The Brain Bench: virtual tools for stereotactic frame neurosurgery

We present a suite of neurosurgery supporting tools developed around (i) the Virtual Workbench, a productive environment for the control of 3-D data, in which delicate work can be performed for hours on end without strain, and (ii) the Electronic Brain Atlas, integrating the major print brain atlases in day-to-day clinical use. We describe in detail the Brain Bench, a surgical planning system for stereotactic frame neurosurgery. Its objective is to prepare faster plans; have a better and more accurate choice of target points; improve the avoidance of sensitive structures; have fewer sub-optimal frame attachments and speedier, more effective planning and training. If validated by a clinical study now under way, this will improve medical efficacy and reduce costs.

Designing virtual selectors for surgeons

Virtual Reality (VR) applications involve the use of manipulators or 'virtual tools' such as pointers, grippers and containers. Manipulation of such tools is a key feature of VR applications. Less attention has been directed towards designing the ways in which users select particular options or information, as they interact in the virtual world, by means of selectors. This is particularly important in the case of professional users, such as surgeons, who typically make heavy use of both selection and manipulation, switching frequently between the two in the course of their work. In this paper we describe the design and evaluation of two types of selector tool for use in medical VR applications. In this account, we provide details of the background behind the research and focus on design aspects of selector tools for use in a particular task context, that of medical surgery planning.

Diagnosis of sibling species of Drosophila involved in the colonization of North America by D. subobscura

To determine the effects of the recent colonization of the west coast of North America by the Palaearctic species Drosophila subobscura on the dynamics of the Drosophila populations, the sibling species D. athabasca and D. azteca must be classified unambiguously. We have characterized these two species using three molecular techniques: allozymes, mtDNA and RAPDs. All three techniques allow the classification of any individual as belonging to either species. The study of five localities in northern California and southern Oregon show that the area of overlap is larger than previously described.

Hemodynamic effects of plasma exchange in septic patients: preliminary report

To assess the effects of plasma exchange on the hemodynamic performance of septic patients, we studied 12 septic patients (11 males and 1 female, age range 19-64, mean 39 +/- 17 years). After cardiovascular stabilization, plasma exchange was performed in the spontaneous mode via a femorofemoral arteriovenous shunt; during the treatment the infusion rate of cardiovascular drugs and the mechanical ventilation setting were not modified. Heart rate, pulmonary artery occlusion pressure, and peripheral vascular resistance did not change significantly. The stroke volume index increased significantly (from 49 +/- 9 to 60 +/- 9 ml/min/m2; p < 0.05) as well as the cardiac index (from 5.5 +/- 1.2 to 6.3 +/- 0.8 liters/min/m2, the oxygen delivery (from 785 +/- 166 to 872 +/- 118 ml/min/m2; p < 0.05), and the left ventricular stroke work index/pulmonary artery occlusion pressure ratio (from 4.03 +/- 1.92 to 5.07 +/- 2.54; p < 0.05). The oxygen consumption did not change. Four patients survived. In conclusion, in our patients plasma exchange was associated with an improvement in cardiac function, possibly due to the elimination of some sepsis mediator(s) with negative inotropic properties.

Analysis of inbreeding in a colonizing population of Drosophila subobscura

An analysis of the effects of inbreeding on the genetic structure of a colonizing population of Drosophila subobscura has been carried out. Species of Drosophila, particularly D. subobscura, may have lethal alleles associated with chromosomal inversions and our aim was to assess the extent to which the genome is balanced in this way. The frequencies of chromosomal inversions were compared between a large population and a set of 72 lines that were maintained by brother-sister mating for 10 generations. Fisher's matrix method was used to calculate the expected homozygosity in these inbred lines for 5 allozyme loci (Aph, Hk-1, Lap, Odh, and Pept-1) used as markers of large chromosomal segments. Furthermore, the expected rates of fixation corresponding to these allozyme loci were also calculated. The results show that the amount of homozygosis observed did not differ significantly from expectations (with the corresponding loss of lines as a consequence of the reduction in viability). However, two deviations from strict neutrality were observed: there was a heterozygote excess at the Lap locus, and the frequency of the O5 inversion (always associated with a lethal gene in colonizing populations) was higher than expected.

