A multi-institutional analysis of complication outcomes after arteriovenous malformation radiosurgery

PURPOSE

To better understand radiation complications of arteriovenous malformation (AVM) radiosurgery and factors affecting their resolution.

METHODS AND MATERIALS

AVM patients (102/1255) who developed neurological sequelae after radiosurgery were studied. The median AVM marginal dose (Dmin) was 19 Gy (range: 10-35). The median volume was 5.7 cc (range: 0.26-143). Median follow-up was 34 months (range: 9-140).

RESULTS

Complications consisted of 80/102 patients with evidence of radiation injury to the brain parenchyma (7 also with cranial nerve deficits, 12 also with seizures, 5 with cyst formation), 12/102 patients with isolated cranial neuropathies, and 10/102 patients with only new or worsened seizures. Severity was classified as minimal in 39 patients, mild in 40, disabling in 21, and fatal in 2 patients. Symptoms resolved completely in 42 patients for an actuarial resolution rate of 54% +/- 7% at 3 years post-onset. Multivariate analysis identified significantly greater symptom resolution in patients with no prior history of hemorrhage (p = 0.01, 66% vs. 41%), and in patients with symptoms of minimal severity: headache or seizure as the only sequelae of radiosurgery (p < 0.0001, 88% vs. 34%).

CONCLUSION

Late sequelae of radiosurgery manifest in varied ways. Further long-term studies of these problems are needed that take into account symptom severity and prior hemorrhage history.

Postpyloric enteral feeding costs for patients with severe head injury: blind placement, endoscopy, and PEG/J versus TPN

This study describes the advantages and disadvantages of several forms of enteral nutrition for patients with severe head injury (Glasgow Coma Scale Score [GCS], <12). Included in the study are nasoenteric nutrition delivery using blind, endoscopic, percutaneous endoscopic gastrostomy (PEG) and PEG with jejeunostomy (PEG/J), and open jejeunostomy tube placement methods. These methods are compared with parenteral delivery of nutrition. The study constituted a retrospective analysis of the success rate of early enteral feedings by blind, endoscopic PEG and PEG/J and by open jejeunostomy placement of small-bowel feeding tubes for 57 patients with severe head injury. The delivery cost of enteral nutrition per intensive care unit day was compared to the delivery cost of parenteral nutrition per intensive care unit day in the same group of patients. Fifty-three percent of patients were adequately maintained nutritionally with nasoenteric delivery alone and did not require parenteral feeding. The average number of days for initiation of either enteral or parenteral feedings was 1.8 +/- 0.2 days from injury [standard error of mean (SEM); range, 0-10 days]. An average of 3.3 days (range, 0-23 days) was required for feeding tube placement in all patients. For 70% of patients, tube placement was completed within 48 h after injury. Full-strength, full-rate enteral feedings were achieved by a mean of 4.9 days after injury. A total of 128 feeding tubes were placed while the patients were in the intensive care unit (ICU; 2.2 +/- 0.2 tubes per patient). Blind placement of feeding tubes into the small bowel was rarely achieved without repositioning. Endoscopic tube placement into the duodenum was achieved in 50% of patients, into the jejunum for 33% of patients, and into the stomach for 18% of patients. While in the intensive care unit, patients received an average of 77 +/- 2% of their measured energy expenditure (range, 57-114%). Eleven percent of patients experienced severe gastrointestinal problems. Other problems were associated with the inability to achieve or maintain access: dislodged tubes (30%), clogged or kinked tubes (21%), and mechanical access problems (7 %). Seventy-one percent of patients in barbiturate coma were able to tolerate early nasoenteric feedings. Aspiration pneumonitis occurred equally among patients fed nasogastrically and those fed nasoenterically. The overall aspiration rate was 14%. The cost of acute enteral feeding was $170 per day and that for parenteral feeding, $308 per day. We conclude that blind transpyloric feeding tube placement is difficult to achieve in patients with severe head injury; endoscopically guided placement is a better option. Endoscopic feeding tube placement most consistently allows for early enteral nutritional support in severe head injured patients. Limitations include the inability to establish and/or maintain enteral access, increased intracranial pressure, unstable cervical spinal injuries, facial fractures, and dedication of the physician to tube placement and monitoring.

Aberrant expression of cyclin A and cyclin B1 proteins in oral carcinoma

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Aberrant expression of cyclin proteins has been found in a number of human cancers, including carcinomas of the head and neck, where amplification of the cyclin D1 gene is a common finding. The objective of this study was to examine cell cycle kinetics in oral carcinomas by determining the expression of the S phase protein cyclin A and the M phase protein cyclin B1. Routinely processed tissue sections of 50 oral squamous cell carcinomas from the floor of the mouth were stained by immunohistochemistry for cyclin A, cyclin B1 and Ki-67 proteins. Ten specimens of normal epithelium from the floor of the mouth were used as controls. The number of cells showing nuclear staining for cyclin A, cyclin B1 and Ki-67 proteins was determined by computer image analysis. There were 17 well-differentiated, 25 moderately differentiated and 8 poorly differentiated tumours. Mean counts for cyclin A (29.50+/-4.10, mean+/-95% CI), cyclin B1 (2.05+/-0.30) and Ki-67 (49.46+/-5.91) proteins in the carcinomas were significantly higher than counts for the normal epithelial controls (cyclin A: 9.30+/-1.72; cyclin B1: 1.01+/-0.36; Ki-67: 17.40+/-4.17). For cyclin A, cyclin B1 and Ki-67, mean staining scores for all tumour grades were significantly higher than controls. There was a strong correlation between Ki-67 and cyclin A scores in all tumour groups (r2=0.68); however, the correlations between cyclin B1 and cyclin A scores (r2=0.35) and between cyclin B1 and Ki-67 scores (r2= 0.39) were weak. We conclude that there is overexpression of cyclin A and cyclin B1 proteins in oral carcinoma. Furthermore, the poor correlations for cyclin B1 scores with other cell cycle indices suggest that there may be aberrant cell cycle progression at the G2/M checkpoint in oral carcinomas.

