Biomedical subjects

D M Allen

Publications and source records attributed to D M Allen.

At least 19 recordsLinked to original sources

PubMed1998

Outcomes after severe trauma at a northern Canadian regional trauma centre.

OBJECTIVE: To evaluate outcomes of trauma patients at a northern community trauma referral centre that does not meet several of the guidelines for a trauma centre. DESIGN: A retrospective study. SETTING: Sudbury General Hospital in northern Ontario. PARTICIPANTS: All trauma patients admitted between 1991 and 1994 who had an Injury Severity Score (ISS) greater than 12. OUTCOME MEASURES: Actual survival to discharge was compared to survival predicted by TRISS analysis. Z, W and M scores were calculated by standard TRISS techniques. RESULTS: Of 526 patients with an ISS greater than 12, 416 (79%) were suitable for TRISS analysis. Of these 416 patients, 310 (74%) were men. The mean age was 39 years. Two hundred and sixty-one (63%) patients were admitted directly to the Sudbury General Hospital, whereas 155 (37%) were transferred from other hospitals. The leading causes of injury were motor vehicle-traffic accidents in 48%, motor vehicle-nontraffic in 21% and falls in 8%. Overall, there were more unexpected survivors than patients who died. The Z score for survivors was 4.95, and the W score was 5.65. CONCLUSIONS: In the setting of a geographically isolated, medium-volume trauma centre where blunt injuries predominate, excellent trauma survival can be achieved without meeting all trauma centre guidelines for staffing and facilities. Relaxing stringent requirements for the availability of physicians may facilitate surgical recruitment and retention.

Adolescent↗

PubMed1997

Calcitonin gene-related peptide and reperfusion injury.

Calcitonin gene-related peptide is a potent intrinsic vasodilator, can induce prostacyclin release, and may inhibit membrane lipid peroxidation. This study examines the effect of calcitonin gene-related peptide on vessel diameters, capillary perfusion, and contractile function of skeletal muscle after 4 or 5 hours of ischemia and during immediate reperfusion using the rat cremaster muscle model. Forty-two male rats were used; half of these received 0.2 ml of 10(-7) M calcitonin gene-related peptide after 0, 15, and 30 minutes of reperfusion, while the other half received normal saline as a control. By means of intravital videomicroscopy, the diameters of 10 vessels per muscle were measured prior to ischemia and during reperfusion. The fluorescein filling area was determined at 15, 30, and 60 minutes of reperfusion. After 1 hour of reperfusion, muscle function was examined in vitro by quantifying the contractile response to electric field stimulation of the muscles in an organ bath system. There was a significant increase in the diameter of the arterioles, but not the small arteries, at every time point from 10 to 60 minutes of reperfusion. The fluorescein filling area was increased in treated muscles at every time point. Contractile function was not significantly preserved. In light of the ability of calcitonin gene-related peptide to relieve vasospasm and improve capillary perfusion, it may be useful in reducing reperfusion injury in the future.

Animals↗

PubMed1997

Development and implementation of an extremity free-tissue-transfer database.

Rigorous clinical outcomes research requires accurate, complete, and standardized data. No such system is currently being used by reconstructive microsurgeons to evaluate free-tissue-transfer procedures. To facilitate collection of relevant and complete data, the authors propose a standardized format for data collection regarding these procedures. Data are collected via computer entry or scannable forms. The database includes sociodemographic, clinical, health/functional status, patient satisfaction, and resource utilization variables--the necessary components of a well-constructed clinical outcome study. Such studies will give rise to meaningful treatment algorithms for managing reconstructive problems. In addition, widespread use of a standardized databse will facilitate comparisons between practices and allow for meta-analyses. Resultant practice guidelines and microsurgery care maps will ultimately improve patient care and minimize unnecessary costs.

Databases, Factual↗

PubMed1997

Techniques for reducing therapy-interfering behavior in patients with borderline personality disorder. Similarities in four diverse treatment paradigms.

Successful management of patient behaviors that interfere with the process of psychotherapy is essential to treating patients with borderline personality disorder. Provocative patient behaviors that induce a strong negative reaction from the therapist must be attenuated. Strategies for doing so used in four different treatment paradigms--Kernberg's expressive psychotherapy, Linehan's dialectical behavior therapy, Benjamin's interpersonal psychotherapy, and Allen's unified psychotherapy--are examined, and striking similarities are seen. A theoretical model is proposed to explain why the techniques may be effective.

