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PubMed1985

The need to trace our roots in difficult times. The 1985 AANS presidential address.

Several important events that have played a major role in shaping the destiny of neurological surgery are recounted: the birth of neurosurgery; the founding of scientific surgery; the origin and evolution of microvascular technique in cerebrovascular surgery. In each case, the clinical breakthroughs stemmed from an apparently irrelevant basic laboratory investigation. Also, in each case, the transfer of the laboratory results to the bedside required clinicians who were prepared by training and knowledge to recognize the clinical significance of the fundamental observations. History tells us that if we are to sustain neurological surgery as a vibrant surgical specialty, we must continue to give top priority to the preparation of young minds through education and research. It is more important to understand this now than ever before, because never before have we been so preoccupied with social and economic issues: a preoccupation that is threatening to divert our attention from the main determinants of our specialty's future viability--the acquisition and application of new knowledge.

History, 19th Century↗
PubMed2006

Breakthrough curves and elution profiles of single solutes in case of adsorption isotherms with two inflection points.

The shape of breakthrough curves and elution profiles depends strongly on the course of the specific equilibrium functions characterizing the chromatographic system. For a highly efficient system the equilibrium theory provides a methodology how to predict the band profiles. The concept is frequently applied to analyze single component systems characterized by isotherms possessing simple shapes (Langmuir or anti-Langmuir behaviour). However, adsorption isotherms often possess more complicated shapes and have inflection points in their courses. This leads to the development of composite concentration waves and results in complex shapes of breakthrough curves and elution profiles. In this paper, the equilibrium theory is used to predict breakthrough curves for a chromatographic system characterized by an adsorption isotherm with two inflection points. The results obtained are validated by comparing with numerical solutions of the equilibrium dispersive model.

Adsorption↗
PubMed2002

Electroanatomic analysis of sinus impulse propagation in normal human atria.

INTRODUCTION: Better understanding of atrial propagation during sinus rhythm (SR) in normal hearts under the most normal physiologic conditions may be propaedeutic to pathophysiologic studies of complex atrial arrhythmias. In this study, qualitative and quantitative analyses of sinus impulse propagation in both atria were performed by electroanatomic mapping in patients with no organic heart disease who were undergoing an electrophysiologic procedure. METHODS AND RESULTS: Seven patients (5 men and 2 women; age 37 +/- 11 years) undergoing ablation of a left-sided accessory pathway were considered. Associated heart disease and coexisting atrial arrhythmias were excluded. After obtaining informed consent, electroanatomic mapping of both atria was performed during SR using a nonfluoroscopic system in the postablation phase. Mapping was accomplished in all patients with no complications. Qualitative analysis showed that sinus impulse propagation gives a reproducible activation pattern with minor individual variations. During interatrial propagation, two breakthroughs (anterior and posterior) in the left atrium are observed in the majority of cases. The anterior breakthrough, which reflects conduction over Bachmann's bundle, is predominant and shows a peculiar "preexcitation-like" endocardial activation pattern. Quantitative analysis showed minimal individual variations of propagation time intervals. Atria are activated simultaneously for 65% +/- 9% of the duration of the atrial systolic time interval. CONCLUSION: In normal humans, electroanatomic mapping of SR identifies a typical and reproducible propagation pattern during SR. Bachmann's bundle plays the most important role in interatrial propagation. Atria are activated simultaneously by sinus impulse for a relevant portion of the systolic time interval.

Adult↗
PubMed2000

Experience with live attenuated varicella vaccine (Oka strain) in healthy Japanese subjects; 10-year survey at pediatric clinic.

