Direct to Operating Room for Decompressive Craniotomy/Craniectomy in Patients With Traumatic Brain Injury

BACKGROUND

Emergent decompressive craniotomy/craniectomy can be a lifesaving surgical intervention for select patients with traumatic brain injury. Prompt management is critical as early decompression can impact traumatic brain injury outcomes.

OBJECTIVE

This study aims to describe the feasibility and clinical impact of a new pathway for transporting patients with severe traumatic brain injury directly to the operating room from the trauma bay for decompressive craniotomy/craniectomy.

METHODS

This is a retrospective cohort preintervention and postintervention study of severe traumatic brain injury patients undergoing decompressive craniectomy/craniotomy at a Midwestern U.S. Level I trauma center between 2016 and 2022. In the new pathway, the in-house trauma surgeon takes the patient directly to the operating room with the neurosurgery advanced practice provider to drape and prepare the patient for surgery while the neurosurgeon is en route to the hospital.

RESULTS

A total of 44 patients were studied, five (5/44, 11.4%) of which were in the preintervention group and 39 (39/44, 88.6%) in the postintervention group. The median arrival-to-operating room time was shorter in the postintervention cohort (1.4 hr) than in the preintervention cohort (1.5 hr). In examining night shifts only, the preintervention cohort had shorter arrival-to-operating room times (1.2 hr) than the postintervention cohort (1.5 hr).

CONCLUSION

The study demonstrated that the new pathway is feasible and expedites patient transport to the operating room while awaiting the arrival of the on-call neurosurgeon.

Outcomes of simultaneous versus staged intramedullary nailing fixation of multiple long bone lower extremity fractures

INTRODUCTION

Repair of multiple lower extremity long bone fractures with intramedullary nail (IMN) fixation is associated with significant cardiopulmonary burden and may result in mortality. These patients are at an increased risk for fat embolism syndrome, pulmonary embolism, Acute Respiratory Distress Syndrome (ARDS), and pneumonia. No standardized guidelines exist to guide treatment of these patients. Further, there is a paucity of data regarding the risk of simultaneous versus staged fixation of multiple long bone fractures that includes both tibial and femoral injuries, as patients with multiple concomitant fractures are often excluded from relevant analyses. Our level one trauma center aimed to identify whether simultaneous fixation, defined by definitive fixation of multiple lower extremity long bone fractures during one operative event, led to increased cardiopulmonary complications as compared to a staged approach, defined as multiple operations to reach definitive fixation.

PATIENTS AND METHODS

The Michigan Trauma Quality Improvement Program (MTQIP) database from 35 Level I and II trauma centers was queried to identify patients from January 2016 - December 2019. The primary outcome was incidence of cardiopulmonary complications for staged and simultaneous IMN fixation.

RESULTS

We identified 11,427 patients with tibial and/or femoral fractures during the study period. 146 patients met the inclusion criteria of two or more fractures treated with IMN fixation. 118 patients underwent simultaneous IMN fixation, and 28 patients received staged IMN fixation. There were no significant differences in injury severity score (ISS), demographics, pre-existing conditions, and cardiopulmonary complications between the two groups. There was a statistically significant difference in hospital length of stay (LOS) (p = 0.0012). The median hospital LOS for simultaneous fixation was 8.3 days versus 15.8 days for the staged cohort, a difference of 7.5 days.

CONCLUSION

This is the largest retrospective study to date examining simultaneous versus staged IMN fixation in patients with multiple long bone lower extremity fractures. In contrast to previous studies, we found no difference in cardiopulmonary complications. Given these findings, patients with multiple long bone lower extremity fractures should be considered for simultaneous IMN, an approach which may decrease hospital LOS.

Expecting the unexpected: incidental findings at a level 1 trauma center

INTRODUCTION

Incidental findings on comprehensive imaging in the adult trauma population occur at rates as high as 54.8%. We sought to determine the incidence of potentially malignant or pre-malignant incidental findings in a high-volume level 1 trauma center and to evaluate follow-up recommendations.

METHODS

This was a retrospective review of all patients with incidental findings on imaging who were admitted to the trauma service at our level 1 trauma center between January 1st, 2014, and October 1st, 2019. A multi-disciplinary team characterized findings as potentially malignant or pre-malignant.

RESULTS

The study included 495 patients who had incidental findings, 410 of whom had potentially malignant or pre-malignant findings on imaging, resulting in a cumulative incidence of 6.6%. The mean age was 65 and 217 (52.9%) patients were male. The majority of "incidentalomas" were discovered on CT imaging (n=665, 98.1%); over half were solid (n=349, 51.5%), while 27.4% were cystic (n=186) in nature. The lungs (n=199, 29.4%), kidneys (n=154, 22.8%), liver (n=74, 10.9%), thyroid gland (n=58, 8.6%), and adrenal glands (n=53, 7.8%) harbored the most incidentalomas. Less than half of patients with incidental findings received specific follow-up recommendations on the radiologist's report (n=150, 39%). Sixty-one percent of patients (n=250) had their incidentalomas detailed in the discharge paperwork.

CONCLUSION

The results of our study suggest that potentially malignant or pre-malignant incidental findings are common among trauma patients. Specific follow-up recommendations were not presented in 61% of the radiology reports, highlighting the need to standardize medical record capture of an incidentaloma to ensure adequate and appropriate follow-up.

Out of sight, out of mind? The impact on trauma patient opioid use when the medicine administration schedule is not displayed

INTRODUCTION

The impact of a visual pain medication schedule on opioid use among hospitalized trauma patients is unknown. We examined whether removal of this displayed schedule would decrease oral morphine equivalent (OME) use.

METHODS

This retrospective cohort study compared OME use in trauma patients in the inpatient setting before and after removing the patient-facing pain medication schedule that is typically displayed on the patient's white board for all trauma admissions.

RESULTS

707 patients were included. The control (n = 308, 43.6%) and intervention (n = 399, 56.4%) groups were similar in age (p = 0.06). There was no difference in total inpatient OME use between the control and intervention groups, median 50 (IQR: 22.5-118) vs 60 (IQR: 22.5-126), p = 0.79, respectively. No difference in total OME use was observed when patients were stratified by age, sex, race, ISS, and length of hospital stay.

CONCLUSION

Removing a visual display of the pain medication schedule did not decrease OME use in inpatient trauma patients.

Fall Risk Identification Throughout the Continuum of Care for Elderly Trauma Patients: An Injury Prevention Initiative

INTRODUCTION

Falls are the second leading cause of trauma-related deaths worldwide. Identifying fall risk patients and initiating interventions reduces injuries and mortality, particularly in the elderly. The primary aim of this retrospective study was to identify missed opportunities for fall risk identification and intervention for geriatric trauma patients.

PATIENTS AND METHODS

In this retrospective observational cohort study, the trauma registry was queried to identify geriatric patients admitted for a fall over 36 months. The electronic medical record (EMR) was reviewed to evaluate patients' fall risk in the 12 months prior to the index fall admission. The EMR was also queried for repeat falls within 12 months after discharge, and to determine if fall prevention education was provided at discharge.

