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Biomedical subjects

M J Allen

Publications and source records attributed to M J Allen.

At least 109 records · Page 6Linked to original sources
PubMed1991

Deaths following trauma: an audit of performance.

The TRISS methodology was applied to identify preventable trauma deaths in a retrospective audit of 267 (M = 0.908) patients admitted to a teaching hospital through the resuscitation room of its accident and emergency department during a 1-year period. No unexpected survivors were identified; of the 44 deaths (Z = 5.35), 25 (56.8%) were judged preventable by the TRISS method. Those deaths deemed preventable were subjected to peer review by a panel of six consultants. The findings are discussed in respect of recommendations made for UK trauma centre provision by the Working Party Report of the Royal College of Surgeons of England on the management of patients with major injuries.

Adolescent↗
PubMed1990

Enumeration of total coliforms and Escherichia coli from source water by the defined substrate technology.

Many water utilities are required to monitor source water for the presence of total coliforms, fecal coliforms, or both. The Colilert system, an application of the defined substrate technology, simultaneously detects the presence of both total coliforms and Escherichia coli directly from a water sample. After incubation, the formula becomes yellow if total coliforms are present and fluorescent at 366 nm if E. coli is in the same sample. No confirmatory tests are required. The Colilert system was previously assessed with distribution water in a national evaluation in both most-probably-number and presence-absence formats and found to produce data equivalent to those obtained by using Standard Methods for the Examination of Water and Wastewater (Standard Methods). The Colilert system was now compared with Standard Methods multiple-tube fermentation (MTF) for the enumeration of total coliforms and E. coli from surface water. All MTF tubes were confirmed according to Standard Methods, and subcultures were made to identify isolates to the species level. The Colilert system was found equally sensitive to MTF testing by regression, t test, chi-square, and likelihood fraction analyses. Specificity of the Colilert system was shown by the isolation of a species of total coliform or E. coli after the appropriate color change. The Colilert test can be used for source water samples when enumeration is required, and the benefits previously described for distribution water testing--sensitivity, specificity, less labor, lower cost, faster results, no noncoliform heterotroph interference--are applicable to this type of water analysis.

Chi-Square Distribution↗
PubMed1990

Efficacy of beta-glucuronidase assay for identification of Escherichia coli by the defined-substrate technology.

In 1976, Kilian and Bulow described the association of beta-glucuronidase with the genus Escherichia (97% positive) and suggested that a beta-glucuronidase assay would be a useful identification test. Since that report, papers about the sensitivity and specificity of this enzyme for the identification of Escherichia coli from clinical sources, food, seawater, potable-water supplies, and various environmental sources have appeared. A study was undertaken to determine the efficacy and specificity of the defined-substrate technology beta-glucuronidase (Colilert) assay for the identification of this species from fecal samples. A total of 460 human, 105 cow, and 55 horse E. coli isolates were tested. Results showed 95.5% beta-glucuronidase-positive isolates in 24 h and 99.5% positive after 28 h of incubation. Only one E. coli isolate was negative. There were no significant differences in the percentage of beta-glucuronidase-positive isolates among the human or animal isolates. There were no non-E. coli isolates that were positive. All subjects carried beta-glucuronidase-positive E. coli.

Animals↗
PubMed1990

Compartment syndromes of the lower limb.

Compartment syndromes of the lower limb occur as an over-use type injury in athletes resulting in a chronic compartment syndrome. Alternatively they may occur as a result of trauma to the limb in the form of soft tissue injury or a closed fracture resulting in an acute compartment syndrome. Chronic compartment syndromes present as pain in the lower legs during exercise and are relieved after a variable period of rest. Diagnosis is aided by intracompartmental pressure monitoring during exercise and if symptoms have persisted for longer than 6 months treatment is by means of a subcutaneous fasciotomy. Acute compartment syndromes are relatively rare and often difficult to diagnose. If unrecognized they may lead to significant limb morbidity in the form of paraesthesia and muscle weakness. Diagnosis once again may be aided by intracompartmental pressure monitoring. Once the diagnosis has been made urgent surgical decompression in the form of an open fasciotomy is mandatory.

Acute Disease↗
PubMed1989

Peritoneovenous shunting as compared with medical treatment in patients with alcoholic cirrhosis and massive ascites. Veterans Administration Cooperative Study on Treatment of Alcoholic Cirrhosis with Ascites.

