Kinesin and Dynein Move a Peroxisome in Vivo: A Tug-of-War or Coordinated Movement?

We used fluorescence imaging with one nanometer accuracy (FIONA) to analyze organelle movement by conventional kinesin and cytoplasmic dynein in a cell. We located a green fluorescence protein (GFP)-tagged peroxisome in cultured Drosophila S2 cells to within 1.5 nanometers in 1.1 milliseconds, a 400-fold improvement in temporal resolution, sufficient to determine the average step size to be approximately 8 nanometers for both dynein and kinesin. Furthermore, we found that dynein and kinesin do not work against each other in vivo during peroxisome transport. Rather, multiple kinesins or multiple dyneins work together, producing up to 10 times the in vitro speed.

A systemic route for drug loading to lymphatic phagocytes

Lymph nodes are primary germination and proliferation sites for many types of pathogens. Maintaining therapeutic levels of appropriate chemotherapeutic agents in the lymph node tissue is critical for the treatment of both infection and cancer. This study was intended to develop a systemic route for loading lymph node phagocytes with drugs, using a lymph node specific nanocarrier. The latter is assembled as a 10-15 nm particle with a drug-carrying core and a phagocyte-homing poly(1-->6)-alpha-d-glucose based interface. Biokinetics and microdistribution of the model carrier were investigated in vivo. Nanocarrier accumulation in lymph nodes reached 30-35% dose/g in central lymph nodes, with deposition in various phagocytic cell populations. The latter included cells harboring inhaled microparticles translocated to lymph nodes from the lungs. In view of the nanocarrier ability to transport and release significant amounts of various drug substances, the data suggests feasibility of systemic drug loading to lymphatic phagocytes and, through drug release, to the neighboring cells.

Obstetric fistula: the challenge to human rights

Obstetric fistula can be explained to result from different causes. These holes in the tissue wall between the vagina and bladder and/or rectum are most prevalent in resource-poor countries, attributable to prolonged obstructed labour and absent or inaccessible remedial prenatal services. Obstructed labour is often due to small pelvic size, resulting from women's youth and premature childbearing and/or malnutrition. Poverty at national health-service and family levels often predisposes pregnant populations to suffer high rates of fistula. Global estimates showing up to 100,000 new cases each year and 2 million affected girls and women are probably gross underestimates. Fistula devastates lives of sufferers, who are often expelled by husbands and become isolated from their families and communities. Failures of states to provide prenatal preventive care (including medically indicated cesarean deliveries) and timely fistula repair violate women's internationally recognized human rights, especially to healthcare in general and reproductive healthcare in particular.

Synthesis of a Macromolecular Camptothecin Conjugate with Dual Phase Drug Release

A water soluble macromolecular conjugate of camptothecin (CPT) with a new, dual phase hydrolytic drug release mechanism was prepared on the basis of a 60 kDa biodegradable hydrophilic "stealth" polyacetal, poly(1-hydroxymethylethylene hydroxy-methyl formal). Succinamido-glycinate was used as a prodrug releasing group. A model preparation with 7.5% CPT content w/w was water soluble. The lipophilic camptothecin prodrug, camptothecin-(O20)-succinimidoglycinate, was released from the conjugate with t(1/2) = 2.2 +/- 0.1 h in rodent plasma. The blood clearance in a rodent model as measured by CPT was release limited, t(1/2) = 2.1 +/- 0.2 h, while the conjugate half-life was 14.2 +/- 1.7 h. In a xenograft tumor model, the conjugate demonstrated higher antineoplastic efficacy than CPT at a less than equitoxic dose. This improved therapeutic window is in line with the modified drug pharmacokinetics and with camptothecin release in a stabilized lipophilic prodrug form. Regulation of prodrug release and hydrolysis rates through linker structure modification will open the way to further improve both pharmacokinetics and pharmacodynamics.

Cutaneous haemangioma: prevalence and sonographic characteristics of associated hepatic haemangioma

AIMS

To determine the prevalence of hepatic haemangiomas (HH) occurring with multiple or large cutaneous haemangiomas (CH), and compare the ultrasound (US) characteristics of HH with morphology of concurrent CH.

MATERIALS AND METHODS

Retrospective and prospective sonographic and clinical analysis was undertaken on 69 patients referred for US to exclude silent HH. This comprised 62 patients referred over 6 years with six or more CH or one large CH (#10878;5 cm) and seven patients referred over 1 year with three to five small CH.

RESULTS

HH occurred in 45% miliary CH and 40% mixed small and large CH, but also in 12-14% of patients with one large or three or more small CH. None had HH progression. There was association between HH sonographic characteristics and CH number and morphology.

CONCLUSION

Clinically silent HH occurred in nearly one in four of infants presenting overall with six or more small CH or large CH. Previous studies have documented HH mortality between 18 and 80%, although this was not shown in our study. Therefore, if clinical suspicion exists, US is indicated to enable early steroid treatment if significant HH are present.

Hormone replacement therapy menopause with a better future--a survey of views on hormone replacement therapy (HRT)

OBJECTIVE

To assess the views and prescribing practices of doctors regarding hormone replacement therapy (HRT).

METHODS

In April 1999, 103 doctors from a teaching hospital participated in a survey. Using a self-administered questionnaire, subjects were contacted at the departments of Internal Medicine, Family Medicine, Obstetrics and Gynaecology, and Orthopaedics.

