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Biomedical subjects

P Davidson

Publications and source records attributed to P Davidson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Pneumothorax as a complication of laparoscopic inguinal hernia repair.

Pneumothorax was identified as a complication of endoscopic hernia repair in two patients with insufflation pressures of 15 mmHg and operating times exceeding 2 h. These patients also showed intraoperative perturbations in both oxygen saturation and end-tidal CO2 production. A prospective study was undertaken to determine whether similar complications would arise if preperitoneal insufflation pressures were limited to 10 mmHg. Postoperative chest x-rays were obtained on all patients to check for pneumothoraces, even clinically occult ones. Fifty patients were studied, with average operating times of 67 min. No patient demonstrated any hemodynamic or ventilatory changes, and none had any evidence of pneumothorax on x-ray. We conclude that these complications were not present when insufflation pressure was maintained at 10 mmHg and that routine x-ray is not warranted. Larger randomized trials of insufflation pressures are needed.

Adult↗
PubMed1997

Risk of concurrent prostate cancer in cystoprostatectomy specimens is related to volume of high-grade prostatic intraepithelial neoplasia.

OBJECTIVES: To assess the relationship of prostatic intraepithelial neoplasia (PIN) with both incidental and clinical carcinoma of the prostate. METHODS: We retrospectively reviewed prostate histology in 48 men (group 1) who underwent surgical removal of the prostate for diagnoses other than prostate cancer, as well as in 64 men (group 2) who underwent radical prostatectomies. Both groups were assessed for the presence and extent of high-grade (HG-) PIN and compared with respect to patient age, Gleason score, and volume of prostate cancer. RESULTS: HG-PIN was present in 40 of 48 (83%) group 1 cases. Forty-six percent of these cases (22 of 48) had incidental prostate cancer. Twenty-nine of 48 (60%) group 1 patients with HG-PIN had multifocal or extensive disease. Twenty of 22 (91%) incidental prostate cancers were present in 29 prostates with multifocal or extensive HG-PIN. In contrast, only 2 of 19 (11%) cases with absent to focal HG-PIN had prostate cancer. The association of multifocal or extensive HG-PIN with incidental prostate cancer was significant (P = 0.001); the relationships of extent of HG-PIN and cancer volume (P = 0.06) or high Gleason score (P = 0.017) were not significant. HG-PIN was present in 61 of 64 (95%) group 2 cases. The associations of extent of HG-PIN and cancer volume (P = 0.169) or high Gleason score (P = 0.156) were not significant. CONCLUSIONS: Both the low rate of incidental prostate cancer in specimens with absent to focal HG-PIN and the high rate of cancer in specimens with multifocal or extensive HG-PIN suggest that HG-PIN is a marker for concurrent prostate cancer and that the risk of concurrent prostate cancer is related to the volume of HG-PIN in the prostate gland.

Aged↗
PubMed1997

Intoxicated ED patients: a 5-year follow-up of morbidity and mortality.

STUDY OBJECTIVES: To determine the rates of alcohol-related morbidity and mortality in a cohort of intoxicated ED patients 5 years after presentation and to compare them with those of non-intoxicated ED patients. METHODS: The study group comprised 150 consecutive ED patients who presented with intoxication (blood alcohol level higher than 100 mg/dL) in June 1986 and 50 control patients matched for age, sex, ED arrival time, and date. The setting was an urban university hospital ED. Morbidity and mortality over a 5-year follow-up period were measured using hospital ED and admission records from all state Level I trauma centers and computerized statewide databases. RESULTS: The 5-year mortality rate among alcohol-intoxicated patients was 2.4 times that of the comparison group (95% confidence interval, .3 to 18.9). The 5-year death rate among intoxicated patients aged 40 to 69 years was especially high (19%). Thirty-seven percent of the intoxicated patients made at least one alcohol-related ED revisit during the follow-up period, compared with 6% of the comparison group (P < .001). Intoxicated patients were more likely to revisit EDs because of suicidal behavior or domestic violence (P = .001). Admission to an alcohol detoxification unit during the follow-up period occurred in 24% of the intoxicated patients, compared with 10% of the sober controls (P = .03). At least one arrest for drunk driving occurred in 47% of the intoxicated group; the rate was lower, but still substantial, in the comparison group (20%, P < .001). CONCLUSION: A single alcohol-related ED visit is an important predictor of continued problem drinking, alcohol-impaired driving and, possibly, premature death.

Adolescent↗
PubMed1997

Voices from practice: mental health nurses identify research priorities.

Through a collaborative research project, nurse clinicians and nurse academics identified and prioritized the most important research questions arising from the current and future practice of mental health nurses in an eastern Canadian region. Study methods included the Delphi technique and a nominal group survey approach. Nine categories of research questions emerged. The top four categories are discussed under the headings: Preparation of Helpers, the Service System, Caregiver Needs, and Clients With Major Behavior Problems. This timely study offers explicit direction for psychiatric and mental health nursing practice and research, and for the development of social policy.