Estimation of energy expenditure from heart rate measurements in cattle maintained under different conditions

We examined whether heart rate (HR) could be used to estimate energy expenditure (EE) in cattle. Six Hereford heifers (345 +/- 10.8 kg BW) 12 mo of age were implanted with HR radio transmitters and maintained in individual pens under the following treatments: 1) shade or sun exposure, 2) high- or low-energy diet, and 3) feeding in morning or afternoon. The HR of animals was measured every .5 h during 3 mo; measurements of oxygen consumption and HR were made simultaneously in the morning and in the afternoon while animals were resting and exercising. Average daily HR (52 +/- 4 beats/min) and average daily EE (380 +/- 9 kJ/kg(.75)) in animals on the low-energy diet were less than values in animals on the high-energy diet (94 +/- 4 beats/min and 653 +/- 9 kJ/ kg(.75), respectively). For each animal and within each diet, linear regressions best described the relationship between HR and EE in resting animals, whereas quadratic regressions best described this relationship for exercising animals. The quadratic equation for the exercising animals could also be used for resting animals. In addition, a constant value of EE per heart beat (EE pulse) for each individual resting animal was found and gave accurate estimations. This method was convenient because 1) no exercise equipment was needed to generate the regression equations and 2) EE pulse was less affected by diet than was EE estimated by regression equations. We conclude that HR, a relatively easy measurement, can be useful and accurate in estimating EE. To increase the accuracy of the estimation of EE by HR, the relationship of HR to EE should be established for each animal. In addition, the nutritional regimen for the animal in which EE is estimated should be used for the animal in establishing the relationship.

Postoperative radiotherapy in the treatment of single metastases to the brain: a randomized trial

CONTEXT

For the treatment of a single metastasis to the brain, surgical resection combined with postoperative radiotherapy is more effective than treatment with radiotherapy alone. However, the efficacy of postoperative radiotherapy after complete surgical resection has not been established.

OBJECTIVE

To determine if postoperative radiotherapy resulted in improved neurologic control of disease and increased survival.

DESIGN

Multicenter, randomized, parallel group trial.

SETTING

University-affiliated cancer treatment facilities.

PATIENTS

Ninety-five patients who had single metastases to the brain that were treated with complete surgical resections (as verified by postoperative magnetic resonance imaging) between September 1989 and November 1997 were entered into the study.

INTERVENTIONS

Patients were randomly assigned to treatment with postoperative whole-brain radiotherapy (radiotherapy group, 49 patients) or no further treatment (observation group, 46 patients) for the brain metastasis, with median follow-up of 48 weeks and 43 weeks, respectively.

MAIN OUTCOME MEASURES

The primary end point was recurrence of tumor in the brain; secondary end points were length of survival, cause of death, and preservation of ability to function independently.

RESULTS

Recurrence of tumor anywhere in the brain was less frequent in the radiotherapy group than in the observation group (9 [18%] of 49 vs 32 [70%] of 46; P<.001). Postoperative radiotherapy prevented brain recurrence at the site of the original metastasis (5 [10%] of 49 vs 21 [46%] of 46; P<.001) and at other sites in the brain (7 [14%] of 49 vs 17 [37%] of 46; P<.01). Patients in the radiotherapy group were less likely to die of neurologic causes than patients in the observation group (6 [14%] of 43 who died vs 17 [44%] of 39; P=.003). There was no significant difference between the 2 groups in overall length of survival or the length of time that patients remained functionally independent.

CONCLUSIONS

Patients with cancer and single metastases to the brain who receive treatment with surgical resection and postoperative radiotherapy have fewer recurrences of cancer in the brain and are less likely to die of neurologic causes than similar patients treated with surgical resection alone.

Resistance mutations in protease and reverse transcriptase genes of human immunodeficiency virus type 1 isolates from patients with combination antiretroviral therapy failure

High-density oligonucleotide arrays were used to determine the sequence of the protease (PR) and reverse transcriptase (RT) genes of human immunodeficiency virus type 1 isolates from 35 patients in whom combination therapy that included a protease inhibitor had failed. Isolates had a median of three PR mutations (range, none to six). Three isolates had no known resistance mutations in PR. Twelve isolates (34%) had two or fewer resistance mutations in PR. The most commonly observed PR mutations were L10I, V82A/T/F, and L90M. No mutations were observed at codons 30 or 48. Mutations at RT codons 215 and 184 were observed in the majority of isolates. These data suggest that therapy can fail in some patients with relatively few PR resistance mutations. Clinical failure in the absence of resistance mutations implies inadequate drug exposure due to pharmacologic factors or suboptimal patient adherence to drug therapy.

Alpha1-acid glycoprotein concentrations and cerebrospinal fluid drug distribution after subarachnoid hemorrhage

STUDY OBJECTIVE

To test the hypothesis that changes in alpha1-acid glycoprotein (AAG) concentration alter central nervous system (CNS) drug distribution after subarachnoid hemorrhage.

DESIGN

Two-phase, prospective study.

SETTING

University-associated medical center.

PATIENTS

Twenty-one patients with subarachnoid hemorrhage.

INTERVENTION

In phase I, serum AAG concentrations of patients with subarachnoid hemorrhage were measured serially and compared with those in 21 controls undergoing elective neurosurgical procedures. In phase II, nimodipine was the pharmacologic probe to determine the relationship between drug distribution into the CNS and changes in AAG concentration.

MEASUREMENTS AND MAIN RESULTS

Serum and cerebrospinal fluid (CSF) samples were collected from patients with subarachnoid hemorrhage treated with nimodipine and used to measure total and unbound drug concentrations. Concentrations of AAG were 39% higher in patients than in controls preoperatively. They decreased significantly by 24 hours after surgery in patients and increased in controls. In both groups the concentrations were higher than reported normal values. During the period of reduced AAG concentration, calculated unbound nimodipine concentrations were 3-fold higher (p<0.05) than at later periods, with a trend toward higher total concentrations. Overall, mean CSF nimodipine concentration was 6.4% of mean serum total concentration. The CSF concentrations decreased as AAG concentrations increased, independent of serum concentrations (r = -0.52, p<0.02).

CONCLUSION

Concentrations of AAG change after subarachnoid hemorrhage and are transiently influenced by surgery. Unbound drug concentration increases when AAG concentrations decrease, whereas CSF concentrations decrease when AAG concentrations increase. These preliminary findings suggest that changes in AAG concentrations can alter unbound serum nimodipine concentrations and may affect CSF drug distribution.

Well-being and treatment satisfaction in older people with diabetes

OBJECTIVE

To measure well-being and treatment satisfaction and their correlates in older people with diabetes.

RESEARCH DESIGN AND METHODS

A postal survey was conducted of 1,000 diabetic patients aged > or = 60 years, representing 56% of the resident older diabetic population in an inner-city health district with a largely indigenous population of 230,000 people and a widely varied socioeconomic mix. Well-being and treatment satisfaction were measured with diabetes-specific instruments and correlated with patient data held in a central register.

