Pentobarbital coma in neurosurgical patients: nutrition considerations

Neurosurgical patients in pentobarbital coma are a complex nutrition support population. Physiologic changes associated with the primary injury to the brain, combined with the pharmacodynamic influences of barbiturate therapy, contribute to the difficulties of initiating aggressive nutrition support. Early nutritional repletion is important to the overall outcome of traumatically injured patients. Consequently, factors that influence nutrition support decisions must be understood to assure appropriate intervention. The metabolic changes associated with traumatic head injury, pentobarbital therapy, and nutrition support strategies are reviewed.

If something had gone wrong

If medical cover is not provided on a 24-hour-basis in small casualty departments it is essential that this is made clear to GPs, ambulance crews and nursing staff. Nurse practitioners must have a comprehensive training in the range of patients for whom the unit is designed and be aware of the limits of their competence. The patient should always receive the standard of care which he is entitled to expect from a reasonable practitioner following the approved accepted practice. The fact that the care is provided by a nurse rather than a doctor does not lower the standard. In determining whether a patient need to see a doctor, the doctor's availability should not be a criterion.

Nutritional and metabolic variables correlate with amino acid forearm flux in patients with severe head injury

OBJECTIVE

To measure the arterial-venous amino acid flux across the forearm muscle in patients with severe head injury.

DESIGN

Prospective, interventional study.

SETTING

Level I trauma hospital in the neurosurgery intensive care unit (ICU) at a university medical center.

PATIENTS

Eight nonsteroid-treated patients with severe head injury.

INTERVENTIONS

Patients were prospectively randomized to receive either standard or supplemental intravenous zinc therapy.

MEASUREMENTS AND MAIN RESULTS

Net forearm alanine, glutamine, tyrosine, phenylalanine, and branch-chain amino acid forearm flux were measured and compared with metabolic markers of energy expenditure and nitrogen excretion. There was a significant inverse relationship between the measured energy expenditure/predicted energy expenditure ratio and glutamine flux (r2 = .62; p < .05). The patients with the highest measured energy expenditure/predicted energy expenditure ratio had the greatest release of glutamine from forearm muscle. Nitrogen balance was significantly correlated with leucine flux (r2 = .53; p < .05) and with isoleucine flux (r2 = .67; p < .05). The patients with the most positive nitrogen balance had the least release of branch-chain amino acids from skeletal muscle. Tyrosine flux was highly correlated with net amino acid flux (r2 = .76; p < .01). Tyrosine flux was therefore indicative of overall muscle catabolism. Four patients had an overall negative flux of amino acids from skeletal muscle. Three patients had an overall negative flux of branch-chain amino acids.

CONCLUSIONS

This preliminary descriptive report suggests that increased skeletal muscle efflux of amino acids correlates significantly with metabolic variables of hypermetabolism and hypercatabolism in nonsteroid-treated, head-injured patients.

Transendoscopic electrocautery-induced gastric ulcers as a model for gastric healing studies in ponies

The ponies were apparently healthy and 6-20 months of age. In Study 1, gastric lesions were created by transendoscopic electrocautery in the non-glandular gastric mucosa, adjacent to the margo plicatus in 9 ponies which were then treated with water, 12 mg cimetidine HCl/kg bwt or 18 mg cimetidine HCl/kg bwt per os every 12 h for 35 days. In Study 2, gastric lesions were similarly induced in 9 ponies in the non-glandular mucosa and also in the glandular mucosa just below the non-glandular lesion on the greater curvature of the stomach. The ponies were treated with water, 8 mg cimetidine/kg bwt or 16 mg cimetidine/kg bwt per os every 8 h for 21 days. In both studies gastric lesion healing was monitored twice weekly by video gastroscopy. There was no apparent difference in healing times between the water and cimetidine treatment groups in either study. These results indicate that uniform gastric ulcers can be created by transendoscopic electrocautery in the non-glandular mucosa of ponies and that these ulcers heal at a predictable rate which should be useful in studying compounds that might accelerate healing of gastric mucosal lesions. However, cimetidine was not effective in accelerating the rate of healing under the conditions of this study.

Knowledge gain in a problem-based surgery clerkship

PURPOSE

To determine the magnitude of students' knowledge gain in a problem-based surgery clerkship and to identify the relationship of this gain to measures of clinical performance.