Sino-atrial and atrio-ventricular node dysfunction in a case of tizanidine overdose

We report the occurrence of sino-atrial and a-v node dysfunction in a case of tizanidine overdose. Possible pathphysiological mechanism of arrhythmias and its clinical significance are presented.

Colonization of the Americas by Drosophila subobscura: lethal-gene allelism and association with chromosomal arrangements

Drosophila subobscura is a Palearctic species that has recently colonized the Americas. It was first found in 1978 in Puerto Montt, Chile, and in 1982 in Port Townsend, WA. The colonization and rapid expansion of the species in western South and North America provides distinctive opportunities for investigating the process of evolution in action. The inversion polymorphism in the O chromosome from populations of central California and northern Washington, separated by 1300 km, corresponds to a previously observed latitudinal cline, also observed in Europe. Recessive lethal genes are not randomly distributed among the chromosomal arrangements. The incidence of lethal allelism is high, yielding unrealistically low estimates of the effective size of these populations (on the order of 1000 individuals). The high incidence of lethal allelism is likely to be a consequence of the low number of the American colonizers (on the order of 10-100 individuals), but the persistence of the allelism over several years suggests that some lethal-carrying chromosomes may be heterotic owing to shared associations between lethal and other genes.

Biosynthesis of C3 by human mesangial cells. Modulation by proinflammatory cytokines

Deposits of complement (C) components are found in the glomeruli of patients with various glomerulonephritides without detectable immunoglobulins, thus suggesting a pathogenetic role of the locally produced proteins of this system. In the present study, we have examined human mesangial cells (HMC) for their ability to secrete C3. Three different cell lines were examined and all showed a basal production of C3, which was up-regulated following stimulation with IL-1 beta. IL-6 had no direct stimulatory effect on its own, but synergized with IL-1 to induce an increased production of C3 in the culture supernatant and its relative amount was confirmed by SDS-PAGE and immunoblot. Another agonist such as lipopolysaccharide was not able to induce any significant C3 synthesis. Analysis of C3 HMC gene expression, performed by both reverse transcription-polymerase chain reaction of isolated RNA and Northern blot, confirmed the parallel increase of the specific transcript under IL-1 beta and IL-1 beta + IL-6 stimulation. From these data we conclude that production of C3 in the mesangium could have a pathophysiologic relevance.

Colonization of America by Drosophila subobscura: the founder event and a rapid expansion

The recent colonization of the American continent by Drosophila subobscura offers a unique opportunity to analyze the response of different genomic entities to a new environment. Here, results from a study of 15 allozyme loci in six North American and seven South American populations are compared with existing data from Palearctic populations. In general, only alleles with a frequency higher than 0.1 in European populations are present in America. The observed alteration in allele frequencies can be explained by a founder event. Although some significant latitudinal clines for allozyme frequencies have been detected, the results obtained are not as clear-cut as are those for chromosomal inversions. Overall heterozygosity is similar between North and South American populations and does not differ from that of Palearctic populations. This observation experimentally corroborates the results provided by theoretical models in which the average heterozygosity per locus depends not only on the size of bottleneck but also on the rate of population growth. The resemblance between North and South American populations is clearly manifested by a geometrical representation using Bhattacharyya's distance and a multidimensional scaling technique. Furthermore, these American populations are clearly differentiated from the Palearctic populations.

Primary systemic amyloidosis with giant hepatomegaly and portal hypertension: a case report and a review of the literature

Amyloidosis is a manifestation of a group of diseases resulting from the variable infiltration of multiple organs by a fibrillar protein called amyloid. Hepatic involvement in amyloidosis is common both in the primary and in the secondary forms, whereas clinically-dominant liver amyloidosis is relatively rare. The authors describe a case of primary systemic amyloidosis with giant hepatomegaly, portal hypertension and renal insufficiency; the patient did not develop jaundice, ascites or gastrointestinal bleeding but died 6 months later, death being due to cerebral haemorrhage.

Dietary factors and gastric cancer risk. A case-control study in Spain

BACKGROUND

Evidence supports that gastric cancer has an environmental etiology, of which diet appears to be the most important component. The authors examined the effect of diet on the risk of gastric cancer.