Attitude of Health Personnel↗
PubMed1997

A biopsychosocial understanding of the irritable bowel syndrome: a review.

OBJECTIVES: To review and examine the clinical and research literature on irritable bowel syndrome (IBS) with a view to establishing the role that psychiatric factors play in the pathogenesis and treatment of this syndrome. RESULTS: Comorbid psychiatric illness is common with IBS, yet only a small proportion of these patients seek medical attention. Many patients are either satisfied by reassurance or experience symptom relief from medical treatment directed at target symptoms. A small group of patients do not experience much relief, and it is largely this group who come to the psychiatrist's attention. Psychotropic medication is helpful when clinically indicated, and tricyclic antidepressants in small doses (for example, 50 mg) may be helpful for those patients with a pain-predominant pattern of IBS. Psychotherapy (including cognitive, behavioural, relaxation, thermal-biofeedback, insight-oriented therapy, and hypnosis) has been shown to provide relief, although it has often been difficult to differentiate this improvement from a placebo response. CONCLUSIONS: The group of patients with "refractory IBS" used a large amount of health care resources in an attempt to find relief to their distress. Further study is needed to gain a better understanding of which component of psychotherapy is most cost-effective and which patients are most likely to benefit. The large group of those who admit to symptoms compatible with IBS but who do not seek medical attention has to a large extent been excluded from most studies. Exploring this group may provide further insight into this perplexing syndrome.

Antidepressive Agents, Tricyclic↗
PubMed1996

Lamellar biogels: fluid-membrane-based hydrogels containing polymer lipids.

A class of lamellar biological hydrogels comprised of fluid membranes of lipids and surfactants with small amounts of low molecular weight poly(ethylene glycol)-derived polymer lipids (PEG-lipids) were studied by x-ray diffraction, polarized light microscopy, and rheometry. In contrast to isotropic hydrogels of polymer networks, these membrane-based birefringent liquid crystalline biogels, labeled L-alpha,g, form the gel phase when water is added to the liquid-like lamellar L-alpha phase, which reenters a liquid-like mixed phase upon further dilution. Furthermore, gels with larger water content require less PEG-lipid to remain stable. Although concentrated (approximately 50 weight percent) mixtures of free PEG (molecular weight, 5000) and water do not gel, gelation does occur in mixtures containing as little as 0.5 weight percent PEG-lipid. A defining signature of the L-alpha,g regime as it sets in from the fluid lamellar L-alpha phase is the proliferation of layer-dislocation-type defects, which are stabilized by the segregation of PEG-lipids to the defect regions of high membrane curvature that connect the membranes.

Chemical Phenomena↗
PubMed1996

Identification of the motor vehicle accident victim who abuses alcohol: an opportunity to reduce trauma.

OBJECTIVE: We hypothesized that a poor driving history and alcohol abuse, evident in a large number of people injured in automobile accidents, contribute to repeated injury, and that treatment for alcohol abuse may reduce vehicular trauma. METHOD: Patients (N = 150) admitted to the emergency surgical service because of injury sustained in a motor vehicle accident (MVA) were tested for their blood alcohol concentrations, and they responded to a questionnaire concerning their prior driving and medical histories. RESULTS: Contrary to the assumption that motor vehicle injuries are isolated episodes, 68% of MVA patients had experienced a prior accident, and 43% had been injured in an MVA before the present event. Prior MVAs were associated with having been previously arrested for driving while intoxicated (DWI), with illegal drug use and with prior hospitalization. Of the MVA patients, 37% were intoxicated (blood alcohol concentration [BAC] > or = 100 mg/dl). Elevated BAC was associated with having been stopped for drinking, having a restricted license, having a DWI arrest, using illegal drugs and having a previous admission to a hospital. Prior MVAs, prior DWIs, elevated BAC and male gender formed the Louisville Alcohol Abuse Predictor Checklist and were independent predictors of alcohol abuse diagnosis, based on the patient's self-report of problems with alcohol. Forty-two percent of MVA patients were diagnosed as alcohol abusers. The alcohol abuser had a significantly higher rate of recurrent MVAs, DWIs and injuries than did nonabusers. CONCLUSIONS: Surgical service may present an opportunity for assessment of alcohol abuse among MVA victims, and treatment for alcoholism might reduce vehicular trauma.

Accidents, Traffic↗
PubMed1995

Effect of ranitidine on intragastric pH and stress-related upper gastrointestinal bleeding in patients with severe head injury.

We conducted a double-blind, placebo-controlled study to evaluate the effects of ranitidine on intragastric pH and upper gastrointestinal tract bleeding in severe head injury patients. Within 24 hr of the precipitating trauma, 34 adults with Glasgow coma scale scores < or = 10 were randomized to a 6.25 mg/hr ranitidine continuous infusion or placebo for a maximum of 72 hr. Intragastric pH was recorded via an intragastric pH electrode. Patients with hematemesis, hematochezia, bright red blood, or "coffee ground" nasogastric tube aspirates plus a 5% decrease from baseline in hematocrit were considered to have gastrointestinal bleeding. Ranitidine patients maintained a significantly greater mean pH than placebo patients (placebo 2.2, ranitidine 4.1; P < 0.01). All patients had at least two bleeding risk factors at study entry. No ranitidine patients (0/16) developed bleeding compared with five (5/18) placebo patients (P < 0.05). Ranitidine continuous infusion provided consistent intragastric pH control and significant protection from stress-related upper gastrointestinal tract bleeding in a high-risk patient population.