Borderline Personality Disorder↗

PubMed1997

Orthopaedic implant infections: current management strategies.

Orthopaedic joint replacement and spinal stabilisation surgery has provided pain relief and functional improvement for millions. Postoperative infections involving the implanted hardware can have devastating functional, emotional and financial consequences. Implementation of relevant preoperative patient preparation, utilisation of appropriate prophylactic antimicrobials and intraoperative infection control measures have combined to diminish orthopaedic implant infection frequency significantly. Our adeptness at establishing the presence of an implant-related infection with certainty is not as well advanced. Similarly, treatment guidelines, while useful, remain somewhat anecdotal. The pathogenesis, risk factors, diagnosis, management and prevention of hip arthroplasty infection and spinal stabilisation with instrumentation infection are reviewed.

Antibiotic Prophylaxis↗

PubMed1996

Trends in human immunodeficiency virus seroprevalence among injection drug users entering drug treatment centers, United States, 1988-1993.

National unlinked sentinel surveillance data were used to describe trends in prevalent human immunodeficiency virus infection among injection drug users entering drug treatment programs in the United States from 1988 through 1993. During this 6-year period, unlinked testing was performed on 70,882 specimens from injection drug users at 60 sentinel sites. The annual change in seroprevalence was estimated for each site by odds ratios obtained from logistic regression models fit within site-specific age and race/ethnicity subgroups. Overall trends for age and race/ethnicity subgroups across sites were described by summary odds ratios calculated using the inverse variance method. A decrease was observed among younger (age less than 30 years) whites both in areas with high (10% or higher) and low (less than 10%) prevalence, although this decrease was significant only in high-prevalence areas (odds ratio = 0.90, 95% confidence interval 0.81-0.99). Seroprevalence also decreased among older whites in high-prevalence areas, although this decrease was not significant (odds ratio = 0.95, 95% confidence interval 0.89-1.00). Seroprevalence remained stable among all other age and race/ethnicity subgroups. Stable seroprevalence among the dynamic population of injection drug users entering treatment suggests continued transmission among these individuals in both high- and low-prevalence areas of the United States.

Adult↗

PubMed1996

Childhood fever.

Childhood fever is a common symptom, reflective of multiple causes. As the child is often unable to express himself, the physician must rely on parents' observations and the physical examination. The majority of febrile children have non-bacterial upper respiratory tract infection and indiscriminate use of antibiotics is inappropriate, ineffective and leads to drug-resistance such as the emergence of Penicillin-resistant Streptococcus pneumoniae. In this article, we attempt to identify the possible causes of fever by a simple approach using the presence or absence of associated or localising symptoms. Infants less than 3 months constitute a unique group as the fever may be related to perinatal events and as serious bacterial infections can still occur despite unremarkable physical findings. Management of fever needs to take into account the toxicity, immune status and age of the patients as well as the source of the infection. Zealous overprescription of antipyretics needs to be avoided with attention directed to the cause of the fever, the child's capacity to cope with the illness and parental education.

Analgesics, Non-Narcotic↗

PubMed1996

Bronchoscopy in immunocompromised host with pulmonary infiltrates.

Pulmonary complications related to immunosuppression may be secondary to infection, neoplasia, toxic effects of chemotherapy and radiotherapy or the primary disease itself. The diagnostic yield from bronchoscopic studies on immunocompromised hosts (ICH) with pulmonary infiltrates varies widely and the indication and timing for bronchoscopic procedures remain uncertain. We prospectively studied 60 consecutive ICH with pulmonary lesions over a 12-month period. Bronchoscopic studies were performed as soon as pulmonary lesions were detected and within 72 hours of antimicrobial treatment. The patients were divided into two groups: E (40 patients) and L (20 patients) were bronchoscoped on average 1.6 days (SD 0.8) and 16.7 days (SD 10.8) respectively after clinical detection and antimicrobial treatment. A total of 131 bronchoscopic procedures were performed. These included bronchoalveolar lavage 60, bronchoscopic lung biopsy 47, bronchial biopsy 8, brushing 8 and washing 8. Diagnostic yields for bronchoscopically obtained fluid and tissue histology were 45% and 49% respectively. Both complement each other resulting in a higher diagnostic yield of about 70% of the patients in both groups. Procedural complications were minor (13% of cases) and mortality was zero. Infections accounted for approximately two-thirds of the pulmonary lesions. Patients bronchoscoped earlier received less antimicrobial empiric therapy and had shorter hospitalisation. Despite delayed bronchoscopy in ICH in the late group, bronchoscopic results influenced in 85% of patients. However, based on earlier use of appropriate therapy, shorter hospitalisation and decreased costs, we recommend early bronchoscopy when response to empiric treatment has been unsatisfactory.