RESULTS

597 patients met inclusion criteria; 68.3% were female. 64.7% were at risk for falling in the year before admission. 2% had documented fall prevention education at discharge. 32% of patients fell again within a year of discharge and 19.4% were readmitted for a repeat fall. Patients at high risk for falls (on the Hester-Davis scale) were significantly more likely to be readmitted (p = 0.005) and expire within six months (p = 0.033) than moderate risk patients. Mortality at 12 months post-admission for all patients was 19.4%.

CONCLUSION

This large study demonstrated that geriatric trauma patients admitted for a fall were already at risk for falling in the 12 months prior to admission. This is a novel finding that presents a substantial prevention opportunity for healthcare systems. Education and implementation of proven techniques to prevent falls as soon as at-risk patients are identified has the potential to change the course for a patient who may not only fall, but also fall again. This proactive approach could significantly impact the fall epidemic in our elderly population.

Ride the Wave: Continuous Electroencephalography is Indicated in the Management of Traumatic Brain Injury

Introduction: Patients with traumatic brain injury (TBI) are at risk for seizures and other abnormalities that can have permanent adverse effects on the brain. We aimed to report the incidence of seizures and continuous EEG (cEEG) abnormalities after TBI and identify any risk factors associated with the development of these abnormalities. Materials and Methods: This retrospective study identified 245 adult patients with mild to severe TBI who had a cEEG performed within one week of admission to a Midwest Level 1 Trauma Center between July 2014 and July 2019. Trauma registry and electronic medical record (EPIC) data were extracted. Results: Twelve percent of patients with TBI developed seizures and an additional 23% demonstrated electrographic patterns that are correlated with risk for seizures (such as lateralized periodic patterns and sporadic epileptiform discharges). Fifty three percent of seizures would have been missed unless a cEEG was performed. Age, history of epilepsy or prior TBI, hypertension, bleeding disorder, and dementia were associated with an increased risk of developing seizures or higher risk patterns. Conclusions: Thirty-five percent of patients who presented with TBI were noted to have seizures or electrographic patterns associated with a higher risk of seizures. The incidence of cEEG abnormalities in this study is higher than previously reported and these patients are at risk for permanent neurological injury. We recommend the routine use of cEEG for all critically ill patients with TBI as over half of the seizures would have been missed if cEEG was not employed.

Hotter Than It Looks: A Retrospective Review of Patients With Cholecystitis and With Negative Imaging

INTRODUCTION

Ultrasound is the gold standard for workup of cholecystitis in the emergency department, and findings heavily influence clinical decision-making. Patients with negative imaging for acute cholecystitis may be inappropriately sent home. The purpose of our study was to review the pathology and outcomes of patients presenting with biliary pain and negative ultrasound findings of acute cholecystitis.

MATERIALS AND METHODS

Emergency department patients who underwent laparoscopic cholecystectomy between January 2015 and February 2019 were reviewed retrospectively. Only patients with negative or equivocal imaging were included. The primary outcome was the incidence of cholecystitis on final pathology.

RESULTS

Two hundred fifty-seven patients underwent laparoscopic cholecystectomy. Pathology demonstrated cholecystitis in 84% of patients. Only 15% of patients had cholelithiasis without cholecystitis on pathology. The incidence of cholecystitis was similar in negative and equivocal imaging groups (84% versus 83%; P = 0.960). The median time from admission to the operating room was 12.1 h (interquartile range 7.1-18.3 h), and hospital length of stay was 1.2 d (interquartile range 0.8-1.7 d).

CONCLUSIONS

This study found that patients with negative or equivocal imaging had cholecystitis on pathology. On review of patient outcomes, those patients who underwent surgical intervention had a low rate of complications and short hospital stay.

Sumping's Up: A Multidisciplinary Educational Initiative on Gastric Drainage Tubes

BACKGROUND

Nasogastric tube placement is widely taught, and tube maintenance relies on astute nursing care with adherence to both institutional and evidence-based recommendations. However, precise adherence to current recommendations relies on knowledge base regarding the identification of malfunctioning gastric drainage tubes. Troubleshooting skills are crucial in maintaining patient safety and recognizing malfunction.

METHOD

Educational sessions on nasogastric and orogastric decompression tube management, led by a surgical intensive care fellow at a level 1 trauma center, were offered to critical care nurses. A presession and postsession survey evaluated the nurses' subjective and objective knowledge and comfort with naso/orogastric decompression tube management.

RESULTS

Ninety-seven critical care RNs participated. For all questions, the proportion of correct answers significantly increased from presession survey to postsession survey (p < .001). Ninety-seven percent of all participants found the session to be very helpful.

CONCLUSION

Physician-led educational sessions on naso/orogastric decompression tube management were well-received and improved subjective and objective measurements of nurses' knowledge and comfort level with gastric decompression tubes. [J Contin Educ Nurs. 2020;51(10):484-488.].

Rib Fracture Mortality: Are there clues in the core?

BACKGROUND

Sarcopenia is associated with increased morbidity and mortality in the trauma patient. The primary objective of this study was to determine the relationship of psoas cross sectional area with hospital mortality in patients with rib fractures over the age of 55 years.

MATERIALS AND METHODS

We retrospectively reviewed 1223 patients presenting to a Level 1 Trauma Center between 1/1/2002 and 1/31/2019. Psoas cross sectional area was measured using a polygonal tracing tool. Patients were stratified into four quartiles based on sex-specific values.

RESULTS

There was increased in-hospital mortality for patients with a lower psoas cross sectional area (10 %, 8%, 6%, and 4%, Q1-Q4 respectively; P=0.021). The logistic regression model determined for every increase in psoas cross sectional area by 1 cm² the odds of in-hospital mortality decreased by 4%.

CONCLUSIONS

In-hospital mortality is multifactorial; however, psoas cross sectional area may provide a clue in predicting adverse outcomes after traumatic rib fractures.

Are motorcycles really "donorcycles"? Examining organ donation rates between unhelmeted and helmeted motorcyclists

INTRODUCTION

Motorcycles are colloquially referred to as "donorcycles" among medical staff. However, the actual impact of helmet laws and helmet use on organ donation is unknown. Michigan's 35-year-old universal helmet law (UHL) was repealed in April 2012 and replaced by a partial-helmet law. We hypothesized that there would be an increase in organ donation rates from unhelmeted motorcyclist fatalities.

METHODS

Michigan's Gift of Life Michigan organ donation database was queried from April 2008 through May 2015 in conjunction with the Michigan Trauma Quality Improvement Program database from the same time period. All in-hospital motorcycle crash fatalities were examined.

RESULTS

A three-fold increase was found in the rate of organ donation for unhelmeted motorcyclists compared to helmeted motorcyclists (p = 0.006). Motorcycle crash fatalities tended to be younger in age after the UHL repeal with an average age of 32.8 years versus 40.8, however, this finding was not statistically significant (p = 0.071). Additionally, there was no significant difference in organ donation rates pre-UHL repeal (2008-2012) versus post-repeal (2012-2015).

CONCLUSIONS

This is the first study to demonstrate an increased rate of organ donation among unhelmeted motorcyclist fatalities compared to helmeted rider fatalities. There was no significant increase in the rate of organ donation following the Michigan UHL repeal. However, we identified that some motorcycle crash fatalities were from illegally unhelmeted riders in the past, prior to the repeal. Practical Application: Unhelmeted motorcyclists are three times more likely than helmeted riders to become organ donors, possibly due to the well documented increase in severe traumatic brain injuries in this population. From a public health perspective, helmets should be required for all motorcyclists and efforts to advocate in favor of helmet legislation should be supported by trauma systems and health professionals.

