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Biomedical subjects

A Trehan

Publications and source records attributed to A Trehan.

At least 19 recordsLinked to original sources
PubMed2005

Biodegradable microspheres for parenteral delivery.

Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery.

Biodegradation, Environmental↗
PubMed2004

Poly-epsilon-caprolactone microspheres and nanospheres: an overview.

Poly-epsilon-caprolactone (PCL) is a biodegradable, biocompatible and semicrystalline polymer having a very low glass transition temperature. Due to its slow degradation, PCL is ideally suitable for long-term delivery extending over a period of more than one year. This has led to its application in the preparation of different delivery systems in the form of microspheres, nanospheres and implants. Various categories of drugs have been encapsulated in PCL for targeted drug delivery and for controlled drug release. Microspheres of PCL either alone or of PCL copolymers have been prepared to obtain the drug release characteristics. This article reviews the advancements made in PCL-based microspheres and nanospheres with special reference to the method of preparation of these and their suitability in developing effective delivery systems.

Animals↗
PubMed2004

Undifferentiated embryonal sarcoma in children: beware of the solitary liver cyst.

Undifferentiated embryonal sarcoma (UES) of liver is a rare form of liver tumor in children. It may have an atypical presentation leading to delay in diagnosis. The authors report on 3 consecutive children with this condition, each of them presenting in older children who presented with this condition and an initial diagnostic dilemma. One of them presented initially with a solitary cyst, the second with severe abdominal pain, and the third with intermittent fever. Preoperative chemotherapy was successful in shrinking the tumors in 2 children to allow anatomic liver resection with tumor-free margin. Both remain free of recurrence 2 years after completing treatment.

Abdominal Pain↗
PubMed2004

Visceral leishmaniasis in a non-endemic area of India.

The study included 57 patients with visceral leishmaniasis. The average duration of symptoms was 3.8 +/- 3.55 months and pancytopenia was the commonest haematological abnormality. The parasite load directly correlated with the degree of anaemia at presentation (P=0.03). Splenic regression took 9.58 +/- 4.5 days and haematological parameters recovered in 14.5 +/- 9.07 days. There were five deaths over the five-year study duration. Leishmaniasis was not the first diagnosis in 14 patients, of whom eight were residents of non-endemic regions. Diagnosis was achieved in 13.5 days in these patients, compared to 4.5 days in patients where leishmaniasis was suspected at the outset.

Adult↗
PubMed2004

Radioactive microspheres in therapeutics.

Microspheres as a drug delivery system hold great promise in reaching the goal of controlled drug delivery as well as site specific delivery. In the last few decades, scientific and technological advancements have been made in the research and development of radiolabeled microspheres. These are used successfully for the treatment of various cancers and tumors. Since response to chemotherapy and external radiotherapy is not so effective and hazardous too, so an alternative to this is internal radiation therapy. These radiolabeled microspheres are very stable and have a proven efficacy in the field of primary as well as metastatic cancers. Radioactive microspheres can be selectively targeted to various tumors without undue radiation to the nontumorous tissues. The radioactive microspheres are injected to halt tumor growth via the blood supply, thereby enabling surgical removal once the tumor size decreases. This review provides an outlook to various aspects of radioactive microspheres and their role in treatment of various tumors and cancers.

Albumins↗
PubMed2003

End-stage renal disease in Indo-Asians in the North-West of England.

BACKGROUND: The incidence of end-stage renal disease (ESRD) in England is increasing. There is a higher incidence of ESRD in British Indo-Asians than in the White population. AIM: To determine to what degree the increasing demand for renal replacement therapy in the UK is due to Indo-Asian patients. To study the presentation to renal services of Indo-Asian patients with ESRD and report any inequalities in initial treatment of Indo-Asian patients with ESRD compared to their White counterparts. DESIGN: Prospective, inception cohort study. METHODS: Consecutive adult patients with ESRD who started renal replacement therapy between 1 April 2000 and 31 December 2001 in all 14 renal units serving an area from North Cheshire to South Cumbria, including Greater Manchester and Lancashire, were recruited and interviewed. RESULTS: Of the 578 patients, 9.5% were Indo-Asian. The annual acceptance rate for renal replacement therapy was 342 per million population in Indo-Asians, compared with 91 per million population in the White population ( p < 0.001). Indo-Asian patients with ESRD were younger (median age 51 years vs. 60 yrs, p = 0.006) and more socially deprived (81% vs. 36.5% in the 5th Carstairs quintile, p < 0.001). A greater proportion of Indo-Asian patients with ESRD presented late to specialist renal services (31% vs. 19%, p = 0.03). Once adjusting for their younger age, atherosclerotic renovascular disease and/or hypertensive nephropathy was more prevalent in Indo-Asian patients (OR 4.9; p = 0.03). There was no difference in the initial mode of maintenance dialysis or the perception of choice the patients felt they had, based on their ethnicity. DISCUSSION: There is a silent epidemic of ESRD in Indo-Asian patients in the North-West, possibly vascular in aetiology, in which specialist intervention is late. This suggests that Indo-Asian patients should be prioritized for early intervention strategies to reduce the burden of ESRD.