Adolescent↗

PubMed1995

Thermal control of rod outer segment length and shedding in a fish, Fundulus zebrinus.

The effects of temperature on rod outer segment (ROS) length and membrane shedding were studied in a cyprinodont fish, Fundulus zebrinus. After 30 days in 14L/10D cyclic light and 17 degrees C, ROS length averaged 41.2 microns. Fish were then exposed to 7, 17 or 27 degrees C for 10 and 25 days before being sampled 5 hr before and 1-4 hr after light onset. In 7 degrees C ROS shortened to 83.5% of initial controls within 10 days, then only 4.1% further, to 79.4% by day 25 (34.4, 32.7 microns). ROS length did not change significantly in fish remaining at 17 degrees C (39.7 and 40.7 microns at day 10 and 25) or in fish moved to 27 degrees C (41.7 and 41.6 microns). Phagosomes were most numerous in 7 degrees C and least numerous in 17 degrees C, but varied in overall size among the largest phagosomes being more common after light onset. After light onset at day 25, the estimated volume per phagosome was 1.14, 4.73 and 5.75 microns 3 in 7, 17 and 27 degrees C. Total phagosome volume per 100 microns RPE at 27 degrees C was generally double that at 17 degrees C. Apparently, in F. zebrinus, the number of disks shed from ROS is adjusted during thermal acclimation to stabilize ROS length.

Acclimatization↗

PubMed1995

Pathophysiology and related studies of the no reflow phenomenon in skeletal muscle.

Although the success rate of microvascular replantation and revascularization procedures has increased steadily since the 1960s, some replanted tissues do not reperfuse despite technically adequate arterial anastomoses. This failure of microvascular perfusion is termed no reflow. Much research has been directed toward discovering the etiology of no reflow since it was first described 25 years ago. Three pathophysiologic processes have been identified as playing a central role in the development of no reflow: intracellular calcium overload, oxygen-free radical medicated damage, and altered arachidonic acid metabolism. The first tissue believed to be injured irreversibly by these processes is the endothelium, which leads to dysfunction of the parenchymal cells. All 3 pathways are interrelated extensively, which allows for pharmacologic intervention at many different steps. Agents that have been shown to be beneficial in preventing no reflow include calcium channel blockers, prostaglandin analogs, thromboxane synthesis inhibitors, vasodilators, thrombolytics, and many antioxidants. Although they have been shown to be effective in various laboratory models, additional investigation is necessary before these treatments can be established in clinical use.

Animals↗

PubMed1994

Factitious HIV infection: the importance of documenting infection.

OBJECTIVE: To examine possible causes for factitious human immunodeficiency virus (HIV) infection among patients in an HIV clinic. DESIGN: Retrospective chart review, a case-control study, and a survey of local hospital practices for documenting HIV infection. SETTING: Clinical acquired immunodeficiency syndrome (AIDS) program at a municipal hospital. RESULTS: Seven patients with self-reported, undocumented HIV infection were identified as HIV seronegative after a mean of 9.2 months of care in our clinical AIDS program. The median CD4 count for these patients was 740 cells/mm3; 6 patients had a history of illicit narcotic use and clinical symptoms consistent with HIV disease. Compared with 70 randomly selected controls from HIV clinics, patients with factitious HIV infection had higher CD4 counts (difference, 519 cells/mm3; P < 0.001) and were more likely to have an HIV-infected sexual partner (odds ratio, 15.0; P = 0.005) and a history of a suicide attempt (odds ratio, 9.8; P = 0.02). Known cases of alleged HIV infection have occurred at 8 of the 10 other local hospitals surveyed. However, only 1 of the 10 hospitals routinely documented HIV infection in patients before initiating care. CONCLUSIONS: Limitations of the current serologic tests for HIV, the use of anonymous HIV testing, and recent reports of factitious HIV disease or immune deficiency syndromes that may mimic AIDS underscore the need for clear documentation of HIV infection before medical care is started.