The optimal management of severe ascites in patients with alcoholic cirrhosis has not been defined. in a 5 1/2-year study, we randomly assigned 299 men with alcoholic cirrhosis, who had persistent or recurrent severe ascites despite a standard medical regimen, to receive either intensive medical treatment or peritoneovenous (LeVeen) shunting. We identified three risk groups: Group 1 had normal or mildly abnormal results on liver-function tests, Group 2 had more severe liver dysfunction or previous complications, and Group 3 had severe prerenal azotemia without kidney disease. For the patients who received the medical treatment and those who received the surgical treatment combined, the median survival times were 1093 days in Group 1, 222 days in Group 2, and 37 days in Group 3 (P less than or equal to 0.01) for all comparisons). For all the groups combined, the median time to the resolution of ascites was 5.4 weeks for medical patients and 3.0 weeks for surgical patients (P less than 0.01). Within each risk group, mortality during the initial hospitalization and median long-term survival were similar among patients receiving either treatment. However, the median time to the recurrence of ascites in Group 1 was 4 months in medical patients, as compared with 18 months in surgical patients (P = 0.01); in Group 2 it was 3 months in medical patients as compared with 12 months in surgical patients (P = 0.04). The median duration of hospitalization was longer in medical patients than in surgical patients (6.1 vs. 2.4 weeks in Group 1 [P less than 0.001] and 5.0 vs. 3.1 weeks in Group 2 [P less than 0.01]). Group 3 was too small to permit a meaningful comparison. During the initial hospitalization, the incidence of infections, gastrointestinal bleeding, and encephalopathy was similar among the medical and surgical patients. We conclude that peritoneovenous shunting alleviated disabling ascites more rapidly than medical management. However, survival was closely related to the severity of the illness at the time of randomization and was not altered by shunting.

Ascites↗
PubMed1989

Desmin-containing intermediate filaments: structural analysis using monoclonal antibodies.

1. Monoclonal antibodies have been raised against N- and C-terminal desmin sequence regions. 2. The antibodies decorated desmin intermediate filaments in a helical fashion with four antibody molecules per helix turn. 3. The filaments could be decorated with both types of antibody consecutively. 4. These results support a model of intermediate filament assembly in which the tetrameric protofilaments are aligned in a staggered fashion with partial overlapping of the central rod domain regions of the desmin sequence.

Animals↗
PubMed1989

The conservative management of volar avulsion fractures of the P.I.P. joint.

A retrospective study was made of 74 volar avulsion fractures of the P.I.P. joint in which there was no radiological evidence of subluxation. Overall, 96% of those reviewed achieved good results but morbidity was increased by immobilisation. Providing the joint is stable, simple neighbour strapping is recommended for these injuries.

Adolescent↗
PubMed1989

Effects of atrial natriuretic peptide on systemic haemodynamics and cardiac function in normal man.

Atrial natriuretic peptides (ANP) reduce blood pressure. Animal experiments suggest that this depressor action results from a reduction in cardiac output rather than peripheral vascular resistance but it is unresolved whether this is wholly due to their effect of reducing left ventricular filling or whether they have a negatively inotropic effect. We have therefore investigated the effects of ANP in normal man using Doppler measurements of ascending aortic blood flow. Six normal volunteers underwent infusions of placebo and incremental doses of ANP in the range 0.25 to 12 micrograms.min-1. Each infusion was given for 15 min and measurements made both in the supine and erect positions (passive tilt). In both positions ANP had dose dependent effects of increasing heart rate (HR) and maximal acceleration whilst lowering an index of systemic vascular resistance (ISVR). In the erect position ANP also lowered systolic blood pressure. In the 30 min after completion of the infusions there were significant decreases in peak velocity and cardiac output with increases in ISVR in both positions, but HR fell and diastolic pressure increased only when supine. During the course of the experiment mean haematocrit (SEM) increased from 43.9 (1.2) to 46.7 (1.0), indicating a mean reduction in plasma volume of 10.5%. This occurred despite a negative fluid balance of only 31(7) ml over the 2 h. These data suggest that ANP is not negatively inotropic and that, at pharmacological doses, it is an arteriolar dilator of rapid offset and reduces cardiac filling pressures by a mechanism of slower offset.

Adult↗
PubMed1989

A comparison of head-down tilt with low-dose infusion of atrial natriuretic peptide in man.

1. Procedures that increase atrial pressure, such as head-down tilt, result in an increase in plasma atrial natriuretic peptide (ANP) and a natriuresis, but a direct cause-and-effect relationship between these two responses has not been established. This study was undertaken to compare the effects of head-down tilt with exogenous ANP on renal function. 2. Eight normal sodium-replete volunteers underwent a 3 h placebo infusion, a 3 h ANP infusion at 1.2 pmol kg-1 min-1 and a 3 h period of head-down tilt. Each procedure was performed on a separate day, in random order. 3. ANP and head-down tilt produced similar increases in sodium excretion (65 +/- 24 and 68 +/- 16%, respectively). ANP did not increase urine flow significantly more than placebo. Head-down tilt increased urine flow significantly more than placebo and ANP. 4. Plasma ANP rose from 8.1 +/- 1.0 to 11.4 +/- 2.5 pg ml-1 during head-down tilt and from 6.5 +/- 1.4 to 32.3 +/- 10.7 pg ml-1 with ANP infusion. 5. ANP infusion had no significant effects on systemic haemodynamics whilst head-down tilt increased cardiac output and reduced heart rate and an index of systemic vascular resistance. 6. ANP infusion, whilst achieving a natriuretic response similar to that of tilt, was associated with a 3-fold higher mean plasma ANP level. Although plasma ANP rose during both ANP infusion and tilt, there was a lack of correlation between natriuretic response and plasma ANP. 7. The results are not compatible with a direct cause-and-effect relationship between plasma ANP and sodium excretion during head-down tilt.

