PubMed Health⌕ Search

Biomedical subjects

J A Morris

Publications and source records attributed to J A Morris.

At least 19 recordsLinked to original sources
PubMed1992

X-ray microanalysis of bulk hydrated specimens of neoplastic and non-neoplastic human urothelium.

Specimens of neoplastic and non-neoplastic human urothelium were rapidly frozen against a copper block immersed in liquid nitrogen, planed in a cryoultramicrotome and then examined by low-temperature scanning electron microscopy (LTSEM) following coating by aluminium. Energy dispersive X-ray microanalysis (XRMA) was performed on the superficial urothelial cells and on gelatin blocks mounted in parallel which had known concentrations of sodium, potassium, chloride, and phosphorus. The neoplastic urothelial cells had significantly less phosphorus (P less than 0.05) than non-neoplastic cells and the ratios K+/P,K+/Na+, and K+/Cl- were significantly higher in neoplastic cells than in non-neoplastic cells (P less than 0.00001). These results are consistent with those expected in cells with a sustained increase in intracellular pH caused by stimulation of Na+/H+ ion membrane exchange.

Electrolytes↗
PubMed1992

Ageing, information and the magical number seven.

Concepts from information theory are applied to human ageing. An equation is derived, based on the general properties of information systems, which closely predicts the mortality rate in old age. The same equation predicts that infection will be increasingly severe when first exposure to micro-organisms is delayed leading to diseases which peak in early and middle age. A parameter of the equation is the level of redundancy in human information processing. Observed mortality rates show that this is sevenfold and it is suggested that seven is a fundamental dimensionless biological constant.

Adult↗
PubMed1992

Wilderness injuries and illnesses.

STUDY OBJECTIVE: To determine injury and illness patterns and occurrence rates during wilderness recreation. DESIGN: Prospective injury and illness surveillance study. SETTING: Wilderness areas throughout the Western hemisphere. TYPE OF PARTICIPANTS: All students and instructors on National Outdoor Leadership School courses over a five-year period. MAIN RESULTS: A single fatality occurred, resulting in a death rate of 0.28 per 100,000 person-days of exposure. Injuries occurred at a rate of 2.3 per 1,000 person-days of exposure. Sprains and strains and soft tissue injuries accounted for 80% of the injuries. The illness rate was 1.5 per 1,000 person-days of exposure. Sixty percent of illnesses were due to nonspecific viral illnesses or diarrhea; hygiene appeared to have a significant impact on the incidence of these illnesses. Thirty-nine percent of the injuries and illnesses required evacuation (1.5 per 1,000 person-days of exposure). CONCLUSION: The injury and illness patterns indicate that wilderness medical efforts should concentrate on wilderness hygiene and management of musculoskeletal injuries and soft tissue wounds. The data also indicate that wilderness activities can be conducted relatively safely, but the decision to participate should be individualized, with an understanding of risks versus benefits.

Adolescent↗
PubMed1992

The clinical utility of computed tomographic scanning and neurologic examination in the management of patients with minor head injuries.

The evaluation and management of patients with minor head injury (MHI: history of loss of consciousness or posttraumatic amnesia and a GCS score greater than 12) remain controversial. Recommendations vary from routine admission without computed tomographic (CT) scanning to mandatory CT scanning and admission to CT scanning without admission for selected patients. Previous reports examining this issue have included patients with associated non-CNS injuries who confound the interpretation of the data and affect outcome. We hypothesized that patients with MHI and no other reason for admission with normal neurologic examinations and normal CT scans would have a negligible risk of neurologic deterioration requiring surgical intervention. To validate this hypothesis we studied 2766 patients with an isolated MHI admitted to seven trauma centers between January 1, 1988, and December 31, 1991. There were 1898 male patients and 868 female patients; injury was blunt in 99%. A neurologic examination and a CT scan were performed on 2166 patients; 933 patients had normal neurologic examinations and normal CT scans and none required craniotomy; 1170 patients had normal CT scans and none required craniotomy; 2112 patients had normal neurologic examinations and 59 required craniotomy. The sensitivity of the CT scan was 100%, with positive predictive value of 10%, negative predictive value of 100%, and specificity of 51%. The use of CT alone as a diagnostic modality would have saved 3924 hospital days, including 814 ICU days, and $1,509,012 in hospital charges. Based on these data, we believe that CT scanning is essential in the management of patients with MHI and that if the neurologic examination is normal and the scan is negative patients can be safely discharged from the emergency room.

