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Biomedical subjects

A Vassallo

Publications and source records attributed to A Vassallo.

At least 19 recordsLinked to original sources
PubMed1996

Volumetric reconstruction and stereotactic computer assisted resection in intracerebral lesions.

Since 1990 112 patients have undergone stereotactic resection of intra-axial tumoural lesions with volumetric reconstruction, using the Kelly-Goerss system. Stereotactic integration of CT, angiographic and particularly MRI information, together with three-dimensional information of the lesion, provide an innovative evaluation of the most appropriate surgical approach, even for each single patient. The main limitation of this surgical method is in cases where the infiltrating part of the tumour is pre-eminent, while it can allow "macroscopically complete resection" of well circumscribed lesions, almost independently of their location and volume. Some technical aspects of stereotactic resection of brain tumours are discussed in the light of our experience.

Adolescent↗
PubMed1996

Evaluation of 24-hour gastric acidity in patients with hepatic cirrhosis.

BACKGROUND/AIMS: Data from previous studies on gastric acid secretion in patients with hepatic cirrhosis are controversial, due, at least in part, to the possible interference of liver failure and altered gastric mucosal microcirculation on the pharmacological action of the substances used to stimulate the parietal cell. For this reason, we wished to investigate the circadian pattern of gastric acidity by means of continuous 24-hour pH monitoring, which permits measurement of pH fluctuations in a nearly physiological manner and does not require any pharmacological stimulus. METHODS: Forty-nine patients with liver cirrhosis of different aetiology were recruited for this study. They underwent 24-hour gastric pH-metry with an electrode positioned in the gastric corpus, and their pattern of gastric acidity was compared with that of 49 healthy subjects, matched for age and sex. In a subgroup of 31 patients with cirrhosis, antral pH was recorded in addition to body pH in order to assess whether there are regional differences in gastric acidity. RESULTS: The circadian, daytime and nocturnal gastric acidity in patients with cirrhosis was significantly lower (p < 0.05-0.001) than that of controls. In the 31 patients studied with two electrodes, antral pH was higher (p < 0.05) than body pH only during the night. The prevalence of Helicobacter pylori infection was rather low (42%) in our patients. CONCLUSIONS: There is a marked hypoacidity over the circadian cycle in patients with cirrhosis compared to controls, and the greatest difference between them is visible during the nocturnal hours. Also, in patients with liver cirrhosis the pH in the antrum is higher than that in the body of the stomach during the night for reasons that need to be elucidated.

Adult↗
PubMed1996

Stereotactic aspiration and drainage of brain abscesses. Experience with 9 cases.

The first-line treatment for brain abscesses is still a much-debated argument. Recently, stereotactic aspiration of these lesions has gained ground as a valid alternative to the traditional medical and/or surgical therapeutical treatments. From 1991 to 1995, 9 patients affected by intracranial abscesses were surgically treated by stereotactic puncture of the lesion and drainage of pus, using the Kelly-Goerss stereotactic system. Multiple abscesses were present in one case. Specific antibiotic therapy was used in the post-operative stage, when possible. One death occurred four weeks after surgery for acute ischemia of the brain stem. Follow-up CT demonstrated gradual resolution of the abscesses in all the cases and a successful return to normal daily life in all the surviving patients. In one case, recurrence of the abscess occurred two months after resolution: a successful result was obtained by steroids and broad-spectrum antibiotic therapy alone. Possible advantages of this technique are discussed and compared with the traditional routes. The literature concerning this argument is reviewed.

Adolescent↗
PubMed1996

Are duodenal ulcer seasonal fluctuations paralleled by seasonal changes in 24-hour gastric acidity and Helicobacter pylori infection?

The occurrence of duodenal ulcer is characterized by seasonal variation, for poorly understood reasons. No previous study has assessed whether 24-h intragastric acidity and Helicobacter pylori infection have similar seasonal fluctuations in patients with this disorder. For this reason, we evaluated retrospectively the circadian gastric pH in 319 new patients (226 men and 93 women, mean age 45.2 years) with endoscopically proven duodenal ulcer, who agreed to undergo this examination during the years 1987-1992 in our center. The month-by-month occurrence of the disease over the global 6-year period was assessed, and the mean pH values were calculated for each patient during three time intervals of interest: 24 h, daytime (08:00-19:59 h), and nighttime (20:00-07:59 h). The mean pH values of these three time periods were then calculated month by month throughout the annual cycle. H. pylori infection was sought by histology in 171 patients examined in the period from 1990 to 1992. The percentage of H. pylori-positive duodenal ulcer patients was then calculated for each season. The calendar fluctuation of duodenal ulcer occurrence showed an evident increase (p < 0.001) in fall (October-December) and in winter (January-March) compared with spring (April-June) and summer (July-September). Both 24-h and nighttime gastric acidity showed no significant variation by month, whereas daytime gastric pH varied significantly (p < 0.05) with two evident decreases, meaning higher acidity, in April and August. H. pylori infection was detected in 152 of 171 patients (89%), and the percentage of H. pylori-positive duodenal ulcers did not differ from season to season. We conclude that there was no parallel circannual fluctuation of duodenal ulcer, gastric acidity, and H. pylori infection in the restricted sample of patients we studied. This reduces the apparent relevance of acid in inducing ulcer seasonal fluctuation. Also, the responsibility of H. pylori in this phenomenon can be excluded until a reliable diagnostic method capable of distinguishing recent from old infection is found.