RESULTS

There was an 81% response. The general well-being scores (median [interquartile range]) for patients on diet alone, tablets, and insulin were 54 (44-60), 53 (42-61), and 48 (35-56) (P < 0.001 comparing insulin with diet and tablets) compared with a scale maximum of 66. Treatment satisfaction scores were 35 (31-36), 35 (32-36), and 34 (30-36) (P < 0.001 comparing insulin with diet and tablets), scale maximum 36. Mean HbA1c concentrations were 5.0 +/- 1.4% (for patients on diet alone), 5.8 +/- 1.6% (tablets), and 6.6 +/- 1.7% (insulin) (P < 0.001 for each difference). Neither well-being nor treatment satisfaction correlated with HbA1c. Insulin-treated patients were younger and had been diabetic longer than non-insulin-treated patients; their well-being remained slightly, but significantly, lower when adjusted for age, sex, BMI, and diabetes duration, but treatment satisfaction was no longer significantly different. Women had lower well-being than men.

CONCLUSIONS

It has proved possible to measure well-being and treatment satisfaction in a large community-based samples of older people with diabetes. At the level of glycemic control in this population, neither parameter correlated with HbA1c. The lower well-being in insulin-treated patients remained significant in multivariate analysis.

A mixture model for sucking patterns of breast-fed infants

Previous studies of sucking patterns have mainly been on bottle-fed babies and have assumed that the babies' sucks occur within bursts separated by gaps of predetermined minimum length which is fixed over the feed. This study considers babies that are breast-fed, a more complex and natural process than bottle-feeding, and develops a more sophisticated model for the pattern of bursts and gaps which allows the parameters of the process to vary over the feed. We consider data from four breast feeds of each of 32 babies. We develop a two-component mixture model based on an underlying Markov chain model for the switching between bursts and gaps. We use the model to provide summary statistics for each feed and give estimates of the normal range of each of the model's parameters.

Priorities for values of adolescents in multicultural schools

The Rokeach Instrumental Values Survey was used to identify the priorities for instrumental values (desired ways to behave) of 172 adolescents in multicultural schools in Miami, Florida. The data are reported by grade, sex, and ethnicity.

Diverse presentation of aberrant origin of the right subclavian artery: two case reports

Aberrant origin of the right subclavian artery occurs in up to 1% of the population and can result in a wide range of symptoms. In this report, two cases of this anomaly are presented. In the first case, a patient developed fatal group A streptococcal aortitis. In the second case, the patient complained of chronic cough and intermittent dyspnea. The embryologic genesis of this abnormality is discussed and the current literature is summarized. Although relatively uncommon, it is important to consider this vascular anomaly in the differential diagnosis of patients with dysphagia, dyspnea, chest pain, fever, or mediastinal widening evidenced on chest roentgenography.

A phase I trial of neutron brachytherapy for the treatment of malignant gliomas

We performed a phase I trial to test the feasibility of neutron brachytherapy using californium-252 (252Cf) as the sole source of radiation, and to determine the maximum tolerable dose (MTD), for the treatment of malignant gliomas. Previous studies using external beam neutron radiation have shown that neutrons are capable of totally eradicating malignant gliomas. However, in most cases, fatal widespread radiation necrosis resulted. Radioactive implants are a logical method of increasing the dose to the tumour and decreasing the dose to normal brain. 252Cf is a relatively stable neutron-emitting isotope suitable for implant therapy. The study was an open ended dose-escalation study. All radiation was delivered by using only 252Cf implants, without external beam therapy of any type. The first dose step was 900 neutron cGy (ncGy); each subsequent step was increased by 100 ncGy. Three patients with newly diagnosed malignant gliomas were entered at each dose step, and the number was increased to six patients in dose steps at which necrosis of brain occurred. The study ended when two patients at any dose step developed radiation necrosis of brain outside the prescribed radiation field. 33 patients were entered into the study. 10 patients developed scalp necrosis associated with scalp doses above 900 ncGy. The study ended when two patients at the 1300 ncGy dose step developed radiation necrosis of brain. We conclude: (1) neutron brachytherapy using 252Cf as the sole source of radiation is a feasible treatment for malignant gliomas; (2) the scalp tolerates less neutron radiation than the brain; (3) the MTD (and the recommended dose for a phase II trial) of interstitial neutron brachytherapy is 1200 ncGy.

Using accreditation of prior learning and accreditation of prior experiential learning for entry on to the BSc in Medical Illustration

The Accreditation of Prior Learning (APL) and Accreditation of Prior Experiential Learning (APEL) scheme described in this paper has been prepared following discussions between the Institute of Medical Illustrators (IMI) and Glasgow Caledonian University (GCU), departments of Learning and Educational Development and Biological Sciences. The scheme gives specific academic credit under the Scottish Credit Accumulation and Transfer (SCOTCAT) scheme for learning gained from experience, allowing access onto the Bachelor of Science Degree (BSc) in Medical Illustration to potential students who do not have the required Higher National Diploma (HND) or equivalent entry qualification. The need, rationale and structure of the scheme are described.

Detection of somatic mutations of the bcl-2 oncogene in B cell lymphomas with the t(14;18)

The incidence of mutations within the first 582 bp of the open reading frame of the bcl-2 gene, has been investigated in presentation lymph node samples, from 7 cases with follicular non-Hodgkin's lymphoma (NHL), 1 case with centroblactic NHL, the DOHH, cell line derived from the immunoblastic transformation of a follicular NHL and one case with benign follicular hyperplasia. A total number of 43 point mutations within the examined portion of the bcl-2 gene were detected in the cases analysed including the DOHH, cell line. Similar analysis of peripheral blood lymphocytes from 2 normal individuals that lacked the t(14;18), revealed no mutations in one case and a single 101 bp A-->G transition in clone, in the other. Missense mutations were detected in 7/8 NHLs, the DOHH2 cell line and the case of benign follicular hyperplasia. There was a significantly higher frequency of mutations within the region corresponding to the BH1, one of the two known functional domains, of the bcl-2 protein. The same position, 445 bp of the bcl-2 gene, was found to be involved in missense mutations affecting the DOHH2 cell line and 3 cases with follicular NHL.

Intravenous insulin-like growth factor-I (IGF-I) in moderate-to-severe head injury: a Phase II safety and efficacy trial

The purpose of this study was to determine the effect of insulin-like growth factor-I (IGF-I) on the catabolic state and clinical outcome of head-injured patients. Thirty-three patients between the ages of 18 and 59 years with isolated traumatic head injury and Glasgow Coma Scale (GCS) scores of 4 to 10 were randomized to one of two groups. All patients received standard neurosurgical intensive care plus aggressive nutritional support; the patients in the treatment group also received intravenous therapy with continuous IGF-I (0.01 mg/kg/hour). During the 14-day dosing period, the control patients lost weight, whereas treated patients gained weight despite a significantly higher measured energy expenditure and lower caloric intake (p = 0.02). Daily glucose concentrations and nitrogen outputs were greater in control patients (p = 0.03) throughout the study period. During Week 1, only treated patients achieved positive nitrogen balance. Fifteen of 17 treated and 13 of 16 control patients survived the 1st week. No deaths occurred in patients whose serum IGF-I concentrations were higher than 350 ng/ml. Dichotomized Glasgow Outcome Scale scores for patients with baseline GCS scores of 5 to 7 improved from poor to good for eight of 12 treated patients but for only three of 11 control patients (p = 0.06). Eight of 11 treated patients with serum IGF-I concentrations that were at least 350 ng/ml achieved moderate-to-good outcome scores at 6 months, compared to only one of five patients with lower concentrations (p < 0.05). These findings indicate that pharmacological concentrations of IGF-I may improve clinical outcome and nitrogen utilization in patients with moderate-to-severe head injury.