Adolescent↗
PubMed1992

Base deficit stratifies mortality and determines therapy.

OBJECTIVE: To determine the association of base deficit with mortality and other factors affecting mortality. DESIGN: Retrospective review. SETTING: Tertiary care center. PARTICIPANTS: Consecutive samples of 3791 trauma patients admitted with an arterial blood gas sample taken in the first 24 hours. MAIN OUTCOME MEASURES: Age, injury mechanism, head injury, shock (systolic blood pressure less than 90 mm Hg), Revised Trauma Score, TRISS probability of survival Ps, and mortality. RESULTS: Most (3038) patients (80.1%) exhibited a base deficit. Base deficit, age, injury mechanism, and head injury were associated with mortality using logistic regression. Age less than 55 years, no head injury, and a base deficit of -15 mmol/L were associated with 25% mortality. Age greater than or equal to 55 years with no head injury or age less than 55 years with a head injury and a base deficit of -8 mmol/L were associated with a 25% mortality. When shock was added to the model, all factors remained significant, and base deficit was supplemental to blood pressure. Base deficit also added significantly to the Revised Trauma Score and TRISS measurements. CONCLUSIONS: The base deficit is an expedient and sensitive measure of both the degree and the duration of inadequate perfusion. It is useful as a clinical tool and enhances the predictive ability of both the Revised Trauma Score and TRISS.

Academic Medical Centers↗
PubMed1992

Bacterial toxins: a possible cause of cot death.

AIM: To test the hypothesis that sudden infant death syndrome (SIDS) may be caused by toxins of commonly occurring bacteria in infants lacking developed immunity. METHODS: Nasopharyngeal microbial isolates from 22 pairs of SIDS cases and healthy infants matched for age (by month), sex, and sampling time (by month) were compared for lethal toxigenicity. Crude toxin preparations were made from isolates cultured on dialysis membrane overlaid on agar, and these preparations were then tested for lethality by intravenous injection into 11 day old chick embryos. RESULTS: Fifteen (68%) of the SIDS cases were each found to have at least one lethally toxigenic organism in their nasopharyngeal flora; only eight (36%) of the flora of normal infants included a lethally toxigenic species. CONCLUSION: Infants who have died of SIDS have a significantly higher (p less than 0.05) probability than matched healthy infants of having a lethally toxigenic bacterial species in their nasopharyngeal flora.

Bacteria↗
PubMed1992

Assessment of value of calibrated lyophilised plasmas to determine International Sensitivity Index for coagulometers.

An attempt was made to correct for the effects of coagulometers on the International Sensitivity Index (ISI) in a series of collaborative studies. Modified ISI were derived from the prothrombin time results with coagulometer systems using a range of calibrated plasmas. Two alternative approaches to correction of the ISI were evaluated. The first relied on the consensus orthogonal regression slopes of the prothrombin times for each coagulometer system plotted against the consensus manual results; the second depended on the local individual slope of the prothrombin times for each instrument. The two procedures were compared with the currently recommended method where International Normalised Ratios (INR) are derived from the manual ISI of the thromboplastin. The recommended method gave a significant bias from the manual results with most coagulometers. In contrast, the local correction procedure gave no significant biases, whereas the consensus method did so in a few instances. Both these correction procedures seem more reliable than the recommended method of INR derivation, but the local correction is more accurate and offers a more practical solution by allowing laboratories to determine their own corrected ISI on a range of calibrated plasmas.