METHODS

A case-control study of dietary factors and gastric cancer was conducted between September 1986 and March 1989 in the Barcelona metropolitan area, Spain. One hundred seventeen cases with histologically confirmed diagnosis of gastric adenocarcinoma were matched by age, gender, and whether they possessed a telephone to 234 community controls. One hundred eighty-eight (80.3%) controls were selected by random-digit telephone dialing and 46 (19.7%) by neighborhood of residence. Information about frequency and amount of consumption of 89 food items in one year was gathered by using a questionnaire, and cases and controls were interviewed in their homes by trained interviewers. Unconditional logistic regression was used for the analysis.

RESULTS

Gastric cancer risk rose with increasing intake of smoked and pickled foods (OR 3.67 for upper tertile) and salt (OR 2.11 for upper quartile). Intake of citrus fruits (OR 0.47 for upper tertile) and raw-green vegetables (OR 0.56 for upper quartile) appeared to be protective. Gastric cancer risk was not associated with intake of cereals, rice, total vegetables, and fruits as a whole.

CONCLUSIONS

These data suggest that high intake of salt and smoked and pickled food may be associated with a high risk of gastric cancer, and this association could be due to intragastric formation of nitrosamines. The negative association with citric and green vegetables consumption to be associated with the inhibition of nitrosation process.

Dietary factors and gastric cancer risk. A case-control study in Spain

BACKGROUND

Evidence supports that gastric cancer has an environmental etiology, of which diet appears to be the most important component. The authors examined the effect of diet on the risk of gastric cancer.

METHODS

A case-control study of dietary factors and gastric cancer was conducted between September 1986 and March 1989 in the Barcelona metropolitan area, Spain. One hundred seventeen cases with histologically confirmed diagnosis of gastric adenocarcinoma were matched by age, gender, and whether they possessed a telephone to 234 community controls. One hundred eighty-eight (80.3%) controls were selected by random-digit telephone dialing and 46 (19.7%) by neighborhood of residence. Information about frequency and amount of consumption of 89 food items in one year was gathered by using a questionnaire, and cases and controls were interviewed in their homes by trained interviewers. Unconditional logistic regression was used for the analysis.

RESULTS

Gastric cancer risk rose with increasing intake of smoked and pickled foods (OR 3.67 for upper tertile) and salt (OR 2.11 for upper quartile). Intake of citrus fruits (OR 0.47 for upper tertile) and raw-green vegetables (OR 0.56 for upper quartile) appeared to be protective. Gastric cancer risk was not associated with intake of cereals, rice, total vegetables, and fruits as a whole.

CONCLUSIONS

These data suggest that high intake of salt and smoked and pickled food may be associated with a high risk of gastric cancer, and this association could be due to intragastric formation of nitrosamines. The negative association with citric and green vegetables consumption to be associated with the inhibition of nitrosation process.

Cerebellar vermis hypoplasia in a case of cri-du-chat syndrome

We describe a 6-year-old child who presented the phenotype of cri-du-chat disease. The study of her caryotype confirmed an interstitial deletion of the short arm of chromosome 5. The neurological examination showed mental retardation, behavioral disturbances and features of cerebellar and cortico-spinal impairment. The MRI scan of the brain showed hypoplasia of the vermis associated with dysgenesia of the corpus callosum. This is the first report of vermian hypoplasia in cri-du-chat disease. We suggest that the most likely pathogenesis of this malformation is a midline dysraphia.

Generalized juvenile polyposis with mixed pattern and gastric cancer

Generalized gastrointestinal juvenile polyposis is a rare form of diffuse polyposis in which cancer infrequently develops. A clinical case is described in which gastric polyps showed a variety of histological features, including both in situ and invasive adenocarcinoma. Many mixed lesions were observed, confirming a morphological sequence already documented in colorectal tumorigenesis but still undefined in gastric tumors. The patient seems strongly predisposed to gastric cancer, presumably on a genetic basis, because he developed a malignancy in a hyperplastic juvenile polyp, usually not considered a precancerous lesion. There is no doubt that cases like this may be important for accurate genetic evaluation and biological characterization.

