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Biomedical subjects

J I Blenkharn

Publications and source records attributed to J I Blenkharn.

At least 19 recordsLinked to original sources

Potential compromise of hospital hygiene by clinical waste carts.

Bulk waste storage carts are common in hospitals and undoubtedly assist in the day-to-day management of clinical wastes. They are used for the transport and interim storage of primary clinical waste containers and are often located close to or within hospital buildings to receive such wastes from clinical departments. Examination of a random selection of bulk clinical waste carts at nine acute hospitals across Greater London revealed external soiling in all of 23 carts. Eight of 13 carts were also soiled on the inner surfaces, with evidence of bloodstains and free fluids in the base of five carts. Staphylococcus aureus and enterococci were recovered in low numbers from the lids (N=7) and wheels (N=10) of carts and Escherichia coli, Enterobacter spp. and Pseudomonas aeruginosa were recovered from the wheels of a further five carts. Two carts were heavily contaminated with Aspergillus spp. Pathogens originating from clinical wastes may be transferred from contaminated bulk waste carts to the wider hospital environment. It may be advisable to keep bulk carts outside clinical areas, and preferably outside all hospital buildings. This becomes particularly important in circumstances where carts supplied by contractors are not dedicated to a single hospital or National Health Service trust.

Blood-Borne Pathogens↗

Lowering standards of clinical waste management: do the hazardous waste regulations conflict with the CDC's universal/standard precautions?

Clinical waste is a costly and troublesome commodity. Comprising the detritus of medical care, the foremost hazard is the risk of infection from micro-organisms present in these wastes. Infection commonly occurs through penetrating injury, the so-called 'sharps' or 'needlestick' injury, although contamination of non-intact skin or splashes to the eye may transmit infection. Bloodborne viruses (hepatitis B, hepatitis C, human immunodeficiency virus) are the most serious threat, although respiratory, soft tissue and enteric infections are not unknown. The European Hazardous Waste Directive, that harmonizes the categorization and control of wastes, permits downregulation of clinical wastes where the risk of infection may be low. Although strengthened by the requirement for risk assessment in waste classification, UK regulatory guidance promoting classification of some clinical wastes as non-hazardous completely ignores the Centers for Disease Control and Prevention's Universal Precautions for the prevention of transmission of human immunodeficiency virus, hepatitis B virus and other bloodborne pathogens in healthcare settings, which seek to prevent bloodborne virus infection in healthcare workers and others, and the more extensive Standard Precautions that extend these principles to the prevention of healthcare-associated infections and the environmental spread of nosocomial pathogens. By creating a potent cost driver encouraging downregulation of some clinical wastes, UK legislation based on the European Hazardous Waste Directive conflicts with the CDC's Universal/Standard Precautions.

Animals↗

Standards of clinical waste management in UK hospitals.

The arrangements for bulk clinical waste handling were observed in 26 UK hospitals. Storage of waste carts in areas freely accessible to the public, and failure to lock individual carts was common. Many clinical waste carts and areas dedicated to their storage were in a poor state of repair. Substantial improvement is required in the management of clinical waste in hospitals in order: (1) to eliminate the possibility of acquired infection through unauthorized, inappropriate access to clinical waste and to minimize adverse effects resulting from contact with waste pharmaceuticals; (2) to comply with the Duty of Care imposed by UK Health & Safety legislation; and (3) to satisfy concerns regarding the general standard of hospital hygiene.

Cross Infection↗

Medical wastes management in the south of Brazil.

Medical (clinical) wastes are costly in disposal and carry risks of infection, or physical injury, and of exposure to potentially harmful pharmaceuticals, as well as being aesthetically unacceptable. Technological advances in disposal, together with the introduction of rigorous emission standards for incinerators and similarly stringent control standards for non-burn "alternate" disposal technologies, continue to drive improvements in waste management. Are these improvements attainable in developing countries? Where adequate resources and a robust infrastructure are lacking, investment in advanced disposal technologies may be counterproductive. Developments must be appropriate to and manageable by the communities served; sustainable low-technology approaches may be preferable. There remains a need for affordable technical innovation, as well as underlying political support and international financial and technical assistance, to sustain meaningful improvements in waste management in remote and isolated regions and more generally in developing countries.

Brazil↗

The disposal of clinical wastes.

The disposal of clinical wastes is often poorly conducted and inadequately supervised despite the publication of clear and definitive working guidelines and the introduction of increasingly stringent legislative control. The move away from landfill disposal of clinical wastes, and the further development of high temperature incinerators able to meet increasingly tight emission limits, is to be applauded but has inevitably increased the cost of waste disposal. Moreover, such developments fail to address the continuing 'shop floor' problems whereby wastes enter an inappropriate waste stream or colour coded wastes containers are used for inappropriate purposes thus undermining the value of a nationally approved hazard warning policy. The development of newer waste treatments, including microwave exposure of macerated wastes, may reduce costs and aid in the control of environmental pollution. However, stringent control of this and existing technologies remains essential. Additionally, increasing resources must be directed to improvements in primary waste disposal practices whereby all health care staff have a clear responsibility to ensure correct disposal of wastes without risk to themselves, their colleagues and others, or to the environment.