Calibration↗
PubMed1992

Staphylococcal toxins and sudden infant death syndrome.

AIMS: To investigate the hypothesis that commonly occurring bacterial toxins cause sudden infant death syndrome (SIDS) by (1), determining in which tissues bacterial toxins are concentrated after intravenous injection in rats; and (2), seeing if the same tissues contain detectable toxins in cases of SIDS. METHODS: The tissue distribution of intravenously injected staphylococcal enterotoxin A (SEA), enterotoxin B (SEB), enterotoxin C (SEC), enterotoxin D (SED), toxic shock syndrome toxin (TSST-1), and alpha-haemolysin was studied in rats using immunohistology and polyacrylamide gel electrophoresis with immunoblotting. Immunostaining was also carried out on formalin fixed kidneys from cases of SIDS and a comparison series of necropsy cases using anti-SEA, anti-SEB, anti-SEC2 and anti-SED. RESULTS: Immunohistology showed that SEB, SEC, SED and TSST-1 were all concentrated in the proximal convoluted tubular cells of the kidney. The presence of these toxins was confirmed in kidney homogenates using electrophoresis and immunoblotting. There was positive granular staining in the proximal convoluted tubular cells of the kidney in 36% of SIDS cases and 12% of the comparison series with anti SEC2 (chi 2 = 6; p < 0.025). CONCLUSION: SEC, or a bacterial toxin with epitopes in common, could have a pathogenic role in SIDS.

Animals↗
PubMed1992

Lethal synergistic action of toxins of bacteria isolated from sudden infant death syndrome.

AIM: To test the hypothesis that lethal toxins of bacteria associated with sudden infant death syndrome (SIDS) can act synergistically. METHODS: Bacteria occurring together in the nasopharynx of cases of cot death were studied. The lethal toxicity of crude toxin preparations was determined over a range of dilutions by injections into the chorioallantoic vein of the chick embryo. Toxin preparations of low lethality for the chick embryo SIDS model were then tested in combination. RESULTS: Staphylococcus aureus toxin preparations showed low lethality when tested alone, even at low dilution. At 1 in 100 dilution S aureus toxin was lethal to one out of 15 chick embryos. Escherichia coli toxin preparations showed high lethality except on high dilution (1 in 80) when lethality fell to two out of 15 of chick embryos. When the same toxin preparations were tested simultaneously in combination, lethality rose to 14 out of 15. Similar findings were observed over a range of toxin dilutions. This finding was highly significant (p = 0.0012). CONCLUSIONS: That synergy between toxins can enhance the lethality of toxins elaborated by bacteria associated with SIDS.

Animals↗
PubMed1992

Possibility of separating toxins from bacteria associated with sudden infant death syndrome using anion exchange chromatography.

AIMS: To develop techniques for the characterisation of toxins elaborated by a strain of Escherichia coli associated with sudden infant death syndrome (SIDS). METHODS: E coli SIDS 04, isolated from the nasopharynx of a case of SIDS, was studied. Cell-free toxin preparations were standardised, their protein measured, and analytical separation of proteins achieved using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Acetone precipitation of proteins was required prior to Coomassie blue staining of bands. Preparative separation was achieved on an anion exchange column using a programmed concentration gradient of NaCl in TRIS buffer. Fractions were tested individually or pooled for presence of lethal toxin including endotoxin. Lethal toxin was detected with the chick embryo test system. Endotoxin was measured using a chromogenic modification of the Limulus amoebocyte assay. RESULTS: Twenty one peaks were detected by chromatography. Ten individual, or pooled, fractions were assayed for endotoxin which ranged from 27-33 pg/ml. Much greater variation was found when the same fractions were assayed in chick embryos. E coli fractions varied considerably in lethal toxicity, from 0/10 to 10/10 chick embryos killed/tested. Certain E coli fractions tested individually (lethality four out of 10 to eight out of 10) proved more lethal (10 out of 10) if pooled prior to testing. CONCLUSIONS: In E coli infection associated with SIDS relatively low concentrations of extracellular protein are lethally toxigenic for the chick embryo model of SIDS. These proteins can be separated analytically by SDS-PAGE and preparatively by anion exchange chromatography. Toxicity of individual fractions is not correlated with endotoxin concentrations in samples tested.