Association of Angiotensin-Converting Enzyme Inhibitors with Increased Mortality Among Patients with Isolated Severe Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) is associated with one-third of all deaths from trauma. Preinjury exposure to cardiovascular drugs may affect TBI outcomes. Angiotensin-converting enzyme inhibitors (ACEIs) exacerbate brain cell damage and worsen functional outcomes in the laboratory setting. β-blockers (BBs), however, appear to be associated with reduced mortality among patients with isolated TBI.

OBJECTIVE

Examine the association between preinjury ACEI and BB use and clinical outcome among patients with isolated TBI.

METHODS

A retrospective cohort study of patients age ≥ 40 years admitted to an academic level 1 trauma center with isolated TBI between January 2010 and December 2014 was performed. Isolated TBI was defined as a head Abbreviated Injury Scale (AIS) score ≥ 3, with chest, abdomen, and extremity AIS scores ≤ 2. Preinjury medication use was determined through chart review. All patients with concurrent BB use were initially excluded. In-hospital mortality was the primary measured outcome.

RESULTS

Over the 5-year study period, 600 patients were identified with isolated TBI who were naive to BB use. There was significantly higher mortality (P = .04) among patients who received ACEI before injury (10 of 96; 10%) than among those who did not (25 of 504; 5%). A multivariate stepwise logistic regression analysis revealed a threefold increased risk of mortality in the ACEI cohort (P < .001), which was even greater than the twofold increased risk of mortality associated with an Injury Severity Score ≥ 16. A second analysis that included patients who received preinjury BBs (n = 98) demonstrated slightly reduced mortality in the ACEI cohort with only a twofold increased risk in multivariate analysis (P = .05).

CONCLUSIONS

Preinjury exposure to ACEIs is associated with an increase in mortality among patients with isolated TBI. This effect is ameliorated in patients who receive BBs, which provides evidence that this class of medications may provide a protective benefit.

The danger zone: Injuries and conditions associated with immediately fatal motorcycle crashes in the state of Michigan

BACKGROUND

Immediately fatal motorcycle crashes have not been well characterized. This study catalogues injuries sustained in fatal motorcycle crashes and assesses the impact of crash conditions on injury patterns.

METHODS

Autopsy records from the office of the medical examiner of Kent County, MI and publicly available traffic reports were queried for information pertaining to motorcyclists declared dead on-scene between January 1, 2007, and December 31, 2016.

RESULTS

A total of 71 autopsies of on-scene motorcycle crash fatalities were identified. The two most prevalent injuries were traumatic brain injury (TBI) (85%) and rib fractures (79%). The majority of fatalities occurred in daylight hours (54.3%) and in a 55 mph speed limit zone (63.8%).

CONCLUSIONS

This study provides a catalogue of the injuries sustained in immediately fatal motorcycle crashes and the associated conditions. Advocacy efforts that highlight the risks associated with motorcycle riding and that promote safe riding practices are warranted.

Treadmill associated head injuries on the rise: an 18 year review of U.S. emergency room visits

OBJECTIVE

The treadmill is the most commonly used aerobic exercise equipment with studies showing many gym-related injuries are attributed to treadmills. The purpose of this study is to examine the incidence of treadmill-associated head injuries within the US.

METHODS

Retrospective data from 1997 to 2014 was collected via the National Electronic Injury Surveillance System, which provides annual es7timates of injuries associated with consumer products. Patients over 18 years who sustained treadmill-associated head injuries were included, and the estimated annual incidence was determined.

RESULTS

An estimated 4929 patients presented to US emergency departments with a head injury while exercising on a treadmill between 1997 and 2014. A >1000% increase in the number of head injuries was observed over the study period (p-value <0.001). Patients over 50 had a 14 times greater risk of admission than younger patients (p-value <0.001). Injuries were greater in women than men.

CONCLUSION

Our study demonstrates a significant increase treadmill-associated head injuries from 1997 to 2014. This phenomenon is most pronounced in older and female populations. The exact etiology of this large increase remains unclear. Education on the proper use of treadmills as well as further investigation into the cause of the increase are warranted.

Pre-injury polypharmacy predicts mortality in isolated severe traumatic brain injury patients

BACKGROUND

The use of 5 or more medications is defined as polypharmacy (PPM). The clinical impact of PPM on the isolated severe traumatic brain injury (TBI) patient has not been defined.

METHODS

A retrospective cohort study was performed at our academic level 1 trauma center examining patients with isolated TBI. Pre-injury medications were reviewed, and inhospital mortality was the primary measured outcome.

RESULTS

There were 698 patients with an isolated TBI over the 5-year study period; 177 (25.4%) patients reported pre-injury PPM. There were 18 (10.2%) deaths in the PPM cohort and 24 (4.6%) deaths in the non-PPM cohort (P < .0001). Stepwise logistic regression analysis revealed a 2.3 times greater risk of mortality in the PPM patients (P = .019).

CONCLUSIONS

Pre-injury PPM increases mortality in patients with isolated severe TBI. This knowledge may provide opportunities for intervention in this population.

The impact of tree-stand falls on a Level 1 trauma center in West Michigan

BACKGROUND

Falls from tree stands are common during the hunting season. We examined the impact of this injury mechanism on a Level 1 trauma center in West Michigan.

METHODS

Retrospective cohort study examining tree-stand fall patients between 2001 and 2013.

RESULTS

A total of 193 patients were included. Less than 3% of patients were wearing a harness. Falls from greater than 20 feet were associated with a higher injury severity score (P = .018). The injury severity score and Glasgow coma scale of the normal weight and overweight (OW) groups were the same. Overall 91.3% of normal weight patients were discharged home vs 63.5% of OW patients (P = .009). Median rehab stay was 12 days (3 to 92), and median charge was $24,048 (2,398 to 134,752).

CONCLUSIONS

Tree-stand falls cause significant injury, especially from heights greater than 20 feet. OW patients more frequently require rehabilitation. The infrequent use of safety harnesses is alarming.

A man with severe leg burns

A 52-year-old Hispanic male was transported to the emergency department after sustaining severe bilateral lower extremity burns in an electroplating factory. His examination revealed circumferential burns to the lower extremities with spotting in the perineum. The epidermis was stained green and sloughed off with gentle pressure. The underlying dermis was white and non-blanching, consistent with a full thickness burn. His feet were partially protected by his work boots where he had small areas of pink, blanchable, partial thickness burns (Fig. 1). Pertinent initial studies included a lactic acid level of 3.1 mmol/L and a creatinine of 1.02 mg/dL.

Recombinant factor VIIa (NovoSeven RT) use in high risk cardiac surgery

OBJECTIVE

The use of recombinant factor VIIa (rFVIIa) (NovoSeven RT(®)) to establish hemostasis during massive perioperative bleeding in cardiac surgery has been explored in several retrospective studies. While early results are promising, a paucity of data leaves many questions about its safety profile. We sought to further define its use and associated outcomes in a large cohort study at a single institution.