Dietary factors and gastric cancer risk. A case-control study in Spain

BACKGROUND

Evidence supports that gastric cancer has an environmental etiology, of which diet appears to be the most important component. The authors examined the effect of diet on the risk of gastric cancer.

METHODS

A case-control study of dietary factors and gastric cancer was conducted between September 1986 and March 1989 in the Barcelona metropolitan area, Spain. One hundred seventeen cases with histologically confirmed diagnosis of gastric adenocarcinoma were matched by age, gender, and whether they possessed a telephone to 234 community controls. One hundred eighty-eight (80.3%) controls were selected by random-digit telephone dialing and 46 (19.7%) by neighborhood of residence. Information about frequency and amount of consumption of 89 food items in one year was gathered by using a questionnaire, and cases and controls were interviewed in their homes by trained interviewers. Unconditional logistic regression was used for the analysis.

RESULTS

Gastric cancer risk rose with increasing intake of smoked and pickled foods (OR 3.67 for upper tertile) and salt (OR 2.11 for upper quartile). Intake of citrus fruits (OR 0.47 for upper tertile) and raw-green vegetables (OR 0.56 for upper quartile) appeared to be protective. Gastric cancer risk was not associated with intake of cereals, rice, total vegetables, and fruits as a whole.

CONCLUSIONS

These data suggest that high intake of salt and smoked and pickled food may be associated with a high risk of gastric cancer, and this association could be due to intragastric formation of nitrosamines. The negative association with citric and green vegetables consumption to be associated with the inhibition of nitrosation process.

Primary malignant non-Hodgkin's lymphoma of the lung arising in mucosa-associated lymphoid tissue (MALT)

We describe a 10 yr follow-up of a patient with a primary malignant non-Hodgkin's lymphoma of the lung, arising in mucosa-associated lymphoid tissue (MALT). Although the patient was not treated with chemotherapy or radiotherapy, no peripheral spread occurred, confirming that MALT-associated lymphomas apparently remain localized until late in the course of the disease.

Primary malignant non-Hodgkin's lymphoma of the lung arising in mucosa-associated lymphoid tissue (MALT)

We describe a 10 yr follow-up of a patient with a primary malignant non-Hodgkin's lymphoma of the lung, arising in mucosa-associated lymphoid tissue (MALT). Although the patient was not treated with chemotherapy or radiotherapy, no peripheral spread occurred, confirming that MALT-associated lymphomas apparently remain localized until late in the course of the disease.

[Retrospective evaluation of the effectiveness of the BCG vaccine campaign in newborns of Barcelona]

BACKGROUND

The aim of this study was to know the efficacy of the BCG vaccination campaign of the newborns of Barcelona carried out during the period from 1966-1974.

METHODS

To achieve this aim an epidemiologic investigation was undertaken by an observational analytical study of paired cases and controls. Two hundred and fifty randomly selected cases were studied between 1978-1988 from between 4-21 years of age during the study period. The cases were paired with 750 controls (1:3) with identical conditions and age, sex and place of residence. Statistical analysis of data was performed by the specific methods for this type of study.

RESULTS

The estimated gross odds ratio was 0.68; the interval of confidence 95% and 0.51-0.91 (p < 0.025). The efficacy of this vaccination campaign was estimated as weak at 32%, in the age group and investigation time being greater in males and diminished with time. The percentage of new cases of tuberculosis potentially prevented by this campaign was calculated at 13%.

CONCLUSIONS

The weak efficacy of the BCG vaccination campaign may be attributed not only to the unforeseen effects of this vaccine but also to the deficient operative aspects of the campaign itself.