Adult↗

PubMed1994

Behavioural risk factors and HIV infection of injection drug users at detoxification clinics in Puerto Rico.

BACKGROUND: The ethnic and geographical variations of AIDS prevalence among injection drug users (IDU) have highlighted the need to understand the role of the relevant risk factors in specific subpopulations of IDU. In this study we examine the factors related to seropositivity among IDU entering drug detoxification facilities in metropolitan San Juan, Puerto Rico. METHODS: From October 1990 until August 1991, 390 IDU were interviewed. Four groups of risk factors were examined: sexual practices, drug injection behaviours, risk behaviours while in US Mainland cities, and while incarcerated. A stepwise logistic regression model was used to simultaneously assess the independent effects of the behavioural risk factors on HIV seropositivity. RESULTS: Of the 342 IDU who were tested for HIV antibodies, 29.5% were seropositive. The behaviours found to be associated with seropositivity were: having sex with an IDU in the last 6 months; having injected drugs for over 5 years; and injecting with used needles while incarcerated. DISCUSSION: Public health programmes will need to establish more effective collaborative links with correctional institutions in order to reduce the spread of HIV among IDU in Puerto Rico.

Adult↗

PubMed1994

Malaria: prophylaxis and therapy.

Malaria remains a significant cause of morbidity and mortality in many regions of the world. In Singapore, an average of 200 cases of malaria have been reported annually, the majority of which are imported cases. Malaria eradication is a goal that may not be achieved. A more realistic aim is to educate and protect individual travellers. This paper attempts to summarise various therapeutic options including the use of monotherapy and combination therapy. The decision on therapy depends on several factors, such as the Plasmodium species, risk of transmission of the resistant parasite and the severity of infection. So far, none of the chemoprophylactic regimens available can provide an absolute protection from malaria transmission. Therefore, one needs to assess the risk of transmission against the potential risk of adverse drug reaction. Complications of anti-malaria drugs may range from minor cutaneous manifestations to death. General measures to prevent vector transmission of the disease should be emphasised while awaiting the development of an effective malaria vaccine.

Animals↗

PubMed1994

Advice for the international traveller.

International travel has increased in recent years. The spectrum of disease associated with travel is wide. All travellers should be encouraged to seek pre-travel medical advice which include the need for vaccination and malaria prophylaxis and advice on preventive health measures during travel. The returning traveller with an illness should be advised to seek post-travel treatment.

Antimalarials↗

PubMed1994

Randomised study comparing imipenem/cilastatin to ceftriaxone plus gentamicin in cancer chemotherapy-induced neutropenic fever.

Prompt initiation of empiric antibiotic therapy is the cornerstone in the therapy of chemotherapy-induced neutropenic sepsis in cancer patients. Ceftriaxone plus gentamicin (ceftriaxone/gentamicin) is the most widely used combination of empiric antibiotics in the Department of Medical Oncology, Singapore General Hospital. However, imipenem/cilastatin has been shown to be a practical alternative. To compare the efficacy and cost effectiveness of monotherapy with our usual combination antibiotic therapy, 50 evaluable neutropenic cancer patients admitted for fever were randomised to empiric imipenem/cilastatin or ceftriaxone/gentamicin. Ceftriaxone/gentamicin was started in 24 patients. The initial clinical response rate to ceftriaxone/gentamicin was 62.5% and 84.6% to imipenem/cilastatin (P = 0.075). The average cost of antibiotics per patient started on ceftriaxone/gentamicin including cost of change of antibiotics was S$63 per day of antibiotic use and for imipenem/cilastatin it was S$252 (P < 0.02). In conclusion, although more patients receiving imipenem/cilastatin had an initial clinical response than those receiving ceftriaxone/gentamicin, this difference was not statistically significant. It would appear that imipenem/cilastatin is equivalent to ceftriaxone/gentamicin for the treatment of neutropenic sepsis. However, ceftriaxone/gentamicin was more cost effective.