Intravenous insulin-like growth factor-I (IGF-I) in moderate-to-severe head injury: a phase II safety and efficacy trial

The purpose of this study was to determine the effect of insulin-like growth factor-I (IGF-I) on the catabolic state and clinical outcome of head-injured patients. Thirty-three patients between the ages of 18 and 59 years with isolated traumatic head injury and Glasgow Coma Scale (GCS) scores of 4 to 10 were randomized to one of two groups. All patients received standard neurosurgical intensive care plus aggressive nutritional support; the patients in the treatment group also received intravenous therapy with continuous IGF-I (0.01 mg/kg/hour). During the 14-day dosing period, the control patients lost weight, whereas treated patients gained weight despite a significantly higher measured energy expenditure and lower caloric intake (p = 0.02). Daily glucose concentrations and nitrogen outputs were greater in control patients (p = 0.03) throughout the study period. During Week 1, only treated patients achieved positive nitrogen balance. Fifteen of 17 treated and 13 of 16 control patients survived the 1st week. No deaths occurred in patients whose serum IGF-I concentrations were higher than 350 ng/ml. Dichotomized Glasgow Outcome Scale scores for patients with baseline GCS scores of 5 to 7 improved from poor to good for eight of 12 treated patients but for only three of 11 control patients (p = 0.06). Eight of 11 treated patients with serum IGF-I concentrations that were at least 350 ng/ml achieved moderate-to-good outcome scores at 6 months, compared to only one of five patients with lower concentrations (p < 0.05). These findings indicate that pharmacological concentrations of IGF-I may improve clinical outcome and nitrogen utilization in patients with moderate-to-severe head injury.

Pain in 4- to 6-year-old children receiving intramuscular injections: a comparison of the Faces Pain Scale with other self-report and behavioral measures

OBJECTIVE

The main objective was to compare the utility of the Faces Pain Scale (Bieri et al., 1990) with three alternative self-report measures of pain intensity in children, as well as with pain ratings based on observations of the child's behavior.

DESIGN

Fifty children used 4 self-report scales to rate the severity of needle pain from routine immunization. Using videotapes, the child's pain-related behavior was coded in detailed fashion, and a subset of the sample were also rated globally by 60 registered pediatric nurses.

MAIN OUTCOME MEASURES

Faces Pain Scale; Poker Chip Tool; Visual Analogue Toy; Verbal Rating Scale; behavioral checklist (scoring observable facial, motor, verbal and vocal reactions).

RESULTS AND CONCLUSIONS

The Faces Pain Scale was simple to use, readily understood by the children, and showed a realistic distribution of scores with respect to the type of pain being measured. With the exception of verbal reactions (which were not meaningfully related to self-report), observer ratings based on detailed coding of the child's behavior correlated only poorly to moderately well with self-report scores (r = .39 to r = .58). Similarly, although confident in their judgments, the nurses' ratings showed only moderate agreement with those of the children. In estimating the child's pain, all observers appeared to appropriately weigh changes in the child's facial behavior, which showed evidence of being the most sensitive behavioral index to the intensity of short sharp (needle) pain in 4 to 6 years olds.

An analysis of perioperative surgical mortality and morbidity in the asymptomatic carotid atherosclerosis study. ACAS Investigators. Asymptomatic Carotid Atherosclerosis Study

BACKGROUND AND PURPOSE

Our aim was to determine the perioperative morbidity and mortality rates of patients in the surgical arm of the multi-institutional, prospective, randomized Asymptomatic Carotid Atherosclerosis Study (ACAS).

METHODS

Of 828 patients with carotid stenosis of 60% or more randomized to the surgical arm of ACAS, 721 underwent carotid endarterectomy (CEA). To qualify for participation, surgeons were required to have performed at least 12 CEAs per year with a combined neurological morbidity and mortality rate no greater than 3% for asymptomatic patients and 5% for symptomatic patients. Clinical centers had to demonstrate arteriographic morbidity less than 1% and mortality less than 0.1% per year. Primary events were stroke and death in the period between randomization and 30 days after surgery; secondary events were transient ischemic attack and myocardial infarction occurring in the same period.

RESULTS

Of the 721 patients who underwent CEA, 1 died and 10 others had strokes within 30 days (1.5%). Of the 415 who underwent arteriography after randomization but before CEA, 5 (1.2%) suffered transient ischemic attack or stroke caused by arteriography. Thus, a nearly equal risk of stroke was associated with both CEA and carotid arteriography. In addition, 6 transient ischemic attacks and 3 myocardial infarctions could be directly linked to CEA, for a total CEA event rate of 2.6%.

CONCLUSIONS

Patients with asymptomatic internal carotid artery stenosis exceeding 60% reduction in diameter who are acceptable candidates for elective operation may be considered for CEA if the combined arteriographic and surgical complication rates are 3% or less.

Functional organization of the hippocampal memory system

In humans declarative or explicit memory is supported by the hippocampus and related structures of the medial temporal lobe working in concert with the cerebral cortex. This paper reviews our progress in developing an animal model for studies of cortical-hippocampal interactions in memory processing. Our findings support the view that the cortex maintains various forms of memory representation and that hippocampal structures extend the persistence and mediate the organization of these codings. Specifically, the parahippocampal region, through direct and reciprocal interconnections with the cortex, is sufficient to support the convergence and extended persistence of cortical codings. The hippocampus itself is critical to the organization cortical representations in terms of relationships among items in memory and in the flexible memory expression that is the hallmark of declarative memory.

A step-wise protocol for stress ulcer prophylaxis in the neurosurgical intensive care unit

BACKGROUND

Neurosurgical patients are at risk for stress induced gastric erosion. Clinical criteria for monitoring stress ulcer prophylaxis (SUP) efficacy and predicting clinical bleeding are limited. SUP in the neurosurgical intensive care unit (NSICU) was evaluated utilizing a multidisciplinary quality assurance program with defined criteria for therapy.