Age Distribution↗
PubMed2003

Diagnostic microspheres: an overview.

Diagnostic methods have become increasingly complex and frequently involve the use of agents that must meet the same approval criteria as drugs. The search for diagnostic contrast agents has spread from X-ray to other imaging modalities, especially to magnetic resonance imaging (MRI) and ultrasound. A wide variety of methods have been used to develop microencapsulated agents, from liposomal entrapment to use of biodegradable polymers. Various scientific and technological advancements have been made in the research and development of diagnostic microspheres. Diagnostic microspheres can be used to understand the human body functions in both healthy and sick people. For example, they allow the detection of malignancies vs. benign tissue changes. Diagnostic microspheres give useful clinical information for various diseases, are very stable, and have proven efficacy in the quantitative measurement of blood flow to an organ. This review discusses various aspects of diagnostic microspheres, such as the choice of contrast agents and radioactive molecules, and their applications in blood flow measurements and organ imaging.

Animals↗
PubMed2003

Needle necropsy in AIDS.

The value of autopsy in understanding the natural course of any disease is beyond any argument. The reluctance of pathologists to perform autopsy in HIV infected cadavers is justified due to the risks involved to the prosector and the morgue attendants. A relative low risk needle necropsy protocol is proposed using fine needle aspiration cytology, tru-cut biopsies and microbiological examination. Diagnosis could be offered in all the forty-four needle necropsies performed. Disseminated tuberculosis in 18/44 (40.9%) cases, disseminated cryptococcosis in 12/44 (27.2%) cases, poly-microbial infections in 27.2% cases and non-Hodgkin's lymphoma in 9% cases were detected in the study. Infectious agents like Histoplasma capsulatum, Isospora belli, tachyzoites of Toxoplasma gondii, Candida sp and Cryptococcus sp could be demonstrated in the samples obtained in the study. Lack of material for study of gross pathology, inaccessibility of deep-seated lesions and risk of needle stick injury to the prosector though low are the limitations of this procedure.

AIDS-Related Opportunistic Infections↗
PubMed2002

Generalized lymphadenopathy caused by Trichosporon asahii in a patient with Job's syndrome.

Of the six species of Trichosporon known to cause human infections, T. asahii is the main agent of invasive trichosporonosis. We describe an unusual case of generalized lymphadenopathy due to T, asahii in a 10-year-old boy with Job's syndrome (markedly elevated IgE with eosinophilia). The diagnosis was based on the presence of blastic conidia and hyphal elements breaking into arthroconidia in biopsied tissue of the cervical lymph node and isolation of the causal agent T, asahii in pure culture. The patient responded initially to amphotericin B therapy, but the infection recurred within 4 weeks and did not respond to therapy of liposomal amphotericin B and 5-fluorocytosine for 10 days. The patient left the hospital against medical advice.

Child↗
PubMed2001

Leucocytoclastic vasculitis in infant.

Acute hemorrhagic edema of infancy is a laucocytoclastic vasculitis characterized by a triad of fever, large purpuric skin lesions and edema. The presentation is often dramatic. The manifestations are often misinterpreted as a septicemic illness. We report the occurrence of this syndrome in a 1 1/2-year-old-child, highlighting some of the diagnostic and therapeutic problems encountered.

Humans↗
PubMed2001

Ptosis in late infantile Tay-Sachs disease.

The brief communication describes a 2-year-old child who presented with delayed achievement and regression of milestones, seizures of multiple types, exaggerated response to sound, inability to see and bilateral cherry red spots. In addition to these typical manifestations of the late infantile variety of Tay-sachs disease, unilateral ptosis was present. The magnetic resonance imaging of brain revealed abnormalities consistent with an advanced stage of the disease.

Basal Ganglia↗
PubMed2000

Partial nephrectomy in cystic partially differentiated nephroblastoma.

Cystic partially differentiated nephroblastoma (CPDN) is an uncommon renal neoplasm in children. It is now recognized as a tumor with low but definite malignant potential. The authors report a patient that was treated with partial nephrectomy and chemotherapy with successful outcome. The literature on CPDN is briefly discussed.

Humans↗