Live attenuated varicella vaccine (Oka strain, Biken Institute, Osaka, Japan) was administered to 973 healthy individuals over a 10-year period (1987-1997) at the pediatric clinic of Showa Hospital in Japan. We evaluated the relevant serological and clinical data, which were collected by questionnaire. Seroconversion by the immune adherence hemagglutination method was documented in 94% (805/860) of the initially seronegative subjects. Of the initially seropositive subjects, 56% (63/113) showed enhancement of antibody after vaccination. Reactions to the vaccine were generally insignificant, except for a rash at the injection site, seen in the first 3 days post-administration in 17% (41/241) of the recently vaccinated subjects. In March 1998, we conducted a survey of 559 of the initially seronegative subjects who had received the vaccine 0.6-10. 8 (mean 5.4) years earlier. Of these subjects, 21% (119/559) contracted breakthrough varicella. However, their symptoms were milder than those caused by natural varicella seen in unvaccinated children. Seroconversion was demonstrated in 92% (109/119) of these cases. The incidence of breakthrough disease decreased with a rise in postvaccination antibody titer to >==32. Four of the subjects (0.7% of 559) developed herpes zoster following vaccination, two of whom had earlier exhibited breakthrough varicella. Lesions in one case of zoster, without breakthrough varicella, appeared on the cervical dermatome at the injection site. The vaccine was safe and effective. However, there was a relatively high incidence of rash at the injection site with certain lot numbers used in recent years which warrants investigation.

Adolescent↗
PubMed1997

Clinical relevance of anti-interferon antibodies in the serum of chronic hepatitis C patients treated with interferon-alpha.

The development of anti-interferon (anti-IFN) antibodies in the serum of patients undergoing antiviral therapy has been postulated as one possible cause of interpatient variability in response to therapy. We analyzed the relationship between the appearance of anti-IFN antibodies and the loss of response to interferon-alpha (IFN-alpha), as characterized by a breakthrough of serum aminotransferase after a period of complete biochemical remission. The analysis involved clinical trials where neutralizing anti-IFN antibodies were detected by standardized and comparable methods. The results show that a time relationship between breakthrough and anti-IFN antibodies is observed in only a few cases and is independent of the type of IFN-alpha preparation used. Thus, causes of IFN resistance other than anti-IFN antibodies must also be implicated in most breakthrough cases. Another potential is the selection of drug-resistant viral strains. Current ration behavior following the appearance of breakthrough (from whatever cause) in clinical practice advocates changing treatment to a different type of IFN-alpha. The detection of anti-IFN enzyme-linked immunosorbent assay (ELISA) antibodies or IFN neutralizing antibodies does not appear to provide any additional information for decision making.

Alanine Transaminase↗
PubMed1983

'Breakthrough' enterococcal septicemia in surgical patients. 19 cases and a review of the literature.

We studied 19 surgical patients with 24 postoperative episodes of enterococcal septicemia not arising from the biliary or urinary tracts or from infected heart valves. Fifteen episodes occurred despite the administration of broad-spectrum antibiotics; in only one patient were these drugs effective against enterococcus. There were 14 episodes of enterococcemia in 11 patients following which the patient survived for at least one week. Thirteen (93%) of those episodes were treated with either ampicillin or drainage, or both. Five of the six long-term survivors received ampicillin therapy. Overall mortality was 68%. The data suggest that the enterococcus may emerge as a blood-borne pathogen in immunodepressed, postoperative patients receiving antibiotics for other infections of enteric origin. Antibiotic therapy specifically directed against this organism (and surgical drainage, if necessary) may be indicated during polymicrobial sepsis of enteric or mixed origin. If the spectrum of antibiotics does not include enterococcus, this organism can cause "breakthrough" sepsis, as can many other opportunistic organisms.

Adolescent↗
PubMed2002

Social actors and discourse on abortion in the Mexican press: the Paulina case.

The "Paulina case" is the story of a 13-year-old girl in Mexico who became pregnant in 1999 after being raped. Although she received permission to obtain a legal abortion, the hospital convinced her mother through misleading information to decline the abortion. This case has become an almost obligatory point of reference when abortion is discussed in Mexico. This paper analyses how the Mexican press portrayed the Paulina case and the social actors who participated in it--Paulina herself, Paulina's allies, the state government, the Catholic Church, members of the political party PAN and the National Human Rights Commission. One of the great breakthroughs of this case was that the denial of an abortion was judged to be a form of negligence. In demanding justice for Paulina, Paulina's allies were given moral authority in the press to denounce those who denied her an abortion. While the government of Baja California state and members of the PAN were held responsible for their role in the case, the Catholic Church, who was also responsible, seemed to escape criticism. It is probable that the large emotional weight of the Paulina case accomplished more in terms of changing public opinion in support of women's right to decide on abortion than any other single event to date.