Antineoplastic Agents↗

PubMed1994

Update of systemic antimicrobials: emphasis on oral agents.

There has been a proliferation of antimicrobial agents in the market and we can expect many more new agents to be available for use in the hospital and community later. In the outpatient setting, the number of oral antimicrobial agents are varied, providing greater flexibility in managing community acquired infections. Unfortunately, the extensive use of antimicrobial agents has contributed to the development of resistance of some bacteria to multiple antimicrobials. This paper will review the basis of activity of antimicrobial agents commonly used in the outpatient clinic. The spectrum of antibacterial activity of these agents is discussed in relation to the common organisms encountered in general practice. Guidelines for the control of the development of bacterial antimicrobial resistance are also given.

Administration, Oral↗

PubMed1994

HIV infection among non-injecting drug users entering drug treatment, United States, 1989-1992. Field Services Branch.

OBJECTIVE: To describe HIV seroprevalence among non-injecting drug users (non-IDU) entering sentinel drug treatment centers in the United States. DESIGN: Anonymous, blinded (unlinked) HIV seroprevalence surveys. SETTING: Sixty-eight sentinel drug treatment centers in 37 United States metropolitan areas. PARTICIPANTS: Consecutive sample of clients admitted to sentinel drug treatment centers from January 1989 through December 1992. Of 84,617 clients, 37,633 (44.5%) had used illicit drugs but reported no injecting drug use since 1978. MAIN OUTCOME MEASURES: Center-specific, metropolitan area-specific, and national median HIV seroprevalence rates. RESULTS: National median center-specific HIV seroprevalence among non-IDU was 3.2% (range, 0-15.2%). Rates varied widely by geographic area. Median rates were highest in the northeast (5.6%; range, 0-15.2%), intermediate in the south (3.4%; range, 0.6-8.0%), and generally lower throughout the rest of the country: midwest (1.3%; range, 0-3.1%) and west (1.8%; range, 0-14.5%). When stratified by treatment center, there were few statistically significant differences in seroprevalence among African Americans, Hispanics and whites. The median rate was 3.4% among men and 2.7% among women. Rates among non-IDU were lower than among IDU attending the same drug treatment centers, but consistently higher than among heterosexual patients attending sexually transmitted disease clinics in the same metropolitan areas. CONCLUSIONS: HIV seroprevalence among non-IDU entering drug treatment is high in many metropolitan areas. HIV prevention and education efforts in drug treatment centers should target sexual as well as drug-use risk reduction for all clients.

Adolescent↗

PubMed1994

HIV infection among homeless adults and runaway youth, United States, 1989-1992. Field Services Branch.

OBJECTIVES: Homeless persons have an increased risk of HIV infection because of a high prevalence of HIV-related risk behaviors. These include drug use, sexual contact with persons at risk for HIV infection, and the exchange of sex for drugs. The objectives of this investigation were to describe HIV seroprevalence rates in homeless adults and runaway youth. METHODS: In 1989, the Centers for Disease Control and Prevention began collaboration with state and local health departments to conduct HIV seroprevalence surveys in homeless populations. Unlinked HIV seroprevalence surveys were conducted in 16 sites; 11 provided medical services primarily to homeless adults, and five to runaway youth aged < 25 years. RESULTS: From January 1989 through December 1992, annual surveys were conducted in 16 sites in 14 cities. Site-specific seroprevalence rates ranged from 0-21.1% (median, 3.3%). Among homeless adults in three sites, rates were higher among men who had sex with other men and those who injected drugs than among persons with other risk exposures (28.9 versus 5.3%). In general, rates were higher for heterosexual men than for women and higher among African Americans than whites. In sites providing services to homeless youth, HIV seroprevalence rates ranged from 0-7.3% (median, 2.3%). CONCLUSIONS: These data indicate that HIV infection among homeless adults and runaway youth is an important public health problem. HIV prevention and treatment should be integrated into comprehensive health and medical programs serving homeless populations.

Adolescent↗