METHODS

A retrospective cohort study design was used, in which 236 patients received rFVIIa for bleeding after cardiac surgery. These patients were matched with a cohort of 213 subjects, who had similar operations during the same period of time. Primary end points included thrombo-embolic events, mortality, incidence of re-operation, use of blood products, and patient disposition at 30 days. Statistical significance was assessed at p < 0.05.

RESULTS

There was no statistically significant difference in the incidence of stroke (3.4%, 1.9%; p = 0.32), renal failure (8.5%, 7.0%; p = 0.57), or 30-day mortality (7.7%, 4.3%; p = 0.14) between the rFVIIa and the control groups, respectively. The rFVIIa group did experience a higher rate of re-operation for bleeding (11.0%, 1.9%; p = 0.0001) and had a two-fold increase in the use of each of the following: cryoprecipitate, fresh-frozen plasma, platelets, and packed red blood cells, relative to the control group (p < 0.00001).

CONCLUSIONS

rFVIIa is an effective hemostatic agent for intractable bleeding in high-risk cardiac surgery with an acceptable safety profile. rFVIIa does not appear to be associated with increased postoperative complications, including thrombo-embolic events and death.

Lactogenic immunity following vaccination of cattle with bovine coronavirus

In order to investigate the ability of an oil adjuvanted vaccine containing bovine coronavirus antigen to enhance lactogenic immunity in the calf, pregnant cows and heifers were vaccinated and specific virus neutralising antibody levels determined in serum, colostrum and milk. Pre-existing antibody titres (as a result of natural infection) in the serum of these animals were found to be significantly increased as a result of a single shot vaccination carried out between 2 and 12 weeks before calving. This was reflected in a similar increase in the titre and duration of specific antibody in milk and colostrum that was passed on to the calves. The overall response observed was highly dependent on an adequate antigen payload being incorporated within the single dose vaccine. No abnormal local or systemic reactions were observed as a result of vaccination. It is hoped that this approach will lead to the production of a superior commercial vaccine for the protection of neonatal calves against enteric coronavirus infection.

Wild isolates of murine cytomegalovirus induce myocarditis and antibodies that cross-react with virus and cardiac myosin

The laboratory-adapted K181 strain of murine cytomegalovirus (MCMV) induces both acute and chronic myocarditis, associated with autoantibodies to cardiac myosin, in susceptible BALB/c mice. However, the K181 MCMV strain has been maintained in the laboratory for many years and may not resemble naturally occurring strains of MCMV in its ability to induce myocarditis. Accordingly, six different isolates of MCMV from wild Mus domesticus were compared with K181 MCMV for their ability to induce myocarditis and autoantibodies to cardiac myosin in BALB/c mice. These isolates were shown to induce acute myocarditis similar to K181 MCMV, with associated focal and diffuse myocardial inflammation. However, the levels of myocarditis induced by the wild isolates during the chronic phase of the disease (days 32-56 post-infection) were low in contrast to the K181 strain. Interestingly, 30% of wild-trapped mice showed histological evidence of myocarditis and all were sero-positive to MCMV. Sera from BALB/c mice infected with wild MCMV isolates and from wild-trapped mice contained antibodies that cross-reacted with MCMV and cardiac myosin (S2 region). The cross-reactive region of MCMV was found to be a 50,000-55,000 MW viral polypeptide. These findings suggest that molecular mimicry may be involved in the pathogenesis of autoimmune myocarditis following infection with both laboratory and wild MCMV strains.

Incorporation of fludarabine and 1-beta-D-arabinofuranosylcytosine 5'-triphosphates by DNA polymerase alpha: affinity, interaction, and consequences

Fludarabine and 1-beta-D-arabinofuranosylcytosine (ara-C) are effective nucleoside analogues for the treatment of leukemias when used as single agents or together. Recent trials of the fludarabine and ara-C therapy with or without growth factors suggested an improved clinical response by combining fludarabine and ara-C. The activity of these antimetabolites depends on their phosphorylation to the respective triphosphates, F-ara-ATP and ara-CTP. The principal mechanism through which these triphosphates cause cytotoxicity is incorporation into DNA and inhibition of further DNA synthesis. A model system of DNA primer extension on a defined template sequence was used to quantitate the consequences of incorporation of one or two analogues by human DNA polymerase alpha (pol alpha). The template (31-mer) was designed so that DNA pol alpha incorporated six deoxynucleotides (alternately G and T) on the 17-mer primer, followed by insertion of an A and then a C. The primer was then elongated with G and T to the full-length product. The apparent Kms of DNA pol alpha to incorporate these analogues (0. 053 and 0.077 microM, respectively) were similar to the Km for dCTP (0.037 microM) and dATP (0.044 microM), suggesting that the enzyme recognized these analogues and incorporated them efficiently on the growing DNA primer. The velocity of extension (Vmax) of these primers ranged between 0.53 and 0.77%/min when normal nucleotides were present. Once inserted at the 3'-terminus, F-ara-AMP or ara-CMP were poor substrates for extension. However, in reactions lacking dCTP and dATP and with high concentrations of ara-CTP, ara-CMP was inserted by pol alpha after incorporation of the F-ara-AMP residue. This tandem incorporation of the two analogues resulted in almost complete inhibition (99.3%) of further extension of the primer. In the presence of competing deoxynucleotides, each analogue resulted in a dose-dependent inhibition of DNA synthesis. When present together, inhibition of the primer elongation was more than additive at low concentrations of analogue triphosphates. Based on these results and the intracellular pharmacokinetics of ara-CTP and F-ara-ATP in leukemia blasts, we propose a pharmacodynamic model to explain interactions between these analogues during combination chemotherapy.

Difluorodeoxyguanosine: cytotoxicity, metabolism, and actions on DNA synthesis in human leukemia cells

The success of gemcitabine (2',2'-difluorodeoxycytidine; dFdC) resulted in new interest in its purine congeners. Based on the structure-activity relationship studies of catabolism and anabolism, 2',2'-difluorodeoxyguanosine (dFdG) emerged as a lead candidate among the difluoropurine analogs. The cytotoxicity, metabolism, and actions of dFdG on DNA synthesis were studied in the human leukemia lymphoblastoid line CCRF-CEM. The IC50 values of dFdG after a 72-hour continuous incubation were 0.01, 0.03, and 0.28 mumol/L for CCRF-CEM, K562, and HL-60 cells, respectively. A cell line deficient in dCyd kinase was equally sensitive to dFdG, suggesting that, in contrast to dFdC, dFdG may be activated by other deoxynucleoside kinase(s). Consistent with these data, coincubation with dGuo spared the dFdG-mediated toxicity; however, up to 500 mumol/L dCyd failed to reverse the toxicity of dFdG. These observations indicated that dGuo kinase, which phosphorylates arabinosylguanine, also appears to play a major role in activating dFdG. CCRF-CEM cells incubated with varying concentrations of [3H]dFdG accumulated dFdGTP in a dose-dependent manner; a 3-hour incubation with 1 mmol/L dFdG resulted in more than 600 mumol/L intracellular dFdGTP. This is in contrast to the gemcitabine triphosphate accumulation, which is saturated at 10 to 20 mumol/L of exogenous dFdC. dFdG metabolites affected ribonucleotide reductase, resulting in a lowering of the dCTP pool; this is in agreement with the effect of dFdC on dNTP pools in leukemia cell lines. The major effect of dFdG on macromolecular synthesis was inhibition of DNA synthesis. DNA primer extension over a defined template revealed that dFdGTP was a good substrate for DNA polymerase alpha and incorporated opposite C sites of the template. Unlike arabinosyl analogs, but similar to gemcitabine triphosphate, dFdGTP incorporation caused DNA polymerase to pause after one normal deoxynucleotide was incorporated beyond the analog. The unique activation requirements of dFdG, its novel mode of inhibition of DNA synthesis, and its potent toxicity to human leukemia cells make it a promising new antimetabolite.