[Epidemiology of obesity among the adult population of Catalonia]

Several epidemiological studies have shown that obesity is related to the mortality from cardiovascular disease. In this study, the epidemiology of obesity and the correlation between body mass index and other cardiovascular risk factors was studied in a representative sample of the adult population of Catalonia. It was obtained a random sample (n = 704) of the adult population of Catalonia aged 15 or more years. Height and weight were measured and body mass index (BMI) was calculated (height in Kg/weight2 in m2). Obesity was defined as a BMI greater than 30, and overweight as a BMI from 25 to 30. In the first 314 participants, it was determined the concentration of total cholesterol, cholesterol-HDL and triglyceride, and it was measured the blood pressure. The correlation between BMI and other cardiovascular risk factors was analysed. The study was carried out in 1989. The mean of BMI increased with age in both sexes. BMI was significantly higher in men (26 kg/m2) than women (25 kg/m2). The prevalence of obesity was of 12% in both men and women, and the prevalence of overweight was of 48.5% in men and 38% in women. The prevalence of arterial hypertension, hypercholesterolemia and diabetes was greater individuals with obesity, with differences statistically significant for hypertension (odds ratio of 3.26). The multiple logistic regression analysis showed that the association between obesity and hypertension was not statistically significant (OR adj. = 2.09), when the effect of the other risk factors, the age and sex were controlled.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute hepatitis induced by cyclofenil: a case report

The case of a 47-year old woman suffering from acute hepatitis caused by cyclofenil, a drug proposed for the treatment of anovulation and scleroderma, is presented. Hepatitis developed seven weeks after the beginning of administration of the drug and its course was reversible after withdrawal. The case is documented on the basis of liver histology and the exclusion of other causes of acute hepatitis.

Effect of aspirin and indomethacin on epidermal growth factor secretion in duodenal tissue fragments cultivated in vitro

The aim of the present study was to determine the effect of aspirin and indomethacin on epidermal growth factor (EGF) secretion in duodenal tissue fragments cultivated in vitro. The fragments were obtained from healthy subjects by gastroscopy, cultured in McCoy's medium and gassed with 95% O2 and 5% CO2 at 37 degrees C. After an incubation of 30 min, the culture medium was decanted, and the quantity of hormone determined by radioimmunoassay. The mean EGF level detected in the medium was 10.94 ng/mg protein tissue. The addition of aspirin (final concentration 10(-7) M) to the medium reduced mean EGF levels to 7.5 ng/mg (p less than 0.05), whereas aspirin 10(-8) M did not produce such a modification. The addition of indomethacin (final concentration 10(-8) M) decreased mean EGF levels to 5.37 ng/mg (p less than 0.001). In all experimental conditions, the addition of anti-somatostatin (SRIF) antibodies determined a remarkable increase in EGF (p less than 0.01). The results of this study show aspirin and indomethacin to be direct, not SRIF-mediated inhibitors of EGF release.

The role of epidermal growth factor in the pathogenesis of peptic ulcer disease

Duodenal biopsies obtained from seven normal subjects and six ulcerous patients were cultured in vitro for 30 min at 37 degrees C under various experimental conditions. Epidermal growth factor (EGF) and somatostatin released in the culture medium were determined by radioimmunoassay. Under basal conditions, EGF and somatostatin levels were significantly higher in normal subjects (11.49 +/- 3.07 ng/mg protein and 3.06 +/- 0.8 ng/mg protein, respectively) than in ulcerous patients (6.9 +/- 1.98 ng/mg protein and 1.75 +/- 1.23 ng/mg protein, respectively). However, when antibodies to somatostatin and vasoactive intestinal polypeptide (VIP) were added together to the culture media, in ulcerous patients, EGF levels also were lower as absolute values, but were higher as a percentage of variation than controls (p less than 0.05). The fall of EGF secretion from tissue cultures of ulcerous patients could be the consequence of endocrine cellular loss or damage, rather than the cause of ulceration. Moreover, the EGF-producing cells around the lesion in ulcerous patients seems to be hyperactive, and this hyperfunction of EGF-producing cells might contribute to the in vivo repair of tissue damage.