Bacteria↗

Pathologic and hemodynamic sequelae of unilobar biliary obstruction and associated liver atrophy.

A patient is presented with unilobar biliary obstruction associated with marked liver atrophy and compensatory hypertrophy. Characteristically she was not jaundiced and had no portal hypertension. Quantitative measurements of the degree of hepatocyte hyperplasia showed that over 50% of cells in the hypertrophied lobe were hyperplastic. Surprisingly, a similar percentage of cells in the atrophied lobe were also hyperplastic. No difference was found in the size of hepatocytes between the two lobes or among the hepatocyte subpopulations in the atrophied lobe. The findings in this case suggest (1) lobar atrophy induces a hyperplastic response in more than one half of the cells of the contralateral lobe; (2) the development of atrophy consequent on biliary obstruction is likely the result of destruction of whole cells rather than cytoplasmic loss; (3) the development of a hyperplastic response within the atrophied lobe is a new finding and is consistent with the hormonal theory of hepatic regeneration; and (4) striking compensatory hypertrophy of the liver is associated with normal portal venous pressure.

Atrophy↗

Prevention of transmission of infection during mouth-to-mouth resuscitation.

The risk of infection transmitted during mouth-to-mouth or mouth-to-nose resuscitation procedures is difficult to define but is possibly quite low. However, the perceived risk is sufficient to cause serious concern for many individuals, including trained hospital personnel as well as the general public, and may preclude prompt and effective action. A novel airway device was evaluated for the retention of infective droplets and fluid permeability under simulated resuscitation conditions using a cardiopulmonary resuscitation training manikin. Retention of a 0.5-5.0 micron aerosol of Staphylococcus aureus cells was greater than 80% at flow rates of 6 l/min while under simulated resuscitation conditions the trapping of bacteria, originating predominantly from saliva, was over 90%. These data suggest that this device may afford significant protection against transmission of infection during exhaled air resuscitation manoeuvres.

Bacterial Infections↗

In-vitro antibacterial activity of noxythiolin and taurolidine.

The minimum inhibitory concentrations (MIC) of noxythiolin and taurolidine were determined for strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Tests were performed in broth alone and in broth plus 25% v/v serum or 25% v/v urine. Inoculum density was either 10(3), 10(5) or 10(7) colony forming units per mL-1. Slight inoculum-dependent variation in the activity of both agents was observed for some, but not all, strains of P. aeruginosa and S. aureus. A more pronounced medium-dependent increase in activity was observed with both drugs, with up to 8-fold reduction of values for MIC when tested in the presence of serum or urine. These observations may help to clarify the disparity between the observed clinical efficacy of these agents and relatively poor in-vitro activity when tested using conventional methods in synthetic media.

Drug Evaluation, Preclinical↗

Outcome of radical surgery in hilar cholangiocarcinoma.

In a prospective study performed between 1977 and 1985, 27 patients with cholangiocarcinoma at the confluence of the hepatic ducts underwent resection aiming at cure. Eleven patients underwent local excision and 16 underwent partial liver resection (extended right hepatic lobectomy in 12, left hepatic lobectomy in 3, and extended left hepatic lobectomy in 1). The 60-day hospital mortality rate was 7.4% (2 patients). None of 11 patients who underwent local excision and only 1 (5.5%) of 18 patients who had not undergone previous surgery, or preoperative biliary drainage, died in the hospital. The overall median and mean survival times for the 24 patients who left the hospital were 25 and 29 months, respectively (range, 5 to 80 months). Twenty patients died after a median survival of 22 months (mean, 25 months; range, 5 to 80 months). Four patients are alive and well at 45, 48, 51, and 54 months. Estimated (Kaplan-Meier) survival rates for all 27 patients at 1, 3, and 5 years were 70%, 26%, and 22%, respectively, with almost all patients dying of persistent or recurrent local disease. Survival time after hepatic resection was not statistically different from that after local excision of the lesion (p greater than 0.1). The difference in survival times between patients with histologic clearance and those with microscopically positive or close (less than 1 mm) resection margins was marginally significant statistically (p = 0.037). The quality of life was good. These results are in agreement with those of other studies employing treatment by excision and emphasize the need to assess all patients with hilar cholangiocarcinoma with a view to resection before the adoption of surgical bypass or palliative intubational procedures. However, further progress is unlikely to be made without significant advances in adjuvant therapy.

Adenoma, Bile Duct↗

Patterns of serum alkaline phosphatase activity in unilateral hepatic duct obstruction: a clinical and experimental study.

The levels of serum alkaline phosphatase (ALP) were measured in eight patients with bile duct obstruction limited to one lobe of the liver. Although an initial rise of enzyme concentration was documented in every patient, unrelieved biliary obstruction was associated with a gradual return of ALP to normal values. The return to normal levels coincided with the development of atrophy of that part of the liver deprived of its bile drainage. An animal model of experimental selective biliary obstruction supported a causative association between reduction of hepatocyte mass and a decrease in ALP activity. It appears that normal serum ALP levels can be expected with advanced obstructive biliary disease. Suspected lobar or segmental duct obstruction warrants investigation--even if liver function tests are normal.

Adult↗