Cytotoxicity, metabolism, and mechanisms of action of 2',2'-difluorodeoxyguanosine in Chinese hamster ovary cells

The emerging clinical success of gemcitabine (2',2'-difluorodeoxycytidine) stimulated interest in the synthesis and evaluation of purine congeners. The cytotoxicity, metabolism, and mechanisms of action of the lead candidate, 2',2'-difluorodeoxyguanosine (dFdGuo), were studied in Chinese hamster ovary cells. Unlike the natural nucleoside deoxyguanosine (dGuo), dFdGuo was not a substrate for purine nucleoside phosphorylase. Wild-type Chinese hamster ovary cells and a mutant line deficient in deoxycytidine (dCyd) kinase were similarly affected by dFdGuo (50% inhibitory concentration, 7.5 and 6.5 microM, respectively), suggesting that unlike gemcitabine, dCyd kinase was not responsible for activation of dFdGuo. This was further confirmed by separation of nucleoside kinases (adenosine kinase, dGuo kinase, and dCyd kinase) of Chinese hamster ovary cells on DEAE-cellulose column chromatography. The kinase activity that phosphorylated dGuo also converted dFdGuo to its monophosphate, suggesting that dGuo kinase activated dFdGuo. Consistent with this result, coincubation with dGuo spared the dFdGuo-mediated toxicity; however, addition of up to 10 mM dCyd did not reverse the toxicity of dFdGuo. Intracellularly, dFdGuo was phosphorylated to its mono-, di-, and triphosphates; dFdGuo triphosphate (dFdGTP) was the major metabolite and accumulated to 45 microM after a 6-h incubation with 30 microM dFdGuo. The elimination of dFdGTP was monophasic with a t1/2 of about 6 h. Deoxynucleotides were decreased in cells incubated with dFdGuo, suggesting that ribonucleotide reductase was inhibited. dATP, which decreased 78% after a 4-h incubation with 30 microM dFdGuo, was most affected. dFdGuo was a potent inhibitor of DNA synthesis. Extension of a DNA primer over a defined template in the presence of dFdGTP revealed that dFdGTP was a good substrate for incorporation opposite C sites of the template by DNA polymerase alpha. dFdGTP incorporation caused DNA polymerase alpha to pause after the polymerization of one additional deoxynucleotide. This pattern of inhibition, which is shared by gemcitabine, distinguishes 2',2'-difluoronucleosides from arabinosylnucleosides which halt primer extension at the incorporation site. dGTP competed effectively with dFdGTP for incorporation by DNA polymerase alpha. The unique activation requirements and patterns of inhibition of DNA synthesis distinguish this promising new antimetabolite from other nucleoside analogues.

The physicochemical, immunological and biological properties of rat pituitary and plasma LH

A comparison was made between the properties of LH derived from female rat pituitary glands and plasma. Samples were collected from adult intact rats 5 h before or at the time of the pro-oestrous preovulatory LH surge; 27-day-old rats untreated or given 5 IU pregnant mares' serum gonadotrophin (PMSG) s.c. on day 25, which induced LH release 54 h later and adult ovariectomized rats untreated or primed with either 5 micrograms oestradiol benzoate s.c. or 5 micrograms oestradiol benzoate followed 48 h later by 0.5 mg progesterone s.c., which induced LH release 4-6 h later. All pituitary LH samples were totally bound to an anionic ion-exchange resin (DE52), while only a small proportion of the plasma LH was bound. Only 0-10% plasma LH obtained from intact, ovariectomized (with and without steroids) and untreated immature rats was bound, while a greater proportion of bound LH (36%) was noted in rats treated with PMSG. Gel filtration indicated only slight differences between pituitary and plasma LH, the former eluting marginally earlier than whole plasma and the unbound and bound plasma forms derived after separation by DE52 resin. Affinity chromatography (Concanavalin A and Glycine maximus) showed that LH from both sources possesses high mannose oligosaccharides and that plasma LH does not bear terminal N-acetyl galactosamine residues, although 20% of the pituitary form does. Plasma obtained from pro-oestrous rats had greater bioactivity than had pituitary LH in stimulating testosterone from Leydig cells and progesterone from granulosa cells in vitro, and inducing ovulation in immature rats in vivo. Leydig cell bioassays for LH in fractions obtained from ion-exchange separation indicate that steroidogenic activity of unbound plasma LH is greater than bound pituitary LH when they were collected at times of enhanced release. When release was inhibited (oestrogen-primed ovariectomized rats or immature rats), the steroidogenic activity of plasma and pituitary LH were similar and an acidic steroidogenic component was present in the plasma that was not recognized immunogenically as LH. In summary, pituitary LH undergoes a conversion on release into the plasma that involves a change in binding characteristics on an ion-exchange resin. In conditions when LH release is enhanced there is an increase in bioactivity of plasma LH owing to modification either by steroids or some other plasma factor(s) that perhaps influence the structure of LH directly or by steroids acting indirectly to alter GnRH release, which then modifies LH structure. These structural changes are minor and probably involve alterations in the glycosyl attachments.

A murine cytomegalovirus-neutralizing monoclonal antibody exhibits autoreactivity and induces tissue damage in vivo

The autoreactivity of murine cytomegalovirus (MCMV)-neutralizing monoclonal antibody (mAb) AC1 was examined in vitro and in vivo. Both mAb AC1 and a human antiserum reactive with U1-small nuclear ribonucleoprotein (U1-snRNP) stained uninfected mouse embryo fibroblasts (MEF) in a speckled nuclear pattern and reacted with 70,000 molecular weight (MW) MEF nuclear antigens by immunoblotting, suggesting that mAb AC1 cross-reacted with the 70,000 MW component of U1-snRNP. However, only mAb AC1 cross-reacted with an additional epithelial cytoplasmic autoantigen present in cultured HEp2 cells. On tissue sections from uninfected mice, mAb AC1 predominantly reacted with a component of central and peripheral nervous systems, although cross-reactivity with the stratum spinosum of the skin and the outer sheath of hair follicles was also observed. Immunoblotting revealed that mAb AC1 reacted with phosphorylated epitopes present on a 98,000 MW MCMV structural protein and the 200,000 MW mouse neurofilament protein (NFP). Treatment of uninfected mice with mAb AC1 resulted in a severe interstitial pneumonia with greatly thickened and congested alveolar septa. Severe oedema of the hypodermis and a mild mesangial proliferative glomerulonephritis were also observed. These results demonstrate that a mAb reacting with a MCMV structural phosphoprotein which can protect mice against the dissemination of MCMV, can also promote the development of autoimmune disease. Therefore, the production of such cross-reactive antibodies may be an important mechanism in the development of autoimmunity following viral infection.