Animals↗
PubMed1992

Long-term follow-up of unsuccessful violent suicide attempts: risk factors for subsequent attempts.

STUDY POPULATION: Of 9046 consecutive trauma admissions, all suicide attempts (n = 156) were identified: 38 patients (24%) died in hospital; 118 (76%) were discharged and received long-term follow-up (mean = 2.8 years). Factors assessed included suicidal ideation and planning, reason for attempt; number of attempts, methods, dates of prior and subsequent attempts; psychiatric diagnoses, substance abuse history, treatment and medication compliance, hospitalizations, incidence of family depression and suicide; education level, job history, and living conditions. RESULTS: 104 (88%) patients were interviewed and 14 (12%) were lost to follow-up. Seventy-seven of the patients (74%) used guns in their attempt; their mean ISS was 14.2. Seven (6.7%) made repeat suicide attempts (all unsuccessful). Late mortality was 7% (one related to index suicide, five to chronic illness, one to motor vehicle crash). Most patients (96%) had psychiatric diagnoses at discharge, 77 of 93 (83%) had diagnosed depression. Sixty-six percent (69 of 104) had histories of alcohol abuse, 42% (42 of 101) histories of drug abuse. Thirty-five percent (34 of 96) were noncompliant with psychiatric follow-up and 70% (16 of 23) were noncompliant with alcohol abuse treatment. CONCLUSIONS: (1) Repeat attempts were rare (7%) after failed suicide attempts. (2) No late deaths resulted from repeat suicide attempts. (3) Risk factors associated with repeat attempts were younger age (p = 0.002), prior attempts (p = 0.02), family history of suicide (p = 0.03), schizophrenia (p = 0.005), and not living at home (p = 0.04). (4) Identifying patients with these risk factors, ensuring that they receive inpatient alcohol abuse treatment, along with sustained psychiatric treatment and help in maintaining home environments, may prevent repeat suicide attempts.

Adolescent↗
PubMed1992

High-level positive end-expiratory pressure management in trauma-associated adult respiratory distress syndrome.

This study evaluated the effect of high-level positive end-expiratory pressure (PEEP) on mortality, barotrauma, intrapulmonary shunt (Qsp/Qt), and oxygen delivery (DO2) in posttraumatic adult respiratory distress syndrome (ARDS). All hypoxemic trauma patients admitted to the surgical intensive care unit (SICU) in 1989-1990 who received PEEP greater than 15 cm H2O were included. The PEEP was titrated to achieve an intrapulmonary shunt (Qsp/Qt) of approximately 0.20, and FIO2 was weaned to less than 0.50. Hemodynamic and pulmonary variables at four distinct intervals were recorded. Fifty-nine patients received PEEP greater than 15 cm H2O. Of these, 19 patients died of severe head injury or uncontrollable hemorrhage (16 within 48 hours). Forty (29 male, 11 female) were evaluated in detail. The PEEP levels ranged from 18-50 cm H2O with a mean of 27. PaO2/FIO2 ratios and Qsp/Qt improved as PEEP therapy was titrated. Cardiac index and oxygen delivery were maintained or improved throughout PEEP therapy by transfusion and fluid resuscitation, with a mean maximum positive fluid balance of 21.1 L and an average of 51 units of blood and blood products transfused per patients during their SICU stay. Twenty-nine (73%) had evidence of barotrauma, the majority being pneumothoraces clearly related to the initial trauma. Only three (7.5%) had evidence of barotrauma not related to trauma or line insertion. Eight of 40 patients (20%) died. Mean ISS and RTS for the entire group were 32 and 5.88, respectively. We conclude that titration of PEEP to achieve a Qsp/Qt of approximately 0.20 is an attainable goal. This was accomplished with minimal hemodynamic effects or barotrauma and a low mortality rate.