Atrial Natriuretic Factor↗
PubMed1989

National field evaluation of a defined substrate method for the simultaneous detection of total coliforms and Escherichia coli from drinking water: comparison with presence-absence techniques.

A defined substrate method was applied to drinking water to simultaneously enumerate total coliforms and total Escherichia coli directly from samples. After incubation at 35 degrees C for 24 h, the development of yellow in an initially colorless solution was specific for total coliforms; fluorescence at 366 nm in the same tube(s) or vessel demonstrated the presence of E. coli. No confirmatory or completed steps were necessary. Known as autoanalysis colilert (AC), this method was constituted as a presence-absence test and compared with the methods described in Standard Methods (SM) in the P-A format. Seven water utilities representing a wide geological and hydrological spectrum participated in the evaluation. A total of 702 split drinking water samples were analyzed. Of these, 358 were negative in both tests (SM- and AC-); 302 were positive (SM+ and AC+); and 42 were mixed (SM+ and AC-, 20; AC+ and SM-, 22). The overall agreement rate was 94%. Comparison of the SM and AC results by nonparametric statistics demonstrated no differences. Heterotrophic plate count bacteria exerted no discernible effect on the AC test. By subculture, each time the AC test was yellow, a total coliform was present; when the test was fluorescent, E. coli was isolated.

Colony Count, Microbial↗
PubMed1989

Pulse oximetry in the accident and emergency department.

The early detection and treatment of hypoxia is important to reduce patient morbidity in the accident and emergency department. At present, the commonly used methods all have practical difficulties in the urgent situations that prevail in the department. Pulse oximetry has recently become a method of choice in many anaesthetic and intensive care units for the continuous monitoring of oxygenation and the early detection of hypoxia. As similar conditions prevail in the accident and emergency department, we have attempted to evaluate its ease of use and the quality of information obtained in our department. Patients presenting with chest pain to an accident and emergency department have their oxygen saturation measured by the pulse oximeter finger probe prior to the commencement of oxygen therapy. After 5 min of oxygen therapy, the measurement was repeated. Our result showed that although no patients could be judged as hypoxic on clinical grounds the pulse oximeter showed, within 30 s of admission, that a number had an abnormal oxygen saturation. Continuous monitoring with the probe after the application of low flow oxygen therapy also aided in monitoring their treatment and this improvement was again easily and quickly recorded. Our experience shows that the pulse oximeter may be a useful tool for evaluating hypoxia and oxygen therapy in the accident and emergency department and we feel that we should be one of the groups who should reply in the positive to Zorab's question, 'Who needs pulse oximetry?' (Zorab, 1988).

Accidents↗
PubMed1989

University students' support for heterosexual women with AIDS.

Support for a woman heterosexual AIDS victim was examined among 237 university students, 54% female and 54% upper division, with a mean age of 23.7 yr. A questionnaire containing one of four scenarios (AIDS resulting from unsafe sex, unsafe drug use, sex with an unfaithful husband, or a blood transfusion) measured support by people's willingness to sign or circulate a petition supporting the victim's right to attend college classes. A five-way mixed-design analysis of variance showed that victims who took risks received less support, that respondents were more willing to sign than to circulate a petition, and, while men did not discriminate among the four scenarios, women were most likely to offer support to "innocent" victims who contracted AIDS without sexual behavior. In addition, respondents who knew someone with AIDS were more likely to sign the petition. AIDS, particularly when contracted through risky behavior, is a disease with social ramifications beyond its threat to public health.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The effect of local angiotensin converting enzyme inhibition on the action of atrial natriuretic peptide in the human forearm.

It has been suggested that angiotensin converting enzyme (ACE) may play a role in the metabolism of atrial natriuretic peptide (ANP), and that ANP may interfere with angiotensin-induced vasoconstriction. This has been investigated within the forearm vascular bed during local ANP infusion and ACE inhibition. Six normotensive volunteers were studied, each on two occasions. On both occasions, after saline infusion, volunteers were given initially a 20 min infusion of ANP at 0.1 microgram/min via the brachial artery. This was followed, after 20 min, by a second infusion of ANP at the same dose, co-infused with enalaprilat (5 micrograms/min) on one occasion, and placebo (saline) on the other (in random order). Forearm blood flow was measured using venous occlusion plethysmography with mercury-in-silastic strain gauges. Blood flow in the cannulated arm increased significantly during the first ANP infusion; by 52 +/- 15% before placebo (P less than 0.05), and by 41 +/- 8% before enalaprilat (P less than 0.005). This increase was similar with the second ANP infusion during co-infusion of either placebo (40 +/- 10%) or enalaprilat (45 +/- 11%). Enalaprilat did not affect the half-life of vasodilatation produced by ANP (t1/2 = 5 min). These studies in healthy subjects demonstrate no effect of local ACE inhibition on resting blood flow, or on the vasodilatation produced by ANP in the human forearm, and provide no evidence of a role of ACE in the metabolism of ANP in this vascular bed.

Adult↗