Abortion, Legal↗
PubMed1991

Electrocardiographic body surface potential mapping in the Wolff-Parkinson-White syndrome. Noninvasive determination of the ventricular insertion sites of accessory atrioventricular connections.

BACKGROUND: A reliable, noninvasive procedure to determine the location of accessory atrioventricular connections in patients with Wolff-Parkinson-White syndrome would add an important diagnostic tool to the clinical armamentarium. METHODS AND RESULTS: Body surface potential mapping (BSPM) using 180 electrodes in various-sized vests and displayed as a calibrated color map was used to determine the ventricular insertion site of the accessory atrioventricular (AV) connections in 34 patients with Wolff-Parkinson-White syndrome. Attempts were made to determine the 17 ventricular insertion sites described by Guiraudon et al. All 34 patients had an electrophysiologic study (EPS) at cardiac catheterization, and 18 had surgery so the ventricular insertion sites could be accurately located using EPS at surgery. A number of physiologic observations were also made with BSPM. CONCLUSIONS: The following conclusions were drawn: 1) BSPM using QRS analysis accurately predicts the ventricular insertion site of accessory AV connections in the presence of a delta wave in the electrocardiogram; 2) the ventricular insertion sites of accessory AV connections determined by BSPM and by EPS at surgery were identical or within one mapping site (1.5 cm or less) in all but four of 18 cases; three of the four exceptions had more than one accessory AV connection, and the other had a very broad ventricular insertion; 3) BSPM and EPS locations of the accessory AV connections correlated very well in the 34 cases despite the fact that BSPM determines the ventricular insertion site and EPS determines the atrial insertion site of the accessory AV connection; 4) as suggested by the three cases of multiple accessory AV connections, EPS and BSPM may be complementary since BSPM identified one pathway and EPS identified the other (in the case with a broad ventricular insertion, BSPM and EPS demonstrated different proportions of that insertion); 5) BSPM using ST-T analysis is very much less accurate in predicting the ventricular insertion site of accessory AV connections unless there is marked preexcitation; 6) standard electrocardiography using the Gallagher grid methodology (but with no attempt at stimulating maximal preexcitation) was not as accurate as QRS analysis of BSPM in predicting the ventricular insertion site of the accessory AV connection; however, exact comparison is hampered by the different number and size of the Gallagher and Guiraudon insertion sites; 7) BSPM using QRS analysis appears to be very accurate in predicting right ventricular versus left ventricular posteroseptal accessory AV connections; 8) typical epicardial right ventricular breakthrough, indicative of conduction via the specialized AV conduction system, occurs in all patients with left ventricular free wall accessory AV connections; 9) epicardial right ventricular breakthrough was not observed in cases with right ventricular free wall or anteroseptal accessory AV connections; 10) epicardial right ventricular breakthrough can occur in the presence of posteroseptal accessory AV connections, whether right or left ventricular; and 11) the delay in epicardial right ventricular breakthrough in cases with left ventricular insertion may provide a marker to estimate the degree of ventricular preexcitation.

Adult↗
PubMed2006

Orthoptic indications for contact lens wear.

Orthoptic anomalies are prevalent: they are encountered in at least 5% of patients seen in a typical primary eyecare practice. Several cases are reviewed that highlight the role of contact lenses in treating orthoptic anomalies. In particular, contact lenses are the preferred optical approach to the correction of anisometropia, and it is often argued that anisometropia should be corrected as young as possible. However, fitting contact lenses to patients, particularly children, with anisometropic amblyopia has been problematic because there is no immediate binocular acuity improvement when the contact lenses are inserted which reduces patient motivation. Continuous wear with silicone hydrogels represents a breakthrough for these cases and some illustrative case studies are given. The visual deficit in amblyopia can be reduced in some cases solely by fitting contact lenses, without the need for occlusion therapy. Other orthoptic uses of contact lenses are reviewed including: correcting motor deviations, occlusion, and infantile onset nystagmus. It is concluded that there are orthoptic anomalies where contact lenses are the preferred mode of correction. It is in patients' best interest for practitioners to discuss contact lenses in these cases.

