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Biomedical subjects

M Kane

Publications and source records attributed to M Kane.

At least 37 records · Page 2Linked to original sources
PubMed1999

Transmission of hepatitis B, hepatitis C and human immunodeficiency viruses through unsafe injections in the developing world: model-based regional estimates.

Thousands of millions of injections are delivered every year in developing countries, many of them unsafe, and the transmission of certain bloodborne pathogens via this route is thought to be a major public health problem. In this article we report global and regional estimates of the number of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections that may occur from unsafe injections in the developing world. The estimates were determined using quantitative data on unsafe injection practices, transmission efficiency and disease burden of HBV, HCV and HIV and the prevalence of injection use obtained from a review of the literature. A simple mass-action model was used consisting of a generalized linear equation with variables accounting for the prevalence of a pathogen in a population, susceptibility of a population, transmission efficiency of the pathogen, proportion of injections that are unsafe, and the number of injections received. The model was applied to world census data to generate conservative estimates of incidence of transmission of bloodborne pathogens that may be attributable to unsafe injections. The model suggests that approximately 8-16 million HBV, 2.3-4.7 million HCV and 80,000-160,000 HIV infections may result every year from unsafe injections. The estimated range for HBV infections is in accordance with several epidemiological studies that attributed at least 20% of all new HBV infections to unsafe injections in developing countries. Our results suggest that unsafe injections may lead to a high number of infections with bloodborne pathogens. A major initiative is therefore needed to improve injection safety and decrease injection overuse in many countries.

Cross Infection↗
PubMed1998

Forces required to initiate sliding in second-generation intramedullary nails.

Second-generation intramedullary nails, which allow the fixation screw that is placed in the femoral head to slide distally and thus allow compression of the fracture of the femoral neck, have become a popular option for the treatment of ipsilateral fractures of the femoral neck and shaft. However, the sliding characteristics of the screw within the barrel of the nail or the side-plate have not been assessed biomechanically, to our knowledge. The goal of the current study was to investigate the forces required to initiate sliding of the proximal screw in intramedullary devices and to compare these forces with those required to initiate sliding of hip screws. The loading configuration simulated the typical angle of 135 degrees between the intramedullary nail and the proximal screw. The forces required to initiate sliding of the proximal screw, with the screw extended fifty-one, seventy-six, eighty-six, and 102 millimeters beyond the proximal end of the barrel, were measured for three different types of second-generation intramedullary nails (Recon, ZMS, and Gamma), a sliding compression hip screw, and an intramedullary hip screw, and these forces were then compared. With each amount of extension of the screw, the hip screws required lower forces to initiate sliding than did the second-generation intramedullary devices. Of the second-generation devices, the Gamma nail required the highest forces to initiate sliding; the Recon and ZMS nails required 20 to 40 percent lower forces compared with the Gamma nail. None of the devices jammed in any of the loading configurations that were tested. When the extension of the screw was increased, higher forces were required to initiate sliding.

Biomechanical Phenomena↗
PubMed1998

Unsafe injections.

In many developing countries use of unsterilized or improperly sterilized needles and syringes is common and causes millions of cases of viral hepatitis B and C as well as contributing to the spread of human immunodeficiency virus (HIV) and other bloodborne pathogens. To combat this problem, WHO has stimulated the development of the "auto-destruct" syringe and encourages all donors, international agencies, and health departments to include a supply of such syringes with all vaccines supplied for emergency purposes. In addition, health providers and the public need to be educated about the risk of inappropriate and unsterile injections.

Blood-Borne Pathogens↗
PubMed1997

Integration of hepatitis B vaccination into national immunisation programmes. Viral Hepatitis Prevention Board.

Hepatitis B is a major public health problem even though safe and effective vaccines have been available for over 10 years. Because hepatitis B infection is largely asymptomatic with long term complications occurring after many years it has not received the attention it deserves. Strategies to immunise those at high risk have failed to control the disease. Delegates to the World Health Assembly of the World Health Organisation recommended in May 1992 that all countries should integrate hepatitis B vaccination into their national immunisation programmes by 1997. Some western European countries remain unconvinced that the burden of disease warrants the expense of universal vaccination. However, epidemiological data and economic evaluation show that universal hepatitis B vaccination is cost effective in countries with low endemicity and that it will control hepatitis B, reinforcing the necessity for action.

Cost-Benefit Analysis↗
PubMed1997

Mechanical, acoustic and electromagnetic evaluation of the semi-implantable middle ear hearing device (SIMEHD).

The properties of the partially implantable middle ear hearing device (SIMEHD) were extensively studied. The internal unit was subjected to 5,000 cycles of bending at a force of 75 g (gravity) without failure. An accurate measurement of the force output of the SIMEHD was obtained (14-25 dynes/mA). This force is too small to cause any damage to the ossicular chain. The force resulting from electromagnetic interference over a wide frequency range (500 khz -1 Giga (10(9)) Hz) was measured and noted to be within the margin of safety. The frequency response plots (500-8,000 Hz) were also obtained and revealed an excellent ability to amplify middle and high-frequency sounds.