METHOD

Third-year students in a problem-based surgery clerkship at the University of Kentucky College of Medicine in 1990-91 were evaluated by a comprehensive set of objective measures: surgery subject examinations of the National Board of Medical Examiners (NBME) given as pretest and posttest to assess knowledge gain, two multiple-choice quizzes, a modified-essay examination, a standardized-patient examination, and an objective structured clinical examination (OSCE). The students were also evaluated by faculty tutors and preceptors and by their peers. NBME data were available for 66 students, and data were available on the other measures for 42 students. Statistical analysis involved two-way analysis of variance, single group t-test, Pearson correlations, and partial correlations.

RESULTS

The students' knowledge gain was statistically significant. The posttest mean score did not differ significantly from the national candidate mean of 500. All but two of the other knowledge and performance measures (the preceptor and tutor evaluations) correlated significantly with the knowledge gain score. The highest correlations were for peer evaluations, the standardized-patient examination, and the modified-essay examination. The overall reliability of the eight measures of student knowledge and performance was .81; deleting any measure, except the preceptor evaluation, lowered the reliability below the benchmark of .80.

CONCLUSION

The results suggest that a highly significant knowledge gain occurred during the problem-based clerkship and that this gain in knowledge was closely related to improved clinical performance.

Teaching anatomical pathology in an integrated self-directed learning programme: the Newcastle experience

In accordance with the teaching philosophy of the Faculty of Medicine at the University of Newcastle we attempt to "teach" Anatomical Pathology by directing the students' own learning. Thus we do not give a standard general and systematic pathology course. We aim to integrate pathology with other disciplines and in this we feel we are very successful. We use the small number of Fixed Resource Sessions to lay the foundations in basic pathology and to provide an overview of major areas for study. Further guidance is given in the form of Learning Goals. Clinico-Pathological Conferences are used extensively to highlight various areas. These sessions are supplemented by the wide availability of microscopy material and open access to autopsies. A high level of interest in Anatomical Pathology is exhibited by the medical students in the Faculty, as demonstrated by the large numbers who attend autopsies and who choose to undertake electives in Anatomical Pathology.

Optic nerve ganglioglioma. Case report

Gangliogliomas of the optic nerve are extremely rare. The case is reported of a 38-year-old man who presented with a visual field deficit and was discovered to have an optic nerve ganglioglioma. The possible embryological origins of this neoplasm, its histological and immunohistochemical features, and its appearance on magnetic resonance imaging are examined. The prognoses of optic nerve glioma and of gangliogliomas occurring elsewhere in the nervous system are compared.

Non-melanoma skin cancer: ten years of cancer-registry-based surveillance

The Tasmanian Cancer Registry carried out population-based surveillance of non-melanoma skin cancer (NMSC) from 1978 to 1987. A total of 8,651 NMSC were recorded in 7,160 individuals, representing an age-standardized rate of 161/100,000 per year. Ninety-four percent of cases were based on histological diagnosis. Incidence of basal-cell carcinoma (BCC) was higher than the incidence of squamous-cell carcinoma (SCC). The incidence of NMSC was twice as high in men as in women. Incidence increased substantially with age, more markedly for SCC than BCC. For most body sites, BCC was more frequent, but on highly exposed sites such as the backs of hands, lower limbs in women and ears in men, the incidence of SCC was higher. There was an overall increase of 7% per year in the age-standardized incidence rate of NMSC. The increase was more marked for BCC than for SCC, and was consistent across age groups and both sexes. A first NMSC during the study period was associated with a 12-fold increase among men and a 15-fold increase among women in the risk of development of a new NMSC within 5 years, when compared with the NMSC incidence recorded for the population as a whole.

Babies provide focus for quality improvement team

The challenge of quality improvement (QI) is to take its principles and tools and apply them to active problems in the clinical laboratory. The authors describe a 2-year QI project in which the staff of the laboratory and the neonatal care unit (NCU) significantly improved the care of babies who undergo heelsticks to provide blood samples for laboratory testing. Examples of quality tools used during the project are provided. The success of the QI project is due to the consistent and ongoing efforts of both staffs to care passionately about their customers--the babies of the NCU.