METHODS

All patients admitted to the NSICU were managed using this protocol. Therapy was initiated with a single drug (cimetidine 300 mg IV every 6 hours, or continuous infusion up to 2400 mg/day) in 136 evaluable cases. Combination therapy was implemented if continued gastric pH < 4 and guaiac positive aspirates occurred (N = 45).

RESULTS

Significant correlations were observed between low gastric pH values and both GCS < 8 (P < or = 0.01) and length of ventilatory support (P < or = 0.005). Single agent therapy was more effective in patients with GCS > or = 8 (P < or = 0.001). Endoscopy was performed in 25 patients. No patient with GCS < 8 had pathologic lesions. The presence of asymptomatic gastrointestinal lesions was higher in patients requiring longer ventilatory support (P < or = 0.001) and intensive care unit stay (P < or = 0.0001). Patients requiring pentobarbital and vasopressors had statistically higher rates of clinical bleeding (P < 0.05). Patients with GCS < 8 had increased rates of pneumonia (P < or = 0.005) with a higher pneumonia rate when treated with combination therapy (P < or = 0.05). Overall, the incidence of clinical bleeding was 3.7%.

CONCLUSIONS

This protocol was effective for prospective monitoring of SUP efficacy and limited multiple drug therapy to patients at risk for clinical bleeding.

Postirradiated and nonirradiated gliosarcoma: immunophenotypical profile

BACKGROUND

Thirty-one gliosarcomas (25 nonirradiated and 6 postirradiated tumors) were selected based on the presence of two distinctive areas: a malignant gliomatous and a sarcomatous component. In all cases, the sarcomatous component appears like fibrosarcoma or malignant fibrous histiocytoma. Two tumors showed additional areas consisting of osteochondroid differentiation.

METHODS

All tumors were examined using antibodies against Ulex europaeus agglutinin I (UEA), glial fibrillary acidic protein (GFAP), vimentin (VM), epithelial membrane antigen (EMA), desmin, collagen IV, alpha-1-antitrypsin (alpha-1-AT) and smooth muscle actin (SMA).

RESULTS

While the VM highlighted the sarcomatous areas of all tumors there were only scattered spindle cells that were GFAP-positive in the same areas. The alpha-1-AT was diffusely reactive in the sarcomatous areas in 20 cases. Focal immunoreactivity was seen with SMA (20 tumors), UEA (8 tumors), EMA (5 tumors), collagen IV (5 tumors) and desmin (4 tumors) in the nonvascular sarcomatous cells.

CONCLUSIONS

The range of immunophenotypical expression is likely to be a reflection of the capacity of a multipotential progenitor to undergo divergent differentiation. There is a very little morphological difference between the postirradiated and nonirradiated tumors except that a higher proportion of postirradiated tumors are immunoreactive to SMA and desmin.

Analytical performance testing of an atrazine immunoassay system

A rigorous performance evaluation of an enzyme immunoassay (EIA) kit for the determination of atrazine in water samples was undertaken. Eleven individual batches of samples containing standards and spiked drinking waters were analysed and precision, bias and limit of detection were measured using statistical analysis. The technique was shown to be capable of achieving performance criteria (a total standard deviation of less than 5% or 2.5 ng, whichever is the greater) demanded of modern analytical systems and achieved a limit of detection of 9.2 ng l-1. There was no statistically significant bias measured for drinking water samples. Interference tests showed that the atrazine immunoassay was not significantly affected in the pH range 4.0-8.0 or by drinking water matrix components (anions, cations and chlorination by-products), even at their maximum allowable concentrations. There was a small extent of cross-reaction with simazine and atrazine degradation products, but given the persistence of atrazine, through its resistance to hydrolysis, breakdown products are likely to be present at much lower concentrations than the parent compound in drinking water. Simazine may potentially be more problematic, so it would be prudent to monitor a proportion of samples for simazine to determine the extent to which this may be contributing to the 'atrazine' measured in drinking water samples using the EIA kit.

Effects of pegorgotein on neurologic outcome of patients with severe head injury. A multicenter, randomized controlled trial

OBJECTIVE

To evaluate outcome of patients with severe closed head injury treated with pegorgotein, a scavenger of oxygen-derived free radicals.

DESIGN

Randomized, parallel, placebo-controlled, third-party-blind, multicenter trial, with a blinded, multicenter follow-up protocol.

SETTING

Twenty-nine centers in the United States.

PATIENTS

A total of 463 patients with severe closed head injury and a Glasgow Coma Scale score of 8 or less after resuscitation and stabilization.

INTERVENTIONS

Patients received a single intravenous dose of placebo, 10 000 U/kg of pegorgotein, or 20 000 U/kg of pegorgotein within 8 hours after injury.

OUTCOME MEASURES

The primary endpoint was the Glasgow Outcome Scale (GOS) score at 3 months after brain injury with GOS data trichotomized into good, fair, or poor outcome. Secondary efficacy endpoints included the Disability Rating Scale (DRS) and mortality. A secondary analysis was performed using GOS scores dichotomized into favorable and unfavorable outcomes. In a follow-up protocol at 6 months, GOS and DRS scores were again determined.

RESULTS

Of 463 patients randomized, 162 received placebo; 149, pegorgotein 10 000 U/kg; and 152, pegorgotein 20 000 U/kg. Treatment groups were comparable with respect to demographic characteristics, mechanism of injury, and time to treatment. Pegorgotein was well tolerated at both dose levels. At month 3, the trichotomized analysis found no significant statistical difference in neurologic outcome between the pegorgotein and the placebo groups. Although differences were not statistically significant, there were more favorable outcomes and no increase in the number of deaths or vegetative states among the patients given pegorgotein, more subjects had good or favorable outcomes with the 10 000-U/kg dose than with the 20 000-U/kg dose or placebo, and less disability was observed with the 10 000-U/kg dose than with either the 20 000-U/kg dose or placebo. No differences in mortality rate or cause of death were found between the 10 000-U/kg and placebo groups at either month 3 or month 6. The only statistically significant difference between the groups was a decreased incidence of adult respiratory distress syndrome in the 10 000-U/kg group as compared with the placebo group (P<.015).

CONCLUSIONS

In this clinical trial of 463 patients with severe head injury, no statistically significant difference in neurologic outcome or mortality was observed between patients treated with pegorgotein and those receiving placebo.

Demographics of brain metastasis

Brain metastases are the most common intracranial tumor, significantly out-numbering primary brain tumors. The apparent increase in the ratio of brain metastases to primary tumors may be the result of a number of factors, including the possibility of a CNS "pharmacologic sanctuary," an aging population, and improved imaging studies. Among adults, the most common origins of brain metastasis include primary tumors of the lung, breast, skin (melanoma), and gastrointestinal tract. Among patients under 21 years of age, brain metastases most often arise from the sarcomas and germ cell tumors.