Fatal hemothorax from mycotic celiac artery aneurysm

We present two cases of ruptured mycotic aneurysms infected with Staphylococcus aureus. Each patient had hemoptysis and in each case there was hemothorax caused by a ruptured mycotic aneurysm of the celiac artery. In case 1, the pathogenesis was transient Staphylococcus aureus septicemia infecting an atherosclerotic plaque with subsequent aneurysm formation and rupture. In case 2, the septicemia arose from an infected knee. The presentation of a celiac artery aneurysm as hemoptysis and as the cause of hemothorax is rare.

Stimulation of luteinizing hormone-Beta messenger ribonucleic Acid and post-translational modification of luteinizing hormone isoforms by second messengers mediating the action of gonadotrophin-releasing hormone

Abstract Several second messenger systems have been implicated in mediating the action of gonadotrophin-releasing hormone on the pituitary gonadotrophs and numerous studies have shown that activation of these systems induces luteinizing hormone (LH) secretion. However, it is not known how gonadotrophin-releasing hormone or the second messenger systems induce de novo LH biosynthesis and post-translational modification of the hormone. In these experiments hemipituitary glands have been perifused with drugs which activate second messengers or stimulate protein kinase C directly. The LH secretory responses have been correlated with measurements of common a and LHbeta mRNA and the molecular species of LH which were present in the pituitary perifusate after exposure to the drugs. Gonadotrophin-releasing hormone (50 ng/ml, 42 nM), with and without the presence of extracellular Ca(2+), the Ca(2+) ionophore, A23187 (10 muM), and phorbol 12-myristate (1 muM) all stimulated an increase in LHbeta mRNA compared with controls and the appearance of a different isoform of LH to that found stored in and released from the unstimulated pituitary gland. Phospholipase C was without effect on LHbeta mRNA levels and showed minimal efficacy in inducing the appearance of the different LH isoform.

Antigens recognized by the human immune response to severe leptospirosis in Barbados

Serum samples obtained from patients hospitalized in Barbados with severe leptospirosis were tested by the microscopic agglutination test (MAT), enzyme immunoassay (EIA) and immunoblotting with leptospires that had been isolated from these patients. While serum samples taken a few days after onset of symptoms often showed no apparent correlation between MAT and EIA, later sequential serum samples produced similar profiles in both tests during the course of infection. Immunoblotting sonicate from Leptospira interrogans serovars arborea, copenhageni and bim with patients' sera, revealed reactions with a number of bands that corresponded with outer envelope components. These components included lipopolysaccharide (LPS), flagella and other outer membrane proteins, in addition to a low-molecular-weight (MW) carbohydrate cross-reactive with members of the Leptospiraceae. IgM antibodies elicited in the first to second week after infection reacted mainly with LPS and the low-MW cross-reactive carbohydrate. Comparative analysis of isolates of the same serovar by sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting showed that while two serovar arborea isolates were identical, serovar bim isolates differed significantly from each other. This difference was also observed in comparative MAT testing.

Passive protection against infectious bursal disease virus by viral VP2 expressed in yeast

Infectious bursal disease virus (IBDV), a pathogen of major economic importance to the world's poultry industries, causes a severe immunodepressive disease in young chickens. Maternal antibodies are able to protect the progeny passively from IBDV infection. The gene encoding the IBDV host-protective antigen (VP2) has been cloned and expressed in yeast resulting in the production of an antigen that very closely resembles native VP2. When injected into specific pathogen free chickens a single dose of microgram quantities of the yeast derived antigen induces high titres of virus neutralizing antibodies that are capable of passively protecting young chickens from infection with IBDV.

Antigens recognized by the human immune response to vaccination with a bivalent hardjo/pomona leptospiral vaccine

Serum from volunteer subjects vaccinated with a bivalent whole cell vaccine of Leptospira interrogans serovar hardjo/serovar pomona grown in protein-free medium, was tested by the microscopic agglutination test (MAT), enzyme-immunoassay (EIA) and immunoblotting. Specific IgM antibodies to either serovars hardjo or pomona were detected in some subjects as early as 6 days after vaccination with peak antibody levels occurring 13-68 days after vaccination. Whereas all subjects produced specific IgM to both serovars, not all produced specific IgG to both serovars. Immunoblotting with hardjo sonicate revealed that all subjects produced IgM antibodies reacting with the 15, 23 and 28 kDa components of hardjo lipopolysaccharide (LPS), and most produced IgM antibodies that reacted with the 34.5 kDa flagellar doublet. In contrast, not all sera immunoblotted against pomona sonicate reacted with the 29 and 35 kDa components of pomona LPS. However all subjects produced antibodies reacting with a diffuse 14.4-27 kDa band. These antibodies appeared early in the immune response. Serum from the one vaccinated subject tested protected hamsters from acute lethal infection with serovar pomona.

Gonadotrophin glycosylation and function

This review emphasizes the heterogeneous structure of the gonadotrophin hormones and the influence of different oligosaccharide structures on the bioactivity of these hormones. A summary has been made of the changes in biopotency of the gonadotrophins throughout the life-cycle of the human and in different endocrine states in the rat. In general it appears that the charge of the gonadotrophin conferred by the acid radicals attached to the terminal groups on the oligosaccharide structures strongly influences biopotency. Basic structures have a greater potency in in-vitro assays, but a short half-life in the circulation, while acidic isoforms are less potent, but have a longer circulatory time and are thus more active in in-vivo estimations. More basic forms are secreted over the adult reproductive years compared with the prepubertal period and old age. The glycosyl structure of the carbohydrate groups also alters in different endocrine states and is probably also important for the bioactivity and potency of the hormone. Gonadotrophin-releasing hormone (GnRH) and gonadal steroids can influence the type of isoform synthesized and released, and therefore affect the function of gonadotrophins. GnRH enhances glycosylation, sulphation and biopotency. Oestradiol potentiates the glycosylation induced by GnRH and reduces sialylation, while testosterone increases sialylation.

Identification of leptospiral flagellar antigens by gel electrophoresis and immunoblotting

Flagella extracted from five serovars, representative of the pathogenic and saprophytic species of the Leptospiraceae, were morphologically similar. Analysis of Leptospira interrogans flagellar preparations by polyacrylamide gel electrophoresis revealed three common major bands in the (30-40) x 10(3)-mol. wt region, and serovar-specific bands in the lower region of the gels. Although some differences were observed, flagella extracted from L. biflexa serovar patoc and Leptonema illini revealed similar electrophoretic profiles to those seen in L. interrogans flagella. Immunoblot analysis showed that while flagellar components in the (20-30) x 10(3)-mol. wt region were recognised only by homologous rabbit antisera, a major protein doublet of (33-34) X 10(3)-mol. wt, depending on the species, was also demonstrated by heterologous antisera. The serovar-specific bands in the (20-30) x 10(3)-mol. wt region were composed of lipopolysaccharide (LPS). These results show that leptospiral flagella are immunogenic and contain antigens which are conserved among the different genera of the family Leptospiraceae.