Vapors from collodion and acetone in an EEG laboratory

In the many EEG laboratories, the collodion-acetone technique has lost favor because of offensive vapors. We measured vapor concentrations of diethyl ether and acetone, the two principal vapors from this technique, to determine whether they reached toxic levels. We found that diethyl ether vapors usually reached the olfactory threshold, but acetone concentration did not. Neither reached concentrations that were systemically toxic. We then developed an inexpensive, effective method of reducing concentrated vapors during electrode application and removal and documented a significant reduction in vapor concentrations. With this information and with an inexpensive, "in house" vapor extraction system, technologist and patient satisfaction with the collodion method should greatly improve.

The ongoing development of a problem-based surgery clerkship: year three

The third-year clerkship at one college of medicine was modified to reflect an emphasis on adult learning principles and life-long learning habits. Problem-based learning was selected as the educational method, and the development of a cognitive knowledge base, clinical problem-solving skills, and appropriate clinical skills was stressed. At a yearly faculty education retreat, strengths and weaknesses of the clerkship were discussed. As a result of this meeting, several changes were made in the clerkship, including additional stress on students' usage of the medical library and computerized databases, a tutor development program, the addition of expert resource sessions, and more emphasis on students' development of clinical skills through a preceptor program. A comprehensive evaluation program designed to support the educational goals of the clerkship is in place. The major challenge of the program remains the proper synchronization of curricular, clinical, and student self-study activities essential for an ideal learning experience.

Undergraduate surgical education for the twenty-first century

This article addresses the problems associated with current undergraduate surgical education and discusses the requirements necessary for its improvement during the third and fourth years of medical school. It asserts that, coincident with the emphasis on faculty research and publication and expanded resident patient care duties, teaching, particularly medical student teaching, has assumed a very low priority. Third-year medical students are attached to surgical teams, where their education is haphazard and disorganized. Furthermore, because any teaching that occurs is teacher oriented rather than student centered, knowledge is accumulated passively and is not well retained. Traditional evaluation using shelf multiple choice examinations and ward ratings by residents and faculty may provide inaccurate assessments of the students' performance. The undergraduate surgical education program should be directed by a faculty member who has been grounded in educational techniques and research and supported by a department chairman committed to bettering the program. In the clerkship, medical students should be assigned to faculty rather than to services and should be presented problems that require solution. Students also should be provided with the resources to solve the problems and should be given sufficient time to solve them. Some operating room experience and bedside teaching should occur during the clerkship. A variety of evaluation and testing methods based on the learning objectives of the clerkship should be used. Third-year students should not be promoted until they have demonstrated their acquisition of appropriate knowledge and skills.(ABSTRACT TRUNCATED AT 250 WORDS)

Problem-based learning: an effective educational method for a surgery clerkship

Problem-based learning (PBL) has been implemented during the clinical years in a few medical schools. The purpose of this study is to determine whether PBL provides a better education than traditional methods. Students in the first and third rotations (n = 42) went through the traditional clerkship, which utilized Socratic teaching (SI), while students in the second and fourth rotations (n = 36) were taught by the PBL method. Two performance measures were used to assess clerkship effectiveness. One was a modified essay examination (MEE) administered as part of the departmental evaluation. The other was the NBME-II exam and its surgery subsection NBME-II-S. The MEE was designed to measure six dimensions of the problem-solving process. The NBME-II was utilized to measure knowledge. Unpaired t tests were used to identify statistically significant group differences. The PBL group performed significantly better on two MEE dimensions: (1) differential diagnosis formation (PBL, 92.5 +/- 0.8; SI, 89.1 +/- 0.5; P < 0.01) and (2) interpretation of clinical data (PBL, 93.3 +/- 0.6; SI, 91.6 +/- 0.4; P < 0.03). A third dimension, ordering appropriate lab and diagnostic studies, approached significance (P = 0.057), and the PBL group performed better. On the NBME-II there was not a significant difference between the two groups. However, the trend (P = 0.059) was for the PBL group to score higher on the NBME-II-S (PBL mean: 502 +/- 15; SI mean: 468 +/- 12). When overall achievement was controlled for, the PBL group performed significantly better than the SI group (P = 0.046) on the NBME-II-S.(ABSTRACT TRUNCATED AT 250 WORDS)

Interstate differences in incidence and mortality from melanoma. A re-examination of the latitudinal gradient

OBJECTIVE

To investigate the patterns of cutaneous malignant melanoma (CMM) mortality in Australia.