The safety, tolerability, and pharmacokinetics of fosphenytoin after intramuscular and intravenous administration in neurosurgery patients

STUDY OBJECTIVE

To evaluate the safety, tolerability, and pharmacokinetic profile of fosphenytoin, a water-soluble phenytoin prodrug, after intramuscular and intravenous administration.

DESIGN

Open-label study of intramuscular administration, and double-blind, randomized study of intravenous administration.

SETTING

Six and ten hospitals throughout the United States for the intramuscular and intravenous multicenter studies, respectively.

PATIENTS

Neurosurgical patients who required anticonvulsant prophylaxis or treatment.

INTERVENTIONS

In the intramuscular study, 118 patients received loading doses ranging from 480-1500 mg phenytoin equivalents (PE) and daily maintenance doses ranging from 130-1250 mg PE for 3-14 days. In the intravenous study, 88 patients received fosphenytoin and 28 received phenytoin sodium for 3-14 days. Mean +/- SD loading doses and maintenance doses of intravenous fosphenytoin and phenytoin were 1082 +/- 299 mg PE and 411 +/- 221 mg PE, and 1082 +/- 299 mg and 422 +/- 197 mg, respectively. Trough phenytoin concentrations were measured daily in all patients.

MEASUREMENTS AND MAIN RESULTS

Intramuscular fosphenytoin was safe and well tolerated, with no irritation found for 99% of all injection site evaluations. Adverse events associated with the drug occurred in 9% of patients, commonly those typical of the parent drug. For intravenous treatment, the frequency of mild irritation at the infusion site was significantly lower in the fosphenytoin group (6%) than in the phenytoin group (25%, p < 0.05). Reductions in infusion rates were required in 17% and 36% of fosphenytoin and phenytoin recipients, respectively. No significant difference was observed relative to adverse events or seizure frequency between the groups. Trough plasma phenytoin concentrations were approximately 10 micrograms/ml or greater in patients receiving at least 3 days of intramuscular and intravenous fosphenytoin. Trough phenytoin concentrations were similar between patients receiving intravenous phenytoin and fosphenytoin on all study days.

CONCLUSION

Fosphenytoin can be administered intramuscularly and intravenously in neurosurgical patients to achieve and maintain therapeutic phenytoin concentrations for up to 14 days. Both routes are safe and well tolerated. Intravenous fosphenytoin is significantly better tolerated than intravenous phenytoin sodium in this patient subset.

Kaposi's sarcoma versus bacillary angiomatosis

Persons with acquired immune deficiency syndrome (AIDS) are subject to a host of pathologic entities secondary to a depressed immune system. Kaposi's sarcoma frequently presents in this immunocompromised population and, therefore, diagnosis seems clinically straightforward. However, because of the prevalence of a strikingly similar infectious disease known as bacillary angiomatosis, skin biopsy of one or more lesions is crucial.

Nuclear genes associated with a single Brassica CMS restorer locus influence transcripts of three different mitochondrial gene regions

Previous studies have shown that the mitochondrial orf224/atp6 gene region is correlated with the Polima (pol) cytoplasmic male sterility (CMS) of Brassica napus. We now extend this correlation by showing that the effects of nuclear fertility restoration on orf224/atp6 transcripts cosegregate with the pol restorer gene Rfp1 in genetic crosses. We also show, however, that the recessive rfp1 allele, or a very tightly linked gene, acts as a dominant gene, designated Mmt (modifier of mitochondrial transcripts), in controlling the presence of additional smaller transcripts of the nad4 gene and a gene possibly involved in cytochrome c biogenesis. A common sequence, TTGTGG, maps immediately downstream of the 5' termini of both of the transcripts specific to plants with the Mmt gene and may serve as a recognition motif in generation of these transcripts. A similar sequence, TTGTTG, that may be recognized by the product of the alternate allele (or haplotype), Rfp1, is found within orf224 just downstream of the major 5' transcript terminus specific to fertility restored plants. Our results suggest that Rfp1/ Mmt is a novel nuclear genetic locus that affects the expression of multiple mitochondrial gene regions, with different alleles or haplotypes exerting specific effects on different mitochondrial genes.

Prediction of outcome in patients with anoxic coma: a clinical and electrophysiologic study

OBJECTIVE

To evaluate and compare the predictive powers of clinical examination, electroencephalography (EEG), and studies of short-latency somatosensory evoked potentials in determining the prognosis in anoxic coma.

DESIGN

Prospective case series of patients in anoxic coma, whose prognoses were uncertain based on previously established clinical criteria. The clinical features, EEG, and somatosensory evoked potentials results were correlated with outcome.

SETTING

A 40-bed intensive care unit in a university teaching hospital.

PATIENTS

Thirty-four consecutive patients admitted over a 2-yr period with anoxic coma as the principal diagnosis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-seven (79%) patients never recovered consciousness and seven (21%) patients made a good recovery. One of six patients whose pupillary reflexes were present but whose other cranial nerve reflexes were absent on day 1 recovered, but none of the seven patients with these features still present on day 3 survived. None of the patients with motor responses of extension to painful stimuli or worse on days 1 or 3 recovered. The EEGs were classified into benign, uncertain, and malignant categories. The results of both EEG and somatosensory evoked potentials studies were strongly associated with outcome. With malignant EEG, the sensitivity was 74%, the specificity was 71%, and the positive predictive value was 90% [corrected] for the prediction of no recovery (death or persistent vegetative state). However, two patients with an initially malignant EEG eventually made a good recovery. The sensitivity for low amplitude or absent somatosensory evoked potentials for prediction of no recovery was 66%. There were no falsely pessimistic predictions with somatosensory evoked potentials, as all 18 patients with absent or low-amplitude responses had no recovery (specificity and positive predictive value were 100%). EEG and somatosensory evoked potentials studies were complementary to clinical examination in the determination of prognosis. Using a combined clinical and electrophysiologic approach, 63% of patients who had no recovery could be identified by day 3. Repeat EEG and somatosensory evoked potentials studies were of value in patients whose prognoses were uncertain, as their evolution invariably correlated with outcome.

CONCLUSIONS

Based on the present data and a literature review, we propose that clinical examination combined with the results of EEG and somatosensory evoked potentials can be used to establish an early, definitive prognosis in a significant proportion of patients in anoxic coma. On day 3 or thereafter, patients with motor response of extension to pain or worse and malignant EEG, or those patients with flexor posturing or worse and bilaterally absent cortical somatosensory evoked potentials invariably have poor outcome. However, some patients with initially malignant EEG and normal somatosensory evoked potentials may recover and should be supported until their prognoses become more definitive.