Amblyopia↗
PubMed2004

[From "wet caries" to controllable complication. History of post-traumatic and postoperative osteitis].

In former times treatment of osteomyelitis was based on very few surgical principles such as incision of the infected region, debridement with sequestrectomy, and continuous drainage to prevent superficial closing of the wound. There were no rules for asepsis, anesthesia, and microbiology in the treatment of bone infection. Therapy improved dramatically when J. Lister introduced and performed antisepsis. With the beginning of the twentieth century it became much more standardized and differentiated. In the 4th decade of the twentieth century, the development of antibiotics changed the regime of osteomyelitis therapy again. Especially systemic intravenous antibiotic therapy was very successful in the treatment of the hematogeneous osteomyelitis. Treatment failed in post-traumatic and postoperative osteitis. Local antibiotic therapy on a delivery system was the breakthrough for these cases. The application of PMMA cement as an antibiotic delivery system led to this new possibility for treating bone infections and is still in use nowadays.

Anti-Bacterial Agents↗
PubMed1996

Anatomically based ablation of atrial flutter in an acute canine model of the modified Fontan operation.

BACKGROUND: Lateral tunnel total cavopulmonary connection, also called the modified Fontan operation, uses a baffle through the right atrium. We established, in an acute canine model, that atrial flutter after total cavopulmonary connection revolves around a line of conduction block imposed by the free wall lateral tunnel suture line. We hypothesized that a line of conduction block between the free wall total cavopulmonary connection suture line and the tricuspid anulus would interrupt atrial flutter in this model. OBJECTIVE: Our objective was to determine whether a cryolesion placed between the free wall total cavopulmonary connection suture line and the tricuspid anulus would terminate atrial flutter in an acute canine model. METHODS: Seven adult dogs underwent median sternotomy and institution of cardiopulmonary bypass. A suture line was placed through a right atriotomy to simulate total cavopulmonary connection lateral tunnel construction. Form-fitting 253-point biatrial endocardial mapping electrodes were placed via bilateral ventriculotomies. Atrial flutter was induced by atrial burst pacing. A cryothermal lesion was then placed between the free wall total cavopulmonary connection suture line and the tricuspid anulus in the low lateral right atrium (i.e., CRYO 1 procedure), and reinduction of atrial flutter was attempted. If atrial flutter was reinduced, the cryolesion was modified superiorly to include the caudal portion of the atriotomy (i.e., CRYO 2 procedure). Activation sequence maps were generated for sinus rhythms before and after the cryolesions were placed and for induced arrhythmias. RESULTS: In all seven cases, atrial flutter was inducible after suture line placement, before placement of a cryolesion. The reentrant circuit incorporated both caval orifices in five of seven cases and was successfully ablated by the CRYO 1 approach in each case. Atrial flutter was not inducible after placement of the CRYO 2 lesion in the remaining two cases, in which breakthrough of the wave front occurred across the lateral tunnel suture line in the intercaval region. Activation sequence maps of sinus rhythm after placement of the cryolesions demonstrated a conduction block at the site of the lesion. CONCLUSIONS: A linear cryothermal lesion placed between the free wall aspect of the total cavopulmonary connection suture line and the tricuspid anulus created a line of conduction block that successfully ablates atrial flutter in the canine model.

Acute Disease↗
PubMed1997

Mammalian telomerase: catalytic subunit and knockout mice.

For the second time this year random cDNA sequencing, in combination with data from unicellular eukaryotes, has made a significant contribution to the analysis of human telomerase. Two groups have reported mammalian homologues of the Tetrahymena p80 telomerase-associated protein, in both cases the key breakthrough being mammalian cDNA clones with database matches to Tetrahymena p80. This has now been joined by the sequence of a candidate for the human telomerase catalytic subunit. The discovery that its message abundance closely follows telomerase activity could make a major impact on the utility of telomerase as a diagnostic marker for human malignancy. In addition, Blasco et al . report the phenotype of a transgenic mouse deleted for the mTR gene, which encodes the essential RNA component of telomerase. Interestingly tumour formation is unaffected in these mice, strengthening the argument that telomerase expression in mouse tumourigenesis is an innocent bystander rather than a necessary event. However, fundamental differences between the genomic organisation of mouse and human telomeres mean that the mouse is not a straightforward model to critically test the role of telomere loss and telomerase in human malignancy.