DESIGN

A descriptive analysis of melanoma incidence and mortality in Australia supplemented by a case series analysis of melanoma survival. Melanoma mortality rates were based on tabulations supplied by the Australian Bureau of Statistics for the years 1969-1989. Melanoma incidence rates were based on State cancer registry records for the years 1977-1990. The case series survival analysis was based on detailed individual records from the population-based cancer registries in Tasmania and South Australia.

MAIN OUTCOME MEASURES

The level of and rise in melanoma mortality rates during 1969-1989 in Australia; the five-year survival rates for Tasmanian and South Australian cases; and male:female incidence ratios related to latitude.

RESULTS

We found annual increases in melanoma mortality rates of 2.5% in men (P < 0.0001) and 1.1% in women (P < 0.0001) for all Australia. The five-year survival rates (with 95% confidence intervals [CI]) were: 67% (59%-75%) for Tasmanian men; 79% (76%-83%) for South Australian men; 80% (74%-86%) for Tasmanian women and 88% (86%-91%) for South Australian women. A change in the male:female incidence ratio with latitude was also found--women have significantly higher incidence rates at higher latitudes, but similar rates to men at lower latitudes.

CONCLUSIONS

The age standardised mortality from CMM for the period 1969 to 1989 shows little variation by State for women, despite a considerable range in latitude. CMM mortality in men is increasing at a faster rate than that in women. Between 1982 and 1987 the male:female incidence ratio in high latitudes in the Southern Hemisphere showed an excess of cases in women, a finding which we believe has not been reported before.

Nutrition and brain injury

The patient with head injury must overcome central and systemic insults. In addition to the head injury itself, the patient suffers a systemic metabolic response to injury. Both of these insults can affect the patient's ability to survive and recover. During the past decade, investigators have described the systemic metabolic result identified by hypermetabolism, hypercatabolism, the acute-phase response, decreased immunocompetence, hyperglycemia, increased counterregulatory hormone levels, increased ventricular fluid and serum cytokine levels, and altered gastric function. During the next decade, investigators will attempt to modulate this response by manipulating the types of nutrients administered, use of pharmacologic and physiological agents, and administration of growth factors.

Activation of the alternative complement pathway accompanies disease flares in systemic lupus erythematosus during pregnancy

OBJECTIVE

To assess the activity of systemic lupus erythematosus (SLE) during pregnancy and to distinguish it from preeclampsia.

METHODS

We prospectively measured the complement activation products Ba, Bb, SC5b-9, and C4d, as well as the conventional complement determinants C3, C4, and CH50, during pregnancy in 14 patients with SLE and 10 women with preeclampsia.

RESULTS

Four of the 14 SLE patients were considered to have disease flares, 3 occurring in the second trimester and 1 postpartum. In these patients, significant abnormalities of Ba, Bb, SC5b-9, and CH50 were noted. In contrast, measures of C4d did not distinguish between pregnant patients who had flares and those whose SLE remained stable. Although decreased values of C3 were rarely seen in the patients with stable disease, normal values of C3 during lupus pregnancy were not reliably associated with stable disease. Three of 10 non-SLE patients with preeclampsia had elevated levels of Ba; however, in each case, the CH50 level was close to or within the normal range. This was in sharp contrast to the findings observed in the 4 patients with active SLE, in whom high levels of plasma Ba were always associated with low CH50 values. Moreover, the ratio of CH50 to Ba was significantly lower in the patients with lupus flares than in the non-SLE patients with preeclampsia.

CONCLUSION

While a decline in the CH50 level alone could otherwise be attributed to decreased synthesis of complement components, these data demonstrate that ongoing activation of the alternative complement pathway can accompany disease flares in pregnant women with SLE.

Mutations in a nonconserved sequence of the Tetrahymena ribozyme increase activity and specificity

The RNA substrate-binding site of the Tetrahymena ribozyme is connected to the catalytic core by the joining region J1/2. Although J1/2 is not conserved among group I introns, small insertions or deletions in this sequence have dramatic effects, enhancing the turnover number and sequence specificity of ribozyme-catalyzed RNA cleavage. Measurements of rate constants for individual steps in the reaction have revealed the basis of these improvements. Ironically, the higher turnover and specificity both result from decreased affinity for RNA, rather than better cleavage. These results provide evidence that the nonconserved J1/2 sequence positions the RNA substrate to optimize tertiary interactions and ensure cleavage at the position corresponding to the 5' splice site. The wild-type RNA is well adapted to its biological function, and its limitations in multiple turnover can be corrected by mutation.