Antigens recognised by the human immune response to infection with Leptospira interrogans serovar hardjo

Serum samples from patients infected with Leptospira interrogans serovar hardjo were tested by the microscopic agglutination test (MAT), enzyme immunoassay (EIA) and immunoblotting. There was no apparent correlation between MAT titre and EIA optical density (OD) for individual serum samples, but sequential serum samples produced similar profiles in both tests during the course of an infection. Immunoblotting of hardjo sonicate with patients' sera revealed reactions with a number of bands, in the mol. wt (10(3] range 14.4-95. However, all serum samples reacted with the major 28 x 10(3)-mol. wt sub-unit of hardjo lipopolysaccharide (LPS) and most reacted with a (34.5-35) x 10(3)-mol. wt flagella doublet. Examination of sequential serum samples obtained over a period of about 3 months after infection revealed little change in the antigens detected after the second to third week of infection. Absorption of patients' sera with whole viable leptospires revealed that antibodies to several exposed antigens, including LPS, were produced. Sera which reacted with hardjo flagella also reacted with bands of similar mol. wts in preparations from other serovars.

Effect of bromocriptine on LH pulsatility in the polycystic ovary syndrome

The effects were studied of bromocriptine, 10 mg daily for 1 year, on luteinizing hormone (LH) pulse characteristics in patients with classical polycystic ovarian syndrome (PCOS). All patients were hirsute, had been oligomenorrhoeic since menarche, had LH: FSH ratios of greater than 3:1, and either elevated serum testosterone (T) or dehydroepiandrosterone sulphate (DHAS) concentrations. In 10 subjects who completed the study menstrual frequency increased from an average of 3.6 to 8 per year but few of the cycles were ovulatory. Mean (SE) serum testosterone fell from 4.4 (0.5) nmol/l pretreatment to 2.8 (0.3) nmol/l (P less than 0.01) and DHAS from 7.9 (1.1) mumol/l to 5.4 (1.1) mumol/l (P less than 0.05). Serum delta 4 androstenedione and oestradiol did not change with bromocriptine treatment. Mean serum LH fell from 17.4 (2.4) IU/l to 11.2 (1.8) IU/l (P less than 0.03) after 12 months of bromocriptine. No pattern of LH pulsatility specific to PCOS was detected during 10 min sampling for an 8 h period prior to dopamine agonist treatment. LH interpeak interval (58 (5.2) min) and peak amplitude (156 (7.2%) of mean nadir) in untreated PCOS were similar to that of the mid-follicular stage of ovulatory cycles, and bromocriptine for 1 year did not alter these variables. We conclude that while bromocriptine reduces serum androgen levels and increases menstrual frequency it has no effect centrally to modify hypothalamic GnRH secretion. The reduction in LH levels by bromocriptine may be the result of diminished gonadotroph sensitivity to GnRH or reduced pituitary stores of LH available for release. Despite the return towards normal of various hormonal characteristics of PCOS, bromocriptine has little place in the management of this condition.

Genus-specific antigens in Leptospira revealed by immunoblotting

Immunoblotting of leptospiral sonicates with heterologous rabbit antisera revealed a distinct cross-reactive pattern which differed with respect to the pathogenic and non-pathogenic leptospiral serovars, and that all serovars tested from Leptospira interrogans, L. biflexa and L. illini contained a common 35 kilodalton (Kd) band. A leptospiral genus-specific antigen preparation produced by ethanol fractionation of L. biflexa serovar patoc reacted by enzyme immunoassay (EIA) with all heterologous serovars tested. Further purification using Sephacryl S-300 gel filtration revealed one major cross-reactive peak and several homologous peaks detectable by EIA. Gel electrophoresis of this peak revealed 3 major protein bands of 35, 34 and 29 Kd by Coomassie blue staining. This peak was further fractionated by high pressure liquid chromatography (HPLC), yielding 7 fractions, one of which cross-reacted. Rabbit antisera to this S-300/HPLC fraction reacted with all serovars tested. Immunoblotting revealed 2 distinct groups of cross-reactive antigens, a 33-35 Kd group that was proteinase K sensitive but not reduced by periodate oxidation, and a 14.4-26.5 Kd group whose activity was reduced by periodate but not proteinase K, indicating the presence of both protein and carbohydrate genus antigens. Immunoblotting L. interrogans serovar pomona flagella with S-300/HPLC antiserum suggested that the 35 Kd band found in all serovars tested was a flagellar component.

Peripheral vision and child pedestrian accidents

In both adults and children, peripheral vision is poorer than foveal vision, but there is evidence that detection in peripheral vision is relatively poorer in children than it is in adults. That may contribute to the particularly high pedestrian accident rates of children. Two laboratory experiments investigated peripheral vision in men and women and in boys and girls aged 7, 9 and 11. Using an array of stationary lights, Expt 1 examined reactions to apparent movement (the phi phenomenon) in mid and extreme periphery; and, using film sequences of a moving car, Expt 2 included a comparison of foveal and peripheral fields. Overall there was little evidence to support the hypothesis that children have poorer peripheral vision than adults relative to their foveal vision. Nonetheless there were some experimental differences: in Expt 1, 7-year-olds made fewer detections, particularly in the extreme periphery; and, in both experiments, detections tended to be slower. The relatively complex car movements in Expt 2 were detected faster in foveal than peripheral vision. There were no sex differences. Children detected more movements on the left. In Expt 2 these detections were faster, and children made relatively more simulated road crossings when the car approached from the left (all adults 'crossed' in all trials).

Glycosylation of human thyroglobulin and characterization by lectin affinity electrophoresis

Thyroglobulin, a 660 kDa glycoprotein, is the major product of protein synthesis in the thyroid gland. It has been suggested that modifications of thyroglobulin glycosylation occur in various thyroid disorders. In order to study possible changes in glycosylation of tissue thyroglobulin associated with thyroid disease, we have developed a lectin affinity electrophoresis system which allows characterization of small (less than 1 microgram) quantities of thyroglobulin. Human thyroglobulin was extracted and purified. Agarose gels were cast containing concanavalin A, Ricinus communis agglutinin, L-phytohaemagglutinin and pokeweed mitogen at various concentrations. Purified human thyroglobulin was serially diluted, loaded onto lectin gels and electrophoresed. Concanavalin A, R. communis agglutinin and phytohaemagglutinin all bound thyroglobulin in a concentration-dependent manner. Pokeweed mitogen did not bind thyroglobulin. Purified thyroglobulin was treated with neuraminidase and endoglycosidase H. Two-dimensional immunoelectrophoresis revealed the migration of thyroglobulin to be modified by neuraminidase but not by endoglycosidase H. Lectin affinity electrophoresis of purified human thyroglobulin with and without enzyme treatment indicated the presence of: oligomannose structures as shown by concanavalin A reactivity and modification by endoglycosidase H, and complex oligosaccharides as shown by affinity for R. communis agglutinin and modification by neuraminidase. These structures are in keeping with the proposed patterns of glycosylation of human thyroglobulin and indicate suitability of the method for characterizing the glycosylation of small quantities of thyroglobulin.