Adolescent↗
PubMed1992

Hepatic enzyme response and hyperpyrexia after severe liver injury.

A multi-center experience with 210 severe liver injuries was reviewed to define postoperative changes in hepatic enzyme levels and body temperature profile. The 129 patients who survived initial operation comprised the data base. Serum glutamic oxaloacetic transaminase (SGOT) and lactate dehydrogenase (LDH) peaked within 24 hours (750 +/- 92 IU/L, 870 +/- 120 IU/L) and decreased rapidly during the first 4 days. Serum bilirubin was maximal at 7 days, while alkaline phosphatase rose slowly throughout 14 days. Hepatic enzyme elevations were more dramatic after blunt trauma, reflecting greater hepatocellular disruption. Maximum daily temperatures exceeding 38.0 degrees C and 39.0 degrees C were recorded for the first 3 postoperative days in 82 (64%) patients and 14 (11%) patients, respectively. No infectious source was evident in 13 (93%) of 14 patients with severe hyperpyrexia, implicating release of inflammatory mediators associated with major hepatic trauma. Convalescence from severe hepatic injury is marked by release of SGOT and LDH, as well as fever, which may be anticipated during the first 4 days postinjury.

Adult↗
PubMed1992

Pediatric organ donation: the paradox of organ shortage despite the remarkable willingness of families to donate.

The 105 pediatric deaths (ages 1 to 16 years) that occurred at Vanderbilt University Medical Center during a 31-month period were reviewed to define the size of the donor pool in the pediatric population and to assess the role of physicians in the procurement of these much-needed organs. Computerized discharge abstracts showed that 57 pediatric patients died without contraindications to organ donation. Manual review of these 57 medical records yielded 46 records suitable for review by Tennessee Donor Services. From this group, 19 eligible donors were identified. All eligible donors died from trauma, intracerebral hemorrhage, anoxic events, or hydrocephalus. Physicians failed to ask one family for permission to donate. All 18 of the families who were asked agreed to donate and organs were successfully procured from all 18 patients. These data suggest that families of pediatric patients are much more willing to agree to donation than the families of adult patients. As a result of this study, a simplified audit process has been developed for hospitals to use in evaluating compliance with required-request legislation.

Adolescent↗
PubMed1991

Trauma in pregnancy. Predicting pregnancy outcome.

A multicenter study involving three American College of Surgeons Level 1 trauma centers was undertaken to assess parameters that may predict fetal outcome. The records of 93 injured pregnant patients admitted from April 1, 1985, to March 31, 1990, were reviewed. There were three maternal deaths (3%) (mean Injury Severity Score, 43). Fourteen fetal/neonatal deaths (15%) occurred during the acute care admission period. Of these, eight were fetal deaths (two associated with maternal death), four were cases of elective abortions, and two were neonatal deaths. In general, the maternal physiologic and laboratory parameters assessed failed to accurately predict pregnancy outcome, while Injury Severity Score did differ significantly between patients whose pregnancies were viable (Injury Severity Score = 6.2) and those whose pregnancies were nonviable (Injury Severity Score = 21.6). Unique to this study were the findings that the Glasgow Coma Score also differed significantly in patients with viable (Glasgow Coma Score, 14.5) and nonviable (Glasgow Coma Score, 12.0) pregnancies, while fetal heart rate at admission to the emergency department did not. In this study, the incidence of fetal death was increased following direct uteroplacental fetal injury (100% of cases), maternal shock (67%), pelvic fracture (57%), severe head injury (56%), and hypoxia (33%). The adequacy of noninvasive maternal monitoring in assessing fetal well-being is challenged, and a discussion of diagnostic modalities for assessment for the injured gravida is set forth.

Accidents, Traffic↗