Increased plasma and ventricular fluid interleukin-6 levels in patients with head injury

The cytokine interleukin-6 (IL-6) plays a major role in initiating the acute phase response, especially in the production of acute phase reactants such as C-reactive protein. The objectives of this study were to determine whether plasma or ventricular fluid IL-6 levels were elevated at time of admission after head injury and whether plasma IL-6 levels related temporally to clinical improvement of levels of acute phase reactants. Thirty patients with Glasgow Coma Scale (GCS) scores of 3 through 10 were observed for 15 days after head injury. Peak elevation of plasma IL-6 occurred on admission (85 +/- 12 U/ml; normal level is less than 2 U/ml) and then decreased during the hospital course to a level of 29 +/- 4 U/ml on day 15. Plasma IL-6 levels decreased significantly faster in patients with admission peak 24-hour GCS scores of 8 through 10 compared with patients with GCS score less than 8 (p less than 0.01). Patients had markedly elevated and variable ventricular fluid IL-6 levels on admission (mean 3880 +/- 2022 U/ml; normal, less than 2 U/ml). A temporal relationship was found between plasma IL-6 levels and multiple acute phase reactants thought to be mediated by IL-6. We conclude that plasma and ventricular fluid levels of IL-6 are elevated after head injury and that plasma IL-6 level is temporally related to acute phase reactants and clinical improvement. We suggest that IL-6 may play an etiologic role in many of the metabolic or nutritional sequelae of head injury.

Update on sports nutrition

Adequate nutrition is vital to peak athletic performance. Insufficient energy and fluids can hinder ability to compete. Physicians and dietitians must emphasize nutrition's importance to athletes. Sports nutrition follows the same principles as good nutrition.

Ras mutations in United Kingdom examples of oral malignancies are infrequent

Point mutations in codons 12, 13 or 61 of the oncogenes Ha-ras, Ki-ras or N-ras have been identified in human malignancies of many types. Using the PCR (polymerase chain reaction) technique for DNA amplification in vitro and stringent probing of the amplified DNA on dot blots with a library of specific oligonucleotides, we have screened for the presence of ras mutations in oral and para-oral malignancies and some associated lesions. The material, from UK patients, consisted of 22 oral squamous-cell carcinomas including 5 neck metastases, 1 oral mucosal dysplasia, 1 proliferative verrucous leukoplakia, 1 antral and 1 tonsillar carcinoma, 1 basal-cell carcinoma, 1 salivary adenocarcinoma, 1 salivary adenoid cystic carcinoma and 1 lung adenocarcinoma metastatic to the gingiva. Genomic DNA was extracted from tissues which were fresh or preserved in liquid nitrogen. Two DNA samples contained point mutations in codon 61 of Ki-ras. One of these mutations was in the lymphocytes infiltrating a retromolar SCC. The other mutation (CAA to CAU; substitution of glutamine by histidine) was in the lung adenocarcinoma metastasis. The absence of ras mutations in the epithelium of primary oral squamous-cell carcinomas is of considerable interest as other work in our Department on Indian cases of oral carcinomas associated with chewing tobacco (quid) revealed that 35% of these had a codon 12, 13 or 61 mutation in Ha-ras. While ras activations arising from point mutations may occur in a high proportion of oral malignancies associated with chewing tobacco (quid), this was not the case in UK oral malignancies, even where tobacco was smoked.

Altered gastric emptying in the head-injured patient: relationship to feeding intolerance

Most patients with moderate to severe head injury initially do not tolerate enteral feedings postinjury. This intolerance is more prolonged than that found in patients suffering other types of trauma. The authors prospectively evaluated 12 patients with moderate to severe head injury (Glasgow Coma Scale score between 4 and 10) throughout their hospitalization for liquid gastric emptying as a possible mechanism for intolerance to enteral feeding. During Week 1, the majority of patients displayed a delay in gastric emptying. Patients also displayed an abnormal biphasic response (gastric emptying faster than normal during the early stage but prolonged later). By Week 2, many patients still had delayed and abnormal biphasic responses to gastric emptying. By Week 3, an improvement was observed with the majority of patients exhibiting rapid gastric emptying, but delays and abnormal biphasic responses were still seen. Patients who initially had rapid or normal gastric emptying tolerated full-strength full-rate feedings significantly earlier compared with those who experienced delayed gastric emptying (8.5 +/- 0.5 days vs. 13.7 +/- 3.2 days, p less than 0.001). All patients tolerated full-strength full-rate feedings by Day 16 postinjury (range 7 to 16 days) except the two patients who displayed delayed gastric emptying for prolonged periods of time (mean 25 days). This is the first study to longitudinally evaluate gastric emptying following head injury. The authors suggest that patients with moderate to severe head injury often experience alterations in gastric emptying which may affect their ability to tolerate enteral feedings.