Amino Acid Sequence↗
PubMed2001

What factors are related to impairment of cerebrovascular reserve before and after arteriovenous malformation resection? A cerebral blood flow study using xenon-enhanced computed tomography.

OBJECTIVE: To examine the incidence and possible determinants of impaired vascular reserve in arteriovenous malformation (AVM)-affected brain, before and after surgery. METHODS: In a prospective study of 30 patients, the regional cerebrovascular reserve capacity (rCRC) and the vasodilated regional cerebral blood flow (rCBF) were assessed during an acetazolamide challenge, using xenon-enhanced computed tomography, before and after complete AVM resection. Single brain slices at the level of the basal ganglia were examined, and scanning through the AVMs was avoided. Five regions of interest in the AVM-bearing hemisphere were compared with their counterparts in the unaffected hemisphere. Vasodilated rCBF reductions of at least 20% in one or more regions of interest and rCRC values of less than 10 ml/100 g/min were considered to be significant. RESULTS: Ipsilateral vasodilated rCBF was significantly reduced in 17 patients before surgery and 15 patients after surgery. Ipsilateral rCRC was impaired in 14 patients before surgery and 12 patients after surgery. Large AVM size, venous congestion, and AVM-related vascular territories were correlated with impaired vascular reserve in AVM-nonadjacent brain tissue before surgery. Similar correlations were observed after surgery, except that not AVM size but a large number of AVM-supplying vascular territories was correlated. Moreover, the smallest AVMs and those supplied by a single vascular territory, as well as hemorrhage and nonhemorrhagic neurological deficits as presenting symptoms, were correlated with reduced ipsilateral vasodilated rCBF before surgery. Among patients with AVMs and nonhemorrhagic epilepsy, a trend of impaired cerebrovascular reserve was observed. In the only case of postresectional "breakthrough," the preoperative rCRC was not impaired but abnormally high. CONCLUSION: Among the determinants of impaired cerebrovascular reserve, AVM size is already a constituent of current grading scales and decision-making paradigms, whereas factors such as venous congestion have been less closely considered or less obvious but may deserve increased attention in the future. Nonhemorrhagic epilepsy in patients with AVMs may constitute the clinical equivalent of chronic cerebral ischemia in a murine model. Postresectional breakthrough may be partly attributable to individual predisposition to excessive vasoreactivity in the whole brain.

Acetazolamide↗
PubMed2006

[Update on chickenpox].

Primary infection by varicella-zoster virus causes chickenpox and herpes zoster. At 14 years of age, 91% of the population have already suffered the illness and after 30 years, more than 95% have done so. In 1999, the hospitalization rate was 2.4 per 1,000 chickenpox cases in those under 14 and 15.5 per 1,000 cases in those over 14. A total of 73% of deaths recorded during the period 1991-2000 were in the older than 14 year old group. Efficacy of varicella vaccine after a 7-8 years period is 87%; a milder case of chickenpox (breakthrough) can appear in vaccinated people 42 days after vaccination. The introduction of the vaccine may be proposed to stop or decrease virus circulation among the population or to decrease complications and mortality from chickenpox. According to the objective proposed, different strategies that imply risks and benefits should be conducted.

Adolescent↗
PubMedDate not supplied

Treatment of febrile neutropenia with cefepime monotherapy.