Effectiveness of individual and dyadic training protocols: the influence of trainee interaction anxiety

The present study focuses on the consequences of the social dynamics that are created whenever two or more individuals are brought together for the purpose of training. An investigation of the role of individual differences in interaction anxiety on training outcomes demonstrated that the comparative effectiveness of dyadic versus individual protocols for computer-based training is moderate by trainees' level of interaction anxiety. Specifically, assignment to a dyadic protocol adversely affected the performance of high-interaction-anxiety participants but appeared to be advantageous for low-interaction-anxiety participants. Implications are discussed for changing the design and implementation of computer-based protocols for training groups and individuals in military and industrial training centers.

Surgical results: a justification of the surgeon selection process for the ACAS trial. The ACAS Investigators

PURPOSE

The selection of surgeons to participate in a prospective randomized trial comparing the efficacy of a surgical method with medical management is critically important because it will have a direct impact on the outcome of the study and the future use of the operation. We report the success of the method used for selecting surgeons who participated in the Asymptomatic Carotid Atherosclerosis Study (ACAS) by examining the surgical morbidity and mortality rates and the outcome of the study.

METHODS

A Surgical Management Committee established criteria for auditing surgeons who wished to participate in the study. The parameters included a minimum performance of at least 12 carotid endarterectomies (CEA) per year and an audit of each surgeon's last 50 consecutive CEAs with required documentation of a combined neurologic morbidity and mortality rate of <3.0% for asymptomatic patients and <5.0% for all indications including symptomatic patients.

RESULTS

As of February 1991, 164 surgeons from 48 medical centers applied for ACAS participation. One hundred seventeen were approved, and their aggregate experience of 5641 operations yielded a combined neurologic morbidity and mortality rate of 2.3% for asymptomatic and symptomatic patients combined. The morbidity and mortality rate for CEA on asymptomatic patients was 1.7%. These surgeons, plus those recruited after February 1991, became investigators in the ACAS trial and were responsible for the surgical care of 825 patients who were randomized to the surgical arm. Seven hundred twenty-four patients actually underwent CEA. One patient (0.14%) died and ten patients (1.38%) had strokes within the 30-day perioperative interval, for a combined stroke or death incidence of 1.52%. The 5-year stroke event rate in the surgical group (including perioperative morbidity and mortality rates) was 5.1%. compared with 11% of patients treated medically, yielding a relative risk reduction of 53% in favor of surgery (p=0.004).

CONCLUSIONS

A method for selecting surgeons for participation in the ACAS trial was successful in providing low perioperative morbidity and mortality rates. This materially influenced the outcome of the study in favor of CEA.

Narcolepsy secondary to fourth ventricular subependymoma

BACKGROUND

Secondary (symptomatic) narcolepsy is rare. We report a subependymoma of the fourth ventricle associated with narcolepsy. The patient was a 50-year old woman with a long history of narcolepsy who died of colonic carcinoma with no cerebral metastasis. She was positive for HLA-DR2. At autopsy there was a tumour dorsal to the fourth ventricle which involved the midbrain tectum and rostral pons. Histologic examination of the tumour confirmed it to be a subependymoma.

METHODS

Review of the previous cases of secondary narcolepsy was made with particular reference to the anatomical location of the lesions.

RESULTS

Most of the lesions were found around the third ventricle and rostral brainstem.

CONCLUSIONS

Knowing the anatomical localization of the pathological changes in secondary narcolepsy could be important in improving our understanding of its pathogenesis.

Zinc supplementation is associated with improved neurologic recovery rate and visceral protein levels of patients with severe closed head injury

Sixty-eight patients were entered into a randomized, prospective, double-blinded controlled trial of supplemental zinc versus standard zinc therapy to study the effects of zinc supplementation on neurologic recovery and nutritional/metabolic status after severe closed head injury. One month after injury, the mortality rates in the standard zinc group and the zinc-supplemented group were 26 and 12%, respectively. Glasgow Coma Scale (GCS) scores of the zinc-supplemented group exceeded the adjusted mean GCS score of the standard group at day 28 (p = 0.03). Mean motor GCS score levels of the zinc-supplemented group were significantly higher on days 15 and 21 than those of the control group (p = 0.005, p = 0.02). This trend continued on day 28 of the study (p = 0.09). The groups did not differ in serum zinc concentration, weight, energy expenditure, or total urinary nitrogen excretion after hospital admission. Mean 24-h urine zinc levels were significantly higher in the zinc-supplemented group at days 2 (p = 0.0001) and 10 (p = 0.01) after injury. Mean serum prealbumin concentrations were significantly higher in the zinc-supplemented group (p = 0.003) at 3 weeks after injury. A similar pattern was found for mean serum retinol binding protein level (p = 0.01). A significantly larger number of patients in the standard zinc group had craniotomies for evacuation of hematoma; thus a bias may have been present. The results of this study indicate that zinc supplementation during the immediate postinjury period is associated with improved rate of neurologic recovery and visceral protein concentrations for patients with severe closed head injury.

Histopathology of the lung following intratracheal challenge with live Pseudomonas aeruginosa in intestinally immunized rats

This paper examines the histology of rat lungs following intestinal immunization with killed mucoid Pseudomonas aeruginosa and subsequent pulmonary challenge with live P. aeruginosa. The lungs of non-immune challenged rats developed a confluent haemorrhagic pneumonitis with degeneration and sloughing of the mucosa of the airways; perivascular infiltration with mononuclear cells was apparent 1-2 h post-challenge; some neutrophils were present by 2 h post-challenge; by 12 h post-challenge oedema and intra-alveolar haemorrhage were prominent and Gram-negative organisms were seen in large quantities. In contrast, immunized challenged animals showed a pronounced neutrophilic response 1-2 h post challenge; by 12 h post-challenge patchy abscesses were apparent with resolving inflammation and no organisms visible. The findings suggest that intestinal immunization prevents the development of fatal P. aeruginosa infections in the lung by accelerating the recruitment of polymorphonuclear neutrophils.

Characterization of a t(10;11)(p13-14;q14-21) in the monoblastic cell line U937

Previous analysis of the monoblastic cell line U937 has shown that several sublines contain a rearranged chromosome arm 11q. In order to determine the true nature of the rearrangement, fluorescence in situ hybridization (FISH) was carried out with various combinations of single copy anonymous markers, clones containing genes, a chromosome 10 paint, and an 11 centromere specific sequence. The rearrangement was deduced to be a reciprocal translocation between chromosomes 10 and 11 described as t(10;11)(p13-14;q14-21). The breakpoint on chromosome 11 is telomeric to the INT2 gene and the pHS11 probe at 11q13, and centromeric to the marker D11S36 localized to 11q14.3-q22.1 and the MLL gene at 11q23. Similar translocations have been reported in various acute leukemias, principally of the monocytic lineage, and also in T-cell precursor acute lymphocytic leukemias. Further characterization of the genetic rearrangements in U937 may lead to the isolation of genes important in leukemogenesis and provide an in vitro system for their study.