Metabolic management of the patient with head injury

Patients with severe head injury have a disruption in metabolic homeostasis that includes increased energy expenditure and increased protein catabolism. These changes have been suggested to occur secondary to steroid administration, immobility, and other factors. A review of investigations indicates that the head injury itself causes these metabolic changes, although steroid administration can further alter plasma amino acid changes. Altered plasma amino acid profiles after head injury may have an effect on substrate availability to the brain, bacterial translocation, and overall nitrogen balance. Patients with severe head injury have increased skeletal muscle efflux of amino acids. Lack of nutrient supplementation in these patients is associated with increased morbidity and mortality. Enteral nutrition is the preferred mode of feeding but often is not tolerated in the patient with head injury. Parenteral nutritional support can be given to these patients without worsening cerebral edema.

C-reactive protein: a critical review

We have reviewed the literature to determine the value of C-reactive protein (CRP) measurements in the diagnosis and management of a wide range of conditions. CRP levels are of value in 6 clinical situations: (a) monitoring the response to antibiotic treatment in patients with known bacterial infections, (b) in obstetric patients with premature rupture of membranes, a rise in CRP can give early warning of intrauterine infections, (c) differentiation between active disease and infections in patients with systemic lupus and ulcerative colitis where the level of response to active disease has been previously established, (d) as a measure of disease activity and response to disease-modifying drugs in rheumatoid arthritis, (e) early detection of complications in postoperative patients, (f) in differentiating between infection and graft-versus-host-disease in bone marrow transplant patients. CRP levels have been used in an attempt to differentiate between bacterial and viral infections in various clinical situations, however the published literature does not support this role.

Daunorubicin coupled to monoclonal antibodies via a cis-aconitic anhydride linker: biochemical and cytotoxic properties revisited

Daunorubicin (DNR) was coupled to monoclonal antibodies (Mab) reactive to breast tumor cells using the acid-labile linking agents cis-asonitic anhydride and two other non acid-labile analogs, glutaric anhydride and citraconic anhydride. The acid derivatives of DNR formed by reaction with the anhydrides were converted to their N-hydroxysuccinimide (NHS) active esters for coupling to MAb. The molar input of drug NHS ester to MAb ranged from 1:1 to 100:1. The resulting MAb-DNR conjugates were purified by gel filtration and analyzed by high performance liquid chromatography. Monomeric conjugates contained 0.2 to 11.0 moles of DNR/mole of MAb. No evidence of cell killing was observed up to a concentration of 10 micrograms/ml DNR bound to MAb, while DNR exhibited 50% killing of the breast tumor cell line MCF-7 at a concentration of 1 microgram/ml.

Brain injury and nutrition

This review has discussed the current status of metabolic alterations and demands, nutrient administration, and nutritional assessment of the head-injured patient. More work is necessary in all areas to further describe and ascertain the nutritional requirements of these patients. Future research in this area should involve specific nutrient requirement, modification of the acute-phase response, and possibly administration of growth factors.

The controllable lifestyle factor and students' attitudes about specialty selection

Questionnaires were distributed to 346 fourth-year students in nine medical schools. The students were asked to state their selected specialty and to rank the importance that each of 25 influences, listed as questionnaire items, had had in making their choice of specialty. Factor analysis showed that particular items were significantly associated with particular factors. The first factor emphasized perceived lifestyle (items in this category gave importance to remuneration, personal time, and prestige); the second factor emphasized cerebral activities and a practice orientation; and the third factor stressed altruistic values and attitudes. The authors classified the selected specialties into three groups: those characterized as having a non-controllable lifestyle (NCL), those with a controllable lifestyle (CL), and surgery. (CL specialties were defined as those that allow the physician to control the number of hours devoted to practicing the specialty.) Data were analyzed using factor analysis, and analysis of variance, and the Scheffé method. Analysis indicated that the perceived lifestyle factor was most closely associated with the responses of those students choosing CL specialties. Furthermore, this factor received the highest total loading of the three factors from all the students, thus indicating the level of interest in lifestyle factors. Responses to items that defined the cerebral and practice factor were highest from the group of students choosing CL specialties and lowest from the group choosing NCL specialties. The NCL students scored highest in the altruism factor and the CL students scored the lowest. The surgery and NCL groups were similar in attitude patterns, and both were substantially different in attitude patterns from those of the CL groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized trial of surgery in the treatment of single metastases to the brain

