialized education, with the others acting as controls, very few attended and little benefit was detected. Though the significance is doubtful, the infants of those educated did tend to be better grown (especially in length), be less likely to have development well below average, have reduced morbidity and have more complete immunization schedules than those of the women not receiving education. This study shows no benefit due to antenatal education, but suggests that the children have advantages when their mothers have the drive to attend the education sessions.

Lack of clastogenic effects of irradiated glucose in somatic and germ cells of mice

The clastogenic ability of irradiated glucose was evaluated using the micronucleus test in bone marrow cells and the chromosomal aberration assay in the spermatogonial cells of mice. Glucose was irradiated with 0.2, 2.0, 20 and 50 kGy of gamma-rays and administered to mice for various periods. No evidence of mutagenic effects was observed in somatic or germ cells.

Lectin histochemistry of complex carbohydrates in human cervix

Complex carbohydrates in the human cervix were studied histochemically using lectins conjugated to horseradish peroxidase and correlated procedures. Stratified squamous epithelium of the exocervix and columnar epithelium of the endocervix in some, but not all specimens showed staining for terminal alpha-N-acetyl-D-galactosamine, alpha-D-galactose, beta-D-galactose and alpha-L-fucose. The staining for alpha-N-acetylgalactosamine and alpha-galactose, the terminal sugars in blood group A and B antigens respectively, corresponded to a large extent with ABO blood type. One exception was the lack of staining for terminal alpha-N-acetylgalactosamine in endocervical secretions in three of nine blood type A patients. A second exception was the staining for terminal alpha-galactose in endocervical secretions in about half of blood type O and A specimens. The type and amount of glycoprotein formed by endocervical columnar cells differed according to location in superficial compared with deep portions of the glands and according to location at the junction with exocervix compared with the more internal regions. Staining of endothelial cells for blood group A and B antigens was confined to subjects of blood type A and B respectively, although three of nine type A specimens showed no lectin reactivity for group A antigen. Endothelial cells evidenced affinity for Ulex europeus I agglutinin demonstrative of fucose in all specimens. Mast cells disclosed lectin affinity consistent with the presence of terminal or internal mannose or N-acetylglucosamine residues. Two blood type O specimens were examined with conjugated lectins at the ultrastructural level. Secretory granules stained for content of terminal alpha-galactose, beta-galactose and fucose. These results support and concur with biochemical studies of complex carbohydrates in human cervical tissues. They reveal, in addition, the location of the blood group antigens in the human exocervix and endocervix and the marked heterogeneity among endocervical columnar cells in glycoprotein production.

Prostaglandins and their precursors can modify genetic damage-induced by gamma-radiation and benzo(a)pyrene

Experiments were performed to study the effect of various prostaglandins (PGs) and their precursors, gamma-linolenic acid (GLA) and arachidonic acid (AA) on gamma-radiation and benzo (a) pyrene (BP)-induced genetic damage to the bone marrow cells of mice, using the sensitive micronucleus (MN) test. Thromboxane B2 prostaglandin E1 and GLA completely prevented BP-induced and reduced to a great degree radiation-induced genetic damage, where as PGE2, PGF2 alpha and AA were without any effect. Since GLA and AA are widely distributed in the cell membranes, and as PGs can be formed virtually in response to any type of stimulus, it is likely that GLA and PGE1 may function as endogenous anti-mutagenic chemicals.

Lack of mutagenicity of irradiated glucose in Salmonella typhimurium using host-mediated assay

Experiments were conducted to study the ability of irradiated glucose to induce reverse mutations in S. typhimurium by host-mediated assay. The results revealed no significant increase in the frequency of reverse mutations compared to controls.

Histochemical examination of glycoconjugates of epithelial cells in the human fallopian tube

In human fallopian tubes, secretory cells made up about 70% and ciliated cells most of the remainder of the epithelium. At the light microscopic level, lectin-peroxidase conjugates and other methods demonstrated on secretory cells a surface glycocalyx containing glycoconjugates with fucose residues, terminal sialic acid-beta-galactose disaccharides, and sulfate esters. Secretory cells also expressed ABO blood group antigens, on their surface, staining for terminal alpha-N-acetylgalactosamine and alpha-galactose in blood group A and B subjects, respectively. The glycocalyx coating the cilia of all ciliated cells contained an acidic glycoconjugate with terminal sialic acid-beta-galactose disaccharides. Ciliated cells ranged from strongly positive to negative in staining for blood group ABO antigens, fucose, and terminal beta-galactose. The glycocalyx on the surface of cilia differed from that on the secretory cell surface in lacking sulfate esters and possessing terminal sialic acid-beta-galactose disaccharides cytochemically unlike those on secretory cells. Cytoplasmic granules, presumably secretory in nature, stained for blood group antigen in secretory cells of some specimens. Two lectin conjugates with affinity for the core region of N-glycosidically linked oligosaccharides revealed bodies interpreted as lysosomes in ciliated and secretory cells of most specimens. The latter lectins also stained mast cells intensely, presumably because of affinity for N-acetylglucosamine. The luminal surface of endothelial cells stained heavily for fucose and for a terminal sialic acid-beta-galactose disaccharide like that on the surface of cilia. The staining for carbohydrate did not vary qualitatively, and the ratio of secretory to ciliated cells did not differ with the phase of the menstrual cycle. The salpingeal epithelium in two patients with inactive endometrium did not differ from the others. The epithelium in a specimen from a patient with uterine fibroids showed foci of mucous metaplasia, containing a nonsulfated sialylated glycoconjugate. At the electron microscopic level, fucosylated glycoconjugate was visualized with a specific lectin conjugate on the surface of the secretory cells but not on the surface of ciliated and endothelial cells. Infrequent cytoplasmic granules containing mucosubstance apparently provided the cell mechanism in secretory cells for collecting and transporting material from biosynthetic sites to the glycocalyx.(ABSTRACT TRUNCATED AT 400 WORDS)

Prostaglandins and mutagenesis: prevention and/or reversibility of genetic damage induced by benzo (a) pyrene in the bone marrow cells of mice by prostaglandin E1

Prostaglandin E1 and thromboxane A2 (PGE1 and TXA2) have been proposed to bind to DNA, regulate gene action and prevent mutagenesis. Benzo (a) pyrene (BP) is a known mutagen and tumor promotor. BP-induced damage to the bone marrow cells of mice was prevented and/or reversed by PGE1 and by colchicine, an agent which may enhance PGE1 synthesis and TXA2 synthesis or action. PGF2 alpha did not have any action. Imidazole, a selective TXA2 synthesis inhibitor, enhanced the mutagenic action of benzo (a) pyrene. These results lend support to the concept that an altered PG system may have a role in the pathogenesis of mutagenesis and carcinogenesis.

Prostaglandins and mutagenesis: modification of phenytoin induced genetic damage by prostaglandins in lymphocyte cultures

Diphenylhydantoin (DPH) is known to cause genetic damage both in vivo and in vitro. We investigated the effect of prostaglandin E1, E2 and F2 alpha on DPH induced chromosomal aberrations in lymphocyte cultures in vitro. Prostaglandin E1 prevented and/or reversed DPH induced chromosomal aberrations, whereas PGE2 and PGF2 alpha were without inhibitory action. In fact, PGE2 and PGF2 alpha themselves induced genetic damage comparable to that of DPH, suggesting that PGE2 and PGF2 alpha are mutagenic in nature whereas PGE1 has anti-mutagenic properties. These results are consistent with the hypothesis that an altered prostaglandin system could be involved in mutagenesis.