Colorectal carcinomas show frequent allelic loss on the long arm of chromosome 17 with evidence for a specific target region

Allelic loss is a common mechanism of inactivation of tumour-suppressor genes in colorectal carcinomas. A number of known or putative tumour-suppressor genes including NF1, BRCA1, NME1, NME2 and prohibitin are present on the long arm of chromosome 17, and this region has not been extensively analysed in colorectal tumours. In this study 72 colorectal carcinomas were examined for allelic loss at eight loci on chromosome 17. Allelic loss was frequent both at the p53 locus, which is known to be important in colorectal carcinoma, and also telomeric to p53 on 17p. Allelic loss continued to be present in more than 50% of cases in the pericentromeric region and on proximal 17q to the marker LEW101 (D17S40) at 17q22-23. The most telomeric markers on 17q showed lower rates of allelic loss. Analysis of cases with partial deletions which did not include the p53 locus showed a common region of overlap of the deletions centred on D17S40. This suggests the target of allelic loss on 17q is a tumour-suppressor gene in this region.

3D conformal radiotherapy in the sagittal plane for centrally located thoracic tumors

One hundred patients, recently treated at the University of California, San Francisco (UCSF) with radiotherapy for lung and esophageal cancer, were studied. Three subsets of these patients were defined based on tumor location to test how commonly the use of three-dimensional (3D) conformal radiotherapy (3DCRT) could improve significantly the delivery of high dosages. Comparisons were made between isodose distributions and dose volume histograms (DVHs) of patients' prior computed tomography (CT)-based treatment plans and newly generated 3D-based treatment plans. The use of beam angles outside the conventional horizontal plane did not significantly improve the dose distribution for patients if a peripheral mass was the target volume. Patients with a target volume involving the central thorax represented a subset (> 40% of the patients) who would have benefited the most from the use of nonconventional beam angles. In these patients, sagittal coplanar beams (sagittal Y technique) reduced the dose to 30% of the lung volume from 30% to 5%. Doses to the spinal cord and heart were slightly higher than with conventional techniques but were within the tolerance of normal tissues. The sagittal Y technique allows an escalation in total dose to the tumor without increasing dose to normal tissues beyond their tolerance.

Modulation of experimental mesangial proliferative nephritis by interferon-gamma

The observation that interferon-gamma (IFN-gamma) inhibits cell proliferation and collagen synthesis of a variety of cell types in culture has suggested that IFN-gamma may be useful in the treatment of fibroproliferative diseases. We administered recombinant IFN-gamma subcutaneously (10(5) U/kg/day for 3 days) to rats, beginning one day after the induction of mesangial proliferative nephritis with anti-Thy 1 antibody. IFN-gamma reduced glomerular (primarily mesangial) cell proliferation by 44% at days 2 and 4 compared to vehicle injected control rats with anti-Thy 1 nephritis (that is, proliferating cells that excluded the macrophage marker, ED-1, P < 0.001). Despite the inhibition of mesangial cell proliferation, IFN-gamma did not reduce the overall extracellular matrix deposition (by silver stain) or deposition of type IV collagen or laminin (by immunostaining) at 4 or 7 days, and glomerular type IV collagen and laminin mRNA levels were increased (1.4 and 1.7-fold) at 4 days relative to controls. The inability of IFN-gamma treatment to reduce mesangial matrix expansion may relate to the fact that IFN-gamma treated rats had a twofold increase in glomerular macrophages (that is, ED-1 positive cells, P < 0.001 at 2 and 4 days) with an increase in oxidant producing cells (day 2, P < 0.05) and a 1.6-fold increase in glomerular TGF-beta mRNA expression (4 days). This suggests that the effect of IFN-gamma to inhibit mesangial cell proliferation in glomerulonephritis may be offset by the ability of IFN-gamma to increase glomerular macrophages and TGF-beta expression. These data also show that IFN-gamma can partly dissociate the mesangial proliferative response from the extracellular matrix expansion in glomerulonephritis.

Cytokines and metabolic dysfunction after severe head injury

Patients with head injury must overcome central as well as peripheral metabolic insults. In addition to specific tissue damage to the brain, a cellular biochemical cascade occurs that can negatively affect organ function, cause a systemic response to injury, and may cause secondary tissue injury. The metabolites involved in this cascade are numerous and complex. Cytokines are important cell-to-cell communication mediators during injury. It is speculated that cytokines, such as interleukin 1 (IL-1), interleukin 6 (IL-6), tumor necrosis factor (TNF), and interleukin 8 (IL-8), which are found in elevated amounts in both human and basic trials after head injury, play a role in the cellular cascade of injury. Some of the metabolic events produced by small doses of cytokine infusion in animals, as well as humans, include fever, neutrophilia, muscle breakdown, altered amino acid metabolism, depression of serum zinc levels, production of hepatic acute phase reactants, increased endothelial permeability, and expression of endothelial adhesion molecules. These are all known sequelae of severe head injury. Cytokines have also been implicated in organ failure. Infusion of cytokines in basic science trials revealed that organ functions of the gut, liver, and lung are negatively altered by high-dose cytokine infusion. Infusion of certain cytokines has been shown to cause death of brain cells, increase blood-brain barrier permeability, and cause cerebral edema. This suggests that cytokines may also play a role in the sequelae of organ demise. These effects of cytokines have been attenuated in basic trials by blocking the initial signaling system of cytokines or by decreasing serum cytokine activity. We hypothesize that cytokines that are elevated after head injury play a role in the pathology of injury, including altered metabolism and organ demise.

Determinants of career choices among women and men medical students and interns

Women continue to be poorly represented in medical specialties other than general practice. A cross-sectional design was used to explore the development of career plans as medical training progressed; men and women students were compared in their first (n = 316), final (n = 295) and intern (n = 292) years. Women at each stage of training were significantly more likely to choose general practice as the field in which they were most likely to practise. There was little evidence that these differences were influenced by experience during training: women were as likely to choose general practice in first year as in the intern year. The most important determinant of career choice appeared to be the flexibility of training and of practice of medicine: variables such as the opportunity for part-time training, flexible working hours and part-time practice were important determinants of career choice and were of more importance to women than to men. The study also found high rates of discrimination or harassment reported by women medical students and interns. The results indicate the need for continued debate about these issues within medicine and the development of more flexible styles of medical training and practice.