Natural and vaccine-related immunity to Streptococcus pneumoniae

To investigate the protective effects of pneumococcal vaccine, we assayed serum from healthy adults and from elderly bronchitics for antibody and opsonic activity against nine serotypes of S. pneumoniae. Before vaccination, there was no relation between opsonization and the level of antibody measured by RIA. Some serotypes were well opsonized in the absence of detectable antibody to capsular polysaccharide; others were not, despite modest levels of antibody. These in vitro studies did not support the concept that a certain level of antibody (e.g., greater than or equal to 250 ng of antibody nitrogen/ml) was specifically associated with the capacity to opsonize pneumococci. Nearly all postvaccination sera had increased antibody and opsonic activity against all serotypes, but the lack of correlation in any individual serum persisted. RIA showed that pre- and postvaccination levels of antibody in elderly adults with chronic lung disease were similar to those of younger adults. In elderly bronchitics, opsonizing activity for six of the nine serotypes was lower after vaccination, a result of suggesting a possible explanation for the failure of pneumococcal vaccine to be fully protective in these subjects. Elderly subjects had higher levels of antibody to phosphocholine, but when isolated, this antibody did not opsonize any of the vaccine strains of pneumococci. These results suggest that alternative strategies are needed to maximize the protective effect of pneumococcal vaccine in the population at greatest risk.

Emergence of bactericidal and opsonizing antibody to Vibrio vulnificus following bacterial infection

Virulent isolates of Vibrio vulnificus resist the bactericidal and opsonizing effects of normal human serum, in contrast to environmental isolates, which are highly serum susceptible. Immune responses to bacteremic V. vulnificus infections in human subjects have not been characterized. Serum from a patient who survived sepsis caused by V. vulnificus had substantial bactericidal and opsonizing immunoglobulin G (IgG) for his own bloodstream isolate. Killing was mediated by the classical complement pathway, whereas opsonization was effected by either the classical or the alternative pathway. IgG that reacted strongly with 55-, 58-, and 68-kilodalton outer membrane proteins was present in the patient's convalescent-phase serum but was absent from normal human serum. These findings suggest that humoral immunity to V. vulnificus, mediated by bactericidal and opsonizing antibody, emerges during infection and may be due, in part, to IgG directed against identifiable outer membrane proteins.

Peripheral vision and the aetiology of child pedestrian accidents

Three experiments examined whether age and sex differences in pedestrian accidents might be partly attributable to differences in the visual perception of peripheral stimuli. Primary schoolchildren and adults responded individually to the presentation of lights at retinal eccentricities of 2 degrees, 20 degrees and 40 degrees. Experiments 1 and 2 measured reaction times and Expt 3 measured subjects' expectations of foveal and peripheral events. There were no age or sex differences in expectations. Lights were detected fastest in the 20-40 degrees range. Movement times were not variable across eccentricities. As expected, adults' and 11-year-olds' detections were faster than eight- and six-year-olds'. A case is made for more problem-analytic and multi-theoretical research in the area of the child pedestrian accidents.

Delayed puberty

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Development of bactericidal antibody during Branhamella catarrhalis infection

The recent observation that Branhamella catarrhalis may cause a variety of infections in humans has stimulated interest in human host defenses against this organism. We encountered 21 patients with B. catarrhalis infection: seven with pneumonia, 13 with a purulent exacerbation of chronic bronchitis, and one with purulent sinusitis. Normal human serum (NHS) demonstrated no bactericidal activity against 20 of the 21 isolates. In contrast, 7 of 19 acute and 18 of 20 convalescent sera demonstrated significant bactericidal effects against the corresponding B. catarrhalis isolate. Heating convalescent sera to 56 C for 30 min abolished bactericidal activity. This activity was restored by NHS but not by complement-rich guinea pig serum. Selective blockage of the classic complement pathway eliminated bactericidal activity, whereas selective blockage of the alternative pathway did not. IgG isolated from convalescent serum plus NHS was bactericidal for the corresponding B. catarrhalis isolate. These results suggest that most patients with pulmonary infections due to B. catarrhalis develop a convalescent IgG antibody response that mediates serum bactericidal activity by the classic complement pathway.

Gonococcal endocarditis: a case series demonstrating modern presentation of an old disease

Gonococcal endocarditis appeared with striking frequency in the preantibiotic era compared with its surprising rarity today. We present a series of four episodes of gonococcal endocarditis, which presented to our institution in the last 2 years, after no cases in the previous decade. Three episodes involved the aortic valve and required emergency aortic valve replacement. One episode involved the tricuspid valve and was successfully cured with antibiotic infusion alone. Combining our four patients with the available 25 well-documented gonococcal endocarditis cases reported in the English medical literature during the antibiotic era, we demonstrated that the disease incidence may be increasing, that infections more often involve left-sided cardiac structures (particularly the aortic valve), and that the association with a quotidian fever curve, rash and arthritis, and overt gonococcal infection is less common than previously reported. These patients frequently present with fulminant and dramatic valvular insufficiency without immediately positive blood cultures and complete echocardiographic evaluation seems to provide a valuable aid in making a presumptive diagnosis of endocarditis and directing appropriate clinical management.

Lack of binding of serum glycoprotein hormone alpha subunit to concanavalin A-Sepharose reflects increased branching of the oligosaccharide chains

The lectin-binding properties of serum alpha subunit were studied by lectin affinity chromatography. Normal individuals and most patients with pituitary tumours produced alpha subunit which bound specifically to Concanavalin A-Sepharose (Con A). Some patients with pituitary tumours produced both Con A-reactive alpha subunit and alpha subunit which did not bind to Con A. Concanavalin A-Sepharose-binding alpha subunit from all sources bound strongly to Ricinus communis agglutinin-Sepharose after treatment with neuraminidase. Serum alpha subunit from those patients with pituitary tumours, which did not bind to Con A, bound to wheat germ agglutinin-Sepharose, exhibiting both weakly binding and strongly binding forms. Serum alpha subunit from both patients and controls, which did bind to Con A, showed only weak affinity for wheat germ agglutinin-Sepharose. Neither the low affinity nor the high affinity of serum alpha subunit from any source for wheat germ agglutinin-Sepharose was affected by neuraminidase. These findings show that (a) the predominant pattern of glycosylation of serum alpha subunit from normal controls is a Con A-reactive, biantennate complex oligosaccharide and (b) that the structural alteration which results in serum alpha subunit which does not bind to Con A in some patients with pituitary tumours is not an absence of carbohydrate, rather the alpha subunit contains highly branched, either complex or hybrid oligosaccharides.

Variation in the core and branch carbohydrate sequences of serum glycoprotein hormone alpha subunit as determined by lectin affinity chromatography

Serum alpha subunits from patients with pituitary tumours and from normal controls were studied for their ability to bind to Lens culinaris agglutinin-Sepharose (LCA), L-phytohaemagglutinin-agarose (L-PHA) and soybean agglutinin-Sepharose (SBA). Serum alpha subunits from normal controls which had previously been shown to bind to Concanavalin A-Sepharose (Con A) were not retained by LCA. In contrast, Con A-reactive alpha subunits from patients with pituitary tumours bound specifically to LCA. Non-Con A-reactive alpha subunits from patients with pituitary tumours were also largely not bound to LCA, but were retained by L-PHA. No alpha subunits from any source bound to SBA. These results indicate that the structural alterations resulting in non-Con A-reactive serum alpha subunits include highly branched complex oligosaccharides in addition to the hybrid-type glycans previously described. The increased branching appears to be associated with fucosylation in the core region of the oligosaccharides. Serum alpha subunit from any source appears to be devoid of terminal N-acetylgalactosamine residues. These structural modifications may be related to the variable biological activity of alpha subunit which has been reported.