RESULTS

Seventy-two percent were below 40 years of age and 67% of the respondents were male. Most doctors believed that HRT decreases the risk of subsequent osteoporosis (97%), ischaemic heart disease (77%) and depression associated with menopause (64%). Doctors generally considered menopausal symptoms (90%), premature menopause (87%), surgical menopause (85%) and osteoporotic fracture (77%) as clear indications for hormone replacement therapy. Absolute contraindications to the therapy were stated as recent breast cancer (82%) and recent endometrial cancer (84%). Among the specialities covered, there were differing views on proposed duration of HRT. It was generally believed that a pelvic examination, cervical smear and mammography were pre-requisites when initiating and monitoring HRT. Majority (69%) felt that HRT should be offered to all menopausal women, assuming no contraindications and most (73%) did discuss HRT with their patients. However, less than 10% of the menopausal patients under their care were using HRT. Those doctors not in favor of universal offering of HRT (31%) considered unreliable patient follow up to be the main reason. Females were two times more likely to discuss HRT with their patients (p = .08). Doctors who discussed HRT with their patients were four times more likely to consider HRT for themselves or their spouses (p = .13). Gynecologists were eight times more likely to prescribe HRT than non-gynecologists (p = .001).

CONCLUSION

Doctors are positively disposed to the universal offering, and use of HRT. Further studies are needed to understand a possible gap between perceived and actual prescribing practice.

Thoracic splenosis diagnosed by fine-needle aspiration cytology: a case report

A case of thoracic splenosis diagnosed by fine-needle aspiration (FNA) of subpleural lung lesions is presented. The patient, a 49-yr-old male with a history of gunshot wound to his trunk with splenic rupture and splenectomy several years previously, presented with recent hemoptysis and multiple subpleural solid nodules shown in the left lung field by CT scan. As the possibility of a metastatic malignancy vs. mesothelioma was entertained, an FNA was performed on one of these lesions, revealing lymphoid tissue with abundant vascularity simulating the structure of splenic tissue. In view of this finding, supported by the absence of splenic outline in the CT radiograph, the diagnosis of splenosis was made. This is the fourth reported case of thoracic splenosis in which FNA cytology was utilized for diagnosis, yet the first in which the diagnosis was based exclusively on the FNA cytologic findings. Clinical, pathologic, and diagnostic aspects of this entity are discussed.

Prolonged in vivo anticoagulant activity of a hirudin-albumin fusion protein secreted from Pichia pastoris

Hirudin is a small, proteinaceous thrombin inhibitor that clears rapidly from the circulation. A hexahistidine-tagged hirudin-rabbit serum albumin (RSA) fusion protein, HLAH6, was characterized following secretion from Pichia pastoris. HLAH6 bound to immobilized nickel, anti-RSA, and anti-hexahistidine antibodies, and contained the expected (ITYTD) N-terminus. Its spectrometric mass was 74,490 (versus the theoretical mass of 74,410 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobility of 84 kDa). The terminal catabolic half-life in rabbits of HLAH6, recombinant Pichia-derived His-tagged RSA, or plasma-derived RSA did not differ. Injection of 2 mg/kg HLAH6 into rabbits raised the activated partial thromboplastin time (aPTT) above initial values for 4-24 h, while the equimolar dose of unfused hirudin was without significant effect. A higher dose of HLAH6 (3 mg/kg functional HLAH6, equivalent to 37.6 thrombin-inhibitory units/g) raised the aPTT by 2.0- to 2.5-fold; the elevation persisted for > 48 h. Importantly, both HLAH6 and unfused hirudin inhibited clot-bound thrombin. Our results suggest that HLAH6 exhibits not only delayed clearance, but also prolonged biological activity in vivo compared with unfused hirudin.

Behind the counter: pharmacies and dispensing patterns of pharmacy attendants in Karachi

BACKGROUND

There is little literature available on dispensing patterns and unsupervised sale of medicines from pharmacies in developing countries.

OBJECTIVE

This study obtained background information on pharmacies, assessed the level of training, knowledge and dispensing patterns of pharmacy attendants in Karachi.

METHODOLOGY

This is a descriptive cross sectional study with convenient sampling. A structured questionnaire was used to interview pharmacy attendants.

RESULTS

Of the 219 pharmacies surveyed, 62% reported more than 50 customers daily and 20% also sold items of general provision. Mean operating hours were 13. Only 24 (11%) had a visible license. On an average 3 attendants were employed per pharmacy. We interviewed one in each. Amongst the 219 interviewed, 77 (35%) were intermediate qualified and only 26 (12%) pharmacologically trained. Correct frequency of ORS administration was not known by 167 (76%) and 21% incorrectly suggested an anti-diarrhoeal preparation for viral diarrhoea in children. The knowledge of those with pharmacological training was significantly better. For respiratory tract infection in children approximately 60% did not know the correct dose of Paracetamol and Amoxicillin. Only 13 (6%) knew that Propanalol was contraindicated in hypertensive asthamatics. For Cotrimoxazole, metronidazole and lomotil only 40%, 21% and 15% respectively, were aware that these could not be dispensed without prescription.

CONCLUSION

In the absence of trained pharmacists existing pharmacy attendants should be trained to improve drug-dispensing patterns.