To assess the efficacy of surgical resection of brain metastases from extracranial primary cancer, we randomly assigned patients with a single brain metastasis to either surgical removal of the brain tumor followed by radiotherapy (surgical group) or needle biopsy and radiotherapy (radiation group). Forty-eight patients (25 in the surgical group and 23 in the radiation group) formed the study group; 6 other patients (11 percent) were excluded from the study because on biopsy their lesions proved to be either second primary tumors or inflammatory or infectious processes. Recurrence at the site of the original metastasis was less frequent in the surgical group than in the radiation group (5 of 25 [20 percent] vs. 12 of 23 [52 percent]; P less than 0.02). The overall length of survival was significantly longer in the surgical group (median, 40 weeks vs. 15 weeks in the radiation group; P less than 0.01), and the patients treated with surgery remained functionally independent longer (median, 38 weeks vs. 8 weeks in the radiation group; P less than 0.005). We conclude that patients with cancer and a single metastasis to the brain who receive treatment with surgical resection plus radiotherapy live longer, have fewer recurrences of cancer in the brain, and have a better quality of life than similar patients treated with radiotherapy alone.

Repeat cerebral pan-angiography in subarachnoid hemorrhage of unknown etiology

Cerebral pan-angiography was repeated in 24 patients with spontaneous subarachnoid hemorrhage confirmed by spinal fluid or computed tomography evidence after the initial pan-angiography was negative. Recent, long-term follow-up was also conducted. The pan-angiography was technically adequate and did not show vasospasm, both being causes of aneurysmal nonvisualization. No etiology was demonstrated on repeat study in all 24 patients. An additional three patients had only one study, but autopsy later confirmed lack of etiology for subarachnoid hemorrhage despite gross and microscopic serial sections. The mean duration of follow-up was 18.1 years and outcome was favorable. Our results suggest that repeat cerebral pan-angiography may not be indicated in the patient who has no further bleeding episodes and in whom the initial study was normal, technically adequate, and complete without evidence of vasospasm. Nonvisualization of a cerebral aneurysm is commonly proposed as the most likely cause of subarachnoid hemorrhage when angiography is normal following nontraumatic subarachnoid hemorrhage. Our results suggest this conclusion is no longer accurate if the angiogram is technically adequate with the absence of vasospasm.

Specificity for 3',5'-linked substrates in RNA-catalyzed RNA polymerization

The finding that ribozymes can catalyze RNA chain elongation has led to the proposal that an early self-replicating system could have consisted of RNA alone. In such a chain elongation reaction, the Tetrahymena ribozyme was found to select 3',5'-linked substrates from a pool that contained a large molar excess of 2',5'-linked dinucleotides. The enzyme neither reacted with nor was inhibited by 2',5' phosphodiester linkages. The ability to exclude incorrectly linked substrates would have conferred an important selective advantage to a primordial RNA molecule with RNA replicase activity.

Brain death and the persistent vegetative state: similarities and contrasts

Brain death and the persistent vegetative state (PVS) share the following features: 1.) There is death of neurons in the brain; 2.) Both require an etiology which is capable of causing neuronal death. 3.) The potential for cognition is totally and permanently lost; 4.) Intensive medical support is usually withdrawn. In contrast, the diagnosis of brain death depends on death of the brainstem, while PVS implies permanent and total loss of forebrain function. While brainstem death can be diagnosed clinically, accurate prognosis in PVS requires additional investigation. Thus far, the EEG is the most specific test of neuronal function in the cerebral cortex. Brain death is equivalent to death, while PVS is not; management of the latter is more complex because of medical, social, ethical and legal factors.