Adult↗
PubMed1996

Circadian gastric acidity in Helicobacter pylori positive ulcer patients with and without gastric metaplasia in the duodenum.

BACKGROUND: The presence of gastric metaplasia allows helicobacter pylori to colonise the duodenum and this condition is thought to be acquired as a response to acid hypersecretion. This functional disorder, however, is present only in a subgroup of duodenal ulcer patients and, in addition, surface gastric metaplasia has been frequently found in the proximal duodenum of normal subjects and patients with non-ulcer dyspepsia, who cannot be certainly considered as acid hypersecretors. AIMS: To clarify the role of acid in inducing gastric type epithelium in the duodenum. This study aimed at assessing whether the pattern of circadian gastric acidity differs between H pylori positive duodenal ulcer patients with and without duodenal gastric metaplasia. PATIENTS: Seventy one patients with duodenal ulcer confirmed by endoscopy and who were found to be positive for H pylori infection by histology on antrum biopsy specimens were enrolled into this study. METHODS: Gastric type epithelium in the duodenum was found in 49 of 71 ulcer patients (69%). Continuous 24 hour gastric pH metry was performed in 50 healthy subjects and in the two subgroups of duodenal ulcer patients with and without gastric metaplasia in the duodenum. Gastric acidity was calculated for 24 hours (1700-1659), night (2000-0759) and day-time (0800-1959). RESULTS: Ulcer patients without gastric metaplasia showed a significantly higher gastric acidity (p < 0.001) than controls for every time interval considered, while the ulcer subgroup with gastric metaplasia was more acid than healthy subjects (p < 0.001) during the whole 24 hour period and the daytime. There was no difference between the two subgroups of duodenal ulcer patients with and without gastric metaplasia during the various time segments analysed. CONCLUSION: The findings confirm that the circadian gastric acidity of duodenal ulcer patients is higher than that of controls. As there is no difference in gastric pH between duodenal ulcer patients with and without gastric metaplasia, gastric hyperacidity is not specific to patients with duodenal gastric metaplasia. It is probable that this histological change is a non-specific response to mucosal injury resulting from various factors and not exclusively to acid.

Adult↗
PubMed1994

Urbanization gradients and cancer mortality in Uruguay, 1988-1992.

Cancer deaths occurring in Uruguay in the period 1988-1992 were classified by site, sex and residence according to the ninth version of the International Classification of Diseases (ICD-9), in order to analyze gradients of urbanization. For this purpose, Uruguayan counties were classified as rural, suburban and urban, using population density as an ordinal indicator of the degree of urbanization. Significant increasing trends with urban excess were observed for cancers of the colon, rectum, lung and female breast. In addition, this study showed significant urban deficits for esophageal, gastric and uterine cancers, contrasting with previous studies. These differences seem to be real rather than artifactual due to misclassification. The study thus provides interesting new findings concerning urban differences between developed communities and a partially developing country.

Adolescent↗
PubMed1994

Bolus infusion of famotidine: effects on gastric pH by repeated 12-hour doses of 20 mg in postoperative patients.

This study was carried out to assess the efficacy of intravenous (IV) famotidine in suppressing gastric secretion over a 48-hour period. Twenty postoperative patients requiring a nasogastric tube received famotidine 20 mg IV every 12 hours and gastric pH was measured continuously by means of an indwelling probe. A baseline recording was performed over the first 4 hours and then the drug was infused every 12 hours (q12h) over a 15-minute period for the subsequent 48 hours. The mean pH value achieved during each time segment under active treatment was significantly higher (P < .001) than the mean basal value. Also the density distributions of minutes spent at the various pH units confirm that famotidine is highly effective (P < .001) in raising and maintaining gastric pH above 4.0 units during most of the drug-related period (44 hours). It can be concluded that repeated intravenous boli of famotidine 20 mg every 12 hours allow us to obtain an effective control of intragastric acidity. The antisecretory action is consistent over the total 48-hour period examined and therefore the use of intermittent infusion of famotidine seems to be advisable, as opposed to the recommended continuous IV administration of cimetidine and ranitidine. There is, however, a considerable intersubject variability in the antisecretory response to the drug.

Adolescent↗
PubMed1994

Antisecretory effects of three omeprazole regimens for maintenance treatment in duodenal ulcer.