BACKGROUND AND OBJECTIVE: The empirical administration of a broad-spectrum beta-lactam antibiotic, either as monotherapy or in combination with an aminoglycoside, is an essential component of the initial management of patients with fever and severe neutropenia. Multiple antibiotics have been tested for this indication. Cefepime is a fourth-generation cephalosporin with in vitro activity against most gram-negative and many gram-positive bacteria. We have studied the use of this agent as monotherapy in this indication. METHODS: One hundred and twenty-six episodes of febrile neutropenia in 98 adults with hematological malignancies were treated with cefepime monotherapy. Cefepime was given at a dose of 2 g every 8 h i.v. Most episodes (49%) were fever of unexplained origin, while a microbiologically documented and clinically documented infection occurred in 25% episodes each. Seventy-six (61%) episodes occurred after conventional chemotherapy, while 51 (41%) after a hematopoietic stem cell transplantation. RESULTS: Twelve episodes (10%) were not evaluable for response. Among the 114 evaluable episodes, 69 (55% of the initial sample and 61% of those evaluable) responded to cefepime monotherapy, while therapy failed in 45 cases (36% of the initial sample and 39% of those evaluable), including 14 cases who developed breakthrough bacteremia during therapy. There were no deaths due to bacterial infection. At the end of all antibiotic therapy (final outcome) 69 episodes were cured only with monotherapy, 47 were cured with modification of therapy and 10 patients died from an unrelated cause. The only variable that appeared to correlate with response to therapy was the duration of neutropenia, which was longer among patients who failed or developed breakthrough bacteremia than among those who responded to monotherapy. INTERPRETATION AND CONCLUSIONS: Initial empirical antibiotic therapy with cefepime as a single agent in patients with febrile neutropenia and a hematological malignancy is effective, but patients with prolonged neutropenia appear to be at higher risk for failure. However, with appropriate therapeutic changes the risk of dying from a bacterial infection is very low.

Adolescent↗
PubMed1991

Epicardial activation and repolarization patterns in patients with right ventricular hypertrophy.

To map global epicardial repolarization patterns and test the "SI" model of T wave generation, the patterns of epicardial activation and repolarization in patients with chronic pulmonary thromboembolism and right ventricular hypertrophy were studied by computerized mapping techniques and monophasic action potential (MAP) recording. The ventricular activation patterns were characterized by delayed right ventricular activation and the absence of normal early epicardial ventricular breakthrough in some cases. The repolarization patterns were characterized by nonuniform distribution of T wave morphologies. The T waves were predominantly positive over the left ventricular epicardium and negative or biphasic over the right ventricular epicardium. The activation-recovery (A-R) intervals were measured from the local activation to the maximal dV/dt of the upstroke of the T waves (Wyatt method). The difference between the A-R intervals and the MAP from onset of activation to 90% repolarization (MAP90) varies according to T wave morphology and could be as high as 96 msec with positive T waves, despite significant correlations (r = 0.56-0.90) between MAP90 and A-R intervals for each morphology. Better overall correlations were found if the minimal dV/dt on the downslope of the positive T waves was chosen to estimate the time of local repolarization (alternative method). Using this method, the mean A-R intervals were the same over the right and left ventricles. Cardiopulmonary bypass significantly prolonged the action potential duration equally at all parts of the epicardium. We conclude that in patients with right ventricular hypertrophy, the time of local repolarization can be estimated by our alternative method; the right ventricle completes activation and repolarization later than the left ventricle, and the distribution of T wave morphologies is nonuniform, with predominantly positive T waves observed over the left ventricle and negative or biphasic T waves observed over the right ventricle. These findings are compatible with the SI model of the generation of T waves.

Action Potentials↗
PubMed1976

Management of endometriosis with oral medroxyprogesterone acetate.

Efficacy of oral medroxyprogesterone acetate (MPA) was assessed in 35 women with an established diagnosis of endometriosis (33 pelvic and 2 abdominal). MPA was given in a dosage of 30 mg daily for 90 days. Results indicated improvement or remission in all cases, even though breakthrough bleeding occurred in 8. Twenty-six were treated for associated infertility. Twelve of these became pregnant following treatment. Pregnancy rate in those women whose husbands were fertile was 90%. Side effects included spotting and breakthrough bleeding. The patients usually remained amenorrheic and anovulatory while receiving MPA. Posttreatment resumption of ovulation was prompt. The findings indicate that oral MPA is a useful therapeutic agent in the management of minimal to moderate endometriosis, particularly when it is associated with infertility.

Abdominal Neoplasms↗