Role of vasoactive intestinal polypeptide (VIP) and endogenous somatostatin on the secretion of epidermal growth factor (EGF): studies on duodenal tissue cultures

Epidermal Growth Factor (EGF)-containing cells have been found in Brunner's glands in the same area where several regulatory peptides are released. The present study was aimed at testing the release and the regulation of EGF secretion from cultured duodenal biopsies obtained from healthy individuals by gastroscopy. The effects and the interaction of VIP and somatostatin on the hormone release were studied. Duodenal biopsies were cultured at 37 degrees C in Mc Coy's buffer, gassed with 95% O2 and 5% CO2. After 30 min, the culture medium was decanted for the measurement of the hormones by RIA. To measure the protein content, the tissue was then homogenized; EGF detected in the culture was 11.5 ng/mg protein. The addition of VIP in the medium increased EGF mean levels to 21.6 ng/mg protein (P less than 0.01). The biopsies thus obtained were cultured with anti-somatostatin antibodies to evaluate the influence of endogenous somatostatin on EGF secretion. The inclusion of anti-somatostatin antibodies increased the EGF levels to 41.2 ng/mg protein (P less than 0.01). The combined addition of anti-somatostatin antibodies and VIP in the culture caused a mean EGF increase significantly higher than the values obtained separately by VIP and somatostatin (P less than 0.01). In conclusion, we can suggest a triangular interaction model of EGF release, where the somatostatin seems to be the negative monitor of over-secreted VIP and EGF from the gut.

Seroepidemiology of measles in Catalonia (Spain) 1985-1986

A seroepidemiological study of measles immunological status was carried out among four different populations: schoolchildren of 6-7 years, 10-11 years and 13-14 years, and pregnant women of 18-45 years, in Catalonia, Spain; 1,213 children and 239 pregnant women were surveyed. The measurement of measles antibodies were made by indirect immunofluorescence, with antibody titres greater than or equal to 1:8 considered as positive. The prevalence of measles antibodies was 82.9% in the 6-7 year old group, 87.2% in the 10-11 year old group and 94.4% in the age group 13-14 years. Among pregnant women, the prevalence of antibodies was 96.2%. Two of the variables studied were associated with the prevalence of measles antibodies in schoolchildren: the disease antecedents and measles vaccination. In pregnant women aged 18-45 no variable had any statistically significant association with the prevalence of measles antibodies.

[Cuff pressure in intratracheal tubes. Evaluation of the new Mallinckrodt-Brandt model]

Cuff pressure of endotracheal tubes increases to dangerous levels during anesthesia with nitrous oxide. In a small clinical study the Authors conclude that Mallinckrodt-Brandt endotracheal tubes are the only "low pressure" tubes available at the moment.

The induction phase of neuromuscular block after suxamethonium and pancuronium: analysis of the time constant of single-twitch decay (tau T1)

The T1% (first unconditioned stimulus of train-of-four) decay was analysed in 55 patients paralysed with different doses of suxamethonium and pancuronium during minor elective ear and nose surgery. In patients given pancuronium, T1% decay is well described by a mono-exponential function: a semi-log plot of ln(T1%) versus time is in fact a straight line. Predicted values are quite comparable with mean and individual values recorded in patients. From these equations the time-constant of single-twitch decay, or tau T1, may be calculated easily: it is a good dynamic descriptor of the speed of onset of neuromuscular block. In patients paralysed with suxamethonium, the rapidly developing block makes it difficult to acquire a sufficient number of data for computation of regression lines: while T1% seems to decrease exponentially, as in the pancuronium groups, no definite conclusions are possible at present. The authors conclude that tau T1 may be a useful dynamic descriptor of neuromuscular block induced by non-depolarizing muscular blocking drugs. Two new concepts are introduced: (i) the time spent to overcome the 'margin of safety' of neuromuscular transmission, or T MOS; and (ii) the speed index, as a measure of the relative speed of the onset of block.

Analysis of microdifferentiation in a Spanish cellar population of Drosophila melanogaster

Variation in Adh and alpha Gpdh-1 gene frequencies has been used to check for microdifferentiation in Spanish samples of Drosophila melanogaster inside and outside a wine cellar. Flies were collected after vintage and after overwintering respectively; within each period samples were taken on up to five consecutive days each month. Variation of gene frequencies of Adh and alpha Gpdh-1 can be considered random when samples collected each month are taken into account. When mean monthly frequencies are considered, alpha Gpdh-1 does not show any significant variation all over the year; yet, variation of the frequency of AdhS shows a cyclical pattern, its frequency being maximum at the end of the summer and minimum after overwintering. Due to the parallel change of the frequency of the inversion In(2L)t and the AdhS allele, no decision can be made whether the Adh locus itself or the inversion are responsible for the changes.