Relationship between admission hyperglycemia and neurologic outcome of severely brain-injured patients

Severe head injury is associated with a stress response that includes hyperglycemia, which has been shown to worsen outcome before or during cerebral ischemia. To better define the relationship between human head injury and hyperglycemia, glucose levels were followed in 59 consecutive brain-injured patients from hospital admission up to 18 days after injury. The patients who had the highest peak admission 24-hour serum glucose levels had the worse 18-day neurologic outcome (p = 0.01). Patients with peak 24-hour admission glucose levels greater than 200 mg/dL had a two-unit increase in Glasgow Coma Scale score while patients with admission peak 24-hour serum glucose levels less than or equal to 200 mg/dL had a four-unit increase in Glasgow Coma Scale score during the 18-day study period (p = 0.04). There was a significant relationship between 3-month and 1-year outcome and peak admission 24-hour serum glucose level (p = 0.02 and p = 0.02, respectively). Those patients with admission peak 24-hour serum glucose levels less than or equal to 200 mg/dL had a greater percentage of favorable outcome at 18 days, 3 months, and 1 year than those with admission peak 24-hour glucose levels greater than 200 mg/dL (p = 0.0007, p = 0.03, and p = 0.005, respectively). A significant relationship between admission peak 24-hour Glasgow Coma Scale score and 18-day, 3-month, and 1-year outcomes was found (p = 0.0001, p = 0.0002, and p = 0.0002, respectively). Patients with mean admission peak 24-hour Glasgow Coma Scale scores of 3.5, 6, and 10 had mean admission 24-hour peak serum glucose levels of 252 +/- 23.5, 219.1 +/- 19, and 185.8 +/- 21, respectively (p = 0.05). These relationships were not significantly altered when confounding variables such as the amount of glucose given over the initial 24-hour postinjury period, the presence of diabetes or multiple injuries, and whether patients were given steroids, dilantin, or insulin were statistically incorporated. These data suggest that admission hyperglycemia is a frequent component of the stress response to head injury, a significant indicator of severity of injury, and a significant predictor of outcome from head injury.

Relationship of visceral proteins to nutritional status in chronic and acute stress

Visceral protein levels are used as indicators of prognosis, severity of injury, and nutritional status in hospitalized patients. Clinicians often use visceral protein levels to assess efficacy of nutritional support. The purpose of this study was to test the validity of such practices. Visceral protein levels were determined in patients in a medical ICU, head injury unit, and burn unit. The serum albumin and thyroxine-binding prealbumin (TBPA) levels correlated significantly with mortality in the medical ICU patients. Burn patients had depressed albumin and TBPA concentrations over the duration of hospitalization that related to the severity of thermal injury but not to adequacy of nutritional support. Head-injured patients had depressed admission albumin and TBPA levels, with neither protein level adequately related to caloric or protein supplementation. We conclude that visceral proteins may reflect severity of injury and prognosis in critically ill hospitalized patients, but they often do not accurately reflect nutritional status or adequacy of nutritional support.

Comparison of urinary urea nitrogen excretion and measured energy expenditure in spinal cord injury and nonsteroid-treated severe head trauma patients

Severe head trauma patients (HT) exhibit markedly elevated energy expenditure and 24-hr urinary urea nitrogen excretion (UUN) values. The objective of this study was to compare seven spinal cord injured patients (SCI) to seven HT for changes in UUN and measured energy expenditure (MEE) over the first 18 days following injury. Energy expenditure was measured by indirect calorimetry and compared to values predicted by the Harris Benedict Equation (PEE). There were six quadriplegics and one paraplegic in the SCI group. HT patients had peak Glasgow Coma Scale scores of 3 to 10 for the first 24 hr postinjury. Patients were studied prospectively and matched for age, sex, and admitting weight Week 1 following the injury, SCI had mean UUN values of 0.18 +/- 0.04 g/kg/day vs 0.18 +/- 0.01 for HT patients. The mean MEE/PEE ratio was 0.56 for the SCI and 1.4 for HT (p less than 0.01). Over the entire study period the mean UUN value for SCI was 0.23 +/- 0.03 g/kg vs 0.21 +/- 0.01 for HT. The mean MEE/PEE ratio for SCI was 0.94 while HT remained elevated at 1.5 (p less than 0.05). Although the UUN was comparable in SCI vs HT, there was a significant difference in MEE/PEE between the groups. The elevation in UUN observed in SCI is not due to a hypermetabolic state. This suggests that different mechanisms promote the increased nitrogen excretion observed in these two populations.