Acoustics↗
PubMed1997

Semi-implantable middle ear electromagnetic hearing device for sensorineural hearing loss.

A semi-implantable middle ear electromagnetic hearing device (SIMEHD) is proposed for limited clinical trial in adult patients to evaluate the implantable hearing device for moderate to severe sensorineural hearing loss. Food and Drug Administration (FDA) investigational device exemption (IDE) approval has been granted (May 1996) for clinical trials. The implant unit has been evaluated acutely and chronically in animals (cats) with excellent results. Five cats undergoing chronic implantation were allowed to survive an average of 9.6 months, showing that the SIMEHD is biocompatible, functional and without untoward complications. All implant units recovered from the cats were functional, except for wire breakage of the internal antenna. A new antenna was redesigned for human implantation. The SIMEHD system consists of an external and internal unit. The external unit consists of a microphone, audio amplifier, modulator, radio frequency (RF) amplifier, antenna and battery. The internal unit is composed of a receiving antenna, hybrid electronic circuit, air core driving coil, and a target magnet cemented to the incus. All materials in contact with the body are biocompatible and expected to survive indefinitely. The implant unit is miniaturized and manufactured with existing fabrication technology by our industrial collaborator, Wilson Greatbatch, Ltd. The specific aims and major tasks of the proposed research are: a) to evaluate reliability, safety and efficacy of the SIMEHD system in a selected group of patients diagnosed with sensorineural hearing loss, due mainly to presbycusis or aging of the inner ear; and b) to obtain objective and subjective evaluation of audiologic and psychoacoustic performance as compared to the acoustic hearing aid. This paper describes the design, illustrates the actual device (newest prototype) and details the technique for surgical implantation in the attic and mastoid antrum in humans.

Adult↗
PubMed1997

External unit for a semi-implantable middle ear hearing device.

A miniaturized, low-power external unit has been developed for the clinical trials of a semi-implantable middle ear electromagnetic hearing device (SIMEHD) which uses radio-frequency telemetry to couple sound signals to the internal unit. The external unit is based on a commercial hearing aid which provides proven audio amplification and compression. Its receiver is replaced by an application-specific integrated circuit (ASIC) which: 1) adjusts the direct-current bias of the audio input according to its peak value; 2) converts the audio signal to a one-bit digital form using sigma-delta modulation; 3) modulates the sigma-delta output with a radio-frequency (RF) oscillator; and 4) drives the external RF coil and tuning capacitor using a field-effect transistor operated in class D. The external unit functions as expected and has been used to operate bench-top tests to the SIMEHD. Measured current consumption is 1.65-2.15 mA, which projects to a battery lifetime of about 15 days. Bandwidth is 6 kHz and harmonic distortion is about 2%.

Ear, Middle↗
PubMed1996

Meiotic pachytene arrest in MLH1-deficient mice.

Germ line mutations in DNA mismatch repair genes including MLH1 cause hereditary nonpolyposis colon cancer. To understand the role of MLH1 in normal growth and development, we generated mice that have a null mutation of this gene. Mice homozygous for this mutation show a replication error phenotype, and extracts of these cells are deficient in mismatch repair activity. Homozygous mutant males show normal mating behavior but have no detectable mature sperm. Examination of meiosis in these males reveals that the cells enter meiotic prophase and arrest at pachytene. Homozygous mutant females have normal estrous cycles and reproductive and mating behavior but are infertile. The phenotypes of the mlh1 mutant mice are distinct from those deficient in msh2 and pms2. The different phenotypes of the three types of mutant mice suggest that these three genes may have independent functions in mammalian meiosis.

Adaptor Proteins, Signal Transducing↗
PubMed1996

The detection of picoplankton 16S rDNA in cases of drowning.

Picoplankton belonging to the Synechococcus genus in cyanobacteria (approximately 1 micron in size) are found ubiquitously in Lake Biwa, Japan. However, they could not be morphologically discriminated from other bacteria by microscopy. In this study we attempted to use picoplankton for the diagnosis of drowning by PCR analysis of the 16S ribosomal DNA (rDNA). We designed primers complementary to the variable regions of 16S rDNA of the picoplankton we had sequenced. A comparison was made of the PCR products from the three picoplanktons, five other cyanobacteria, Melosira (diatom), Staurdstrum (green alga), bacteria from Lake Baikal, and humans. The picogram order of template DNA from picoplankton was specifically amplified by the primers. When the template of picoplankton was mixed with human lung tissue, at least 10 ng of template DNA was needed to obtain a PCR product. The isolation of the picoplankton from human lung tissue increased the sensitivity of PCR more than a hundred-fold. The specific PCR products of the picoplankton were obtained from formalin-fixed drowning tissue. Molecular biological diagnosis of drowning was successful using picoplankton 16S rDNA.

Animals↗