Adult↗
PubMed1995

The biological monitoring of mercury in the Seychelles study.

The concentration of total mercury in maternal hair during pregnancy was used as a measure of fetal exposure to methylmercury in a study of a fish-eating population in the Seychelles islands. A segment of scalp hair approximately 10 centimeters in length, that grew during pregnancy, was selected for measurement. Total and inorganic mercury were measured by cold vapor atomic absorption (CVAA) using the Magos reagents (Magos, 1971). For comparative purposes, total mercury was measured by X-ray Fluorescent Spectrometry (XRF) and methylmercury by gas chromatography/atomic fluorescence detection (GC/AFD) in a subset of hair samples. A limited number of fish samples were also analyzed. Extensive interlaboratory testing was conducted to ensure accuracy of the mercury measurements. Concentrations of organic mercury calculated as the difference between total and inorganic mercury as measured by CVAA agreed with those of methylmercury measured on the same samples of hair by GC/AFD. Methylmercury measured by GC/AFD and organic mercury measured by CVAA accounted for over 80% of the total mercury in hair and over 90% of the total mercury in fish muscle. To test the accuracy of recapitulation by hair sampling, hair samples were collected from mothers at the time of delivery and 6 months later. The segment corresponding to the pregnancy term was selected for measurement assuming a hair growth rate of 1.1 cm/month. Results from both samples were in close agreement. As part of both a pilot investigation followed by the main study, maternal hair samples were collected each year from 1986 to 1989 for a total of 1604 samples. The median and mean values for each year's collection fell in the range of 5.9 to 8.2 ppm and exhibited no statistically significant trend with time. The highest recorded concentration was 36 ppm. In hair samples from 654 mothers, the mean concentration of total mercury was compared with the mean concentrations in segments corresponding to each trimester, approximately 3.3 centimeters in length. A high degree of correlation was found between mean levels in each trimester versus the entire pregnancy segment.

Child Development↗
PubMed1992

Dropout and relapse during diabetes care.

OBJECTIVE: To determine factors associated with dropout and relapse during chronic diabetes care. RESEARCH DESIGN AND METHODS: Private practice outpatient treatment-education program for adult diabetes was surveyed. Retrospective analysis was done, involving 422 patients for up to 3 yr. RESULTS: Of the patients in the study, 12% dropped out after the initial visit, and 33% of the residual cohort dropped out during each subsequent 6-mo period. Factors associated with dropout included distance from home to clinic > 100 miles, lack of insulin treatment, and cigarette smoking. In patients who remained in follow-up, a significant decrease in HbA1C occurred during the first 6 mo, but 40% of the patients relapsed between 6 and 12 mo. Frequency of relapse declined as time passed. Relapse was more frequent in women. CONCLUSIONS: Dropout from treatment and relapse after temporary improvement account for a substantial amount of uncontrolled diabetes, and overcoming the obstacles of dropout and relapse has potential for significant improvement in diabetes care.

Adolescent↗
PubMed1991

Thick malignant melanomas (greater than 3 mm Breslow) with good clinical outcome: a histological study and survival analysis.

Thick malignant melanomas in general tend to have a poor prognosis, but exceptions occur where there may be no further recurrence. The reasons for this difference in clinical behaviour are not fully understood. We have looked at thick malignant melanomas (greater than 3.0 mm) in the East of Scotland that have no evidence of metastasis after a minimum of 6 years follow-up and compared the clinical and histological features with a similar group, associated with histological evidence of metastasis and/or death. Both groups received similar treatment regimes. We have identified 41 patients with thick melanomas in the former group. When compared with the control group, factors found to be significantly different between the two groups were: the nature of the lower margin of the tumour; vascular invasion; and anatomical location.

Adolescent↗
PubMed1990

Thin malignant melanomas (less than 1.5 mm) with metastasis: a histological study and survival analysis.

It is known that not all thin malignant melanomas have an excellent prognosis and that the specific features identifying the patients at risk of metastasis have not been fully elucidated. We have looked at thin malignant melanomas (less than 1.5 mm) in the East of Scotland that had proven metastasis and death, and compared the clinical and histological features with a similar group (less than 1.5 mm) that have had no further recurrence after a minimum of 6-year follow-up. We identified 26 patients with thin melanomas who had developed histologically proven metastasis and/or died following adequate surgical treatment of their primary lesion. When compared with the control group, factors found to be significantly different between the two groups and present in the group that did badly were (a) histological regression, (b) lesion size, (c) Clark level IV and (d) depth of the uninvolved dermis.

Adult↗