This study was carried out to assess the antisecretory effects and their possible changes over time of three different dose regimens of omeprazole that could be proposed for maintenance treatment in duodenal ulcer. Forty-five patients with endoscopically proven duodenal ulcer were studied by means of 24-hr gastric pH-metry both in basal conditions and on the fifth day of acute treatment with omeprazole 20 mg in the morning. Ulcers healed after four weeks (in three cases after eight weeks) and afterwards, 15 patients were randomized to receive orally at 0800 hr in single-blind fashion omeprazole 10 mg daily (group A), 15 to receive omeprazole 40 mg on Saturday and Sunday followed by a five-day period without medication (group B), and 15 to receive omeprazole 20 mg every other day (group C) for up to three months. On the 20th and 80th days of these maintenance treatments 24-hr gastric pH-metry was repeated to assess the antisecretory effectiveness of each regimen over a two-month period. In patients of group B these tests began at 1700 hr on Friday, the last of five days off treatment, and in those of group C at 1700 hr of the day off medication. All three dose regimens of omeprazole were able to raise pH values significantly (P < 0.01-0.001) compared to basal levels. Omeprazole 20 mg every other day was more effective (P < 0.01) than omeprazole 40 mg weekend, but did not differ significantly from omeprazole 10 mg daily. The durations of acid inhibition (pH > 3.0 units/24 hr) were 12.44, 10.00, and 17.38 hr with groups A, B, and C, respectively. There was no significant difference between the pH profiles of the 20th and 80th days with every dose regimen. It is concluded that all three dose regimens of omeprazole are effective in reducing gastric acidity and their pharmacodynamic action does not change with time. Therefore they are suitable to be assessed in large clinical trials aimed at verifying the prevention of duodenal ulcer recurrence for longer periods.

Administration, Oral↗
PubMed1993

Antisecretory effect of three premeal doses of cimetidine 400 mg versus a single morning dose of omeprazole 20 mg: pathophysiological implications for duodenal ulcer treatment.

The success of omeprazole in the healing of duodenal ulcer has been attributed to its profound and almost around-the-clock inhibition of acid, but the relevance of reducing meal-stimulated acid secretion exclusively has recently been emphasized in several clinical trials. For this reason, we used 24-h continuous intragastric pH monitoring to compare the pharmacodynamic effects of placebo, three fractioned premeal doses of cimetidine 400 mg and omeprazole 20 mg mane. Fifteen patients with duodenal ulcer in clinical remission were randomized to receive the above medications in single-blind fashion on three separate occasions, at least 2 wk apart. Both active regimens produced higher pH values (p < 0.05-0.001) than placebo, but omeprazole was much more effective than cimetidine (p < 0.01-0.001) during the various time intervals analyzed (24 h, evening, nighttime, daytime). The greater effectiveness of omeprazole was confirmed by its longer-lasting antisecretory action, insofar as the drug increased gastric pH above 3.0 units for about 21 h, whereas the daytime cimetidine regimen maintained this threshold for 7.30 h (p < 0.001) over the circadian cycle. As these markedly different pharmacodynamic effects have been proven to produce similar fast rates of duodenal ulcer healing in clinical trials, it is reasonable to assume that a small but well addressed reduction of gastric acidity can ensure the same therapeutic benefit as a strong and continuous acid inhibition. In this light, the acid peaks in response to meals seem to be important pathophysiological events, whose control is sufficient to permit quick ulcer healing.

Adult↗
PubMed1991

Low physical activity and worsening of glucose tolerance: results from a 2-year follow-up of a population sample in Malta.

The relationship between the level of habitual physical activity and glucose intolerance was examined cross-sectionally and during a 2-year follow-up among a sample of 388 subjects in Malta. At baseline, the subjects were classified into three categories of physical activity, which was inversely related to the 2-h post challenge blood glucose (P = 0.02). In a multivariate analysis, age (standardized regression coefficient 0.23; P less than 0.001), family history of diabetes (0.20; P less than 0.001), and physical activity (-0.18; P = 0.002) were the strongest predictors of the 2-h blood glucose at baseline. The age standardized 2-year risk of glucose intolerance, i.e. impaired glucose tolerance or diabetes was consistently and inversely related to the level of physical activity. Among subjects with normal glucose tolerance at baseline (n = 127) those with low physical activity had a 2.7 times higher risk of glucose intolerance during follow-up than those with high physical activity (P = 0.1), and even a 3.7-fold risk of glucose intolerance at baseline (n = 196) when both the subjects with normal and impaired glucose tolerance at baseline were considered together (P = 0.005). Similar trends were observed for the risk of diabetes. The suggested protective effect of physical activity was independent of body mass, a family history of diabetes and gender. Within the limits of this small study we conclude that physical activity may have some importance in the primary prevention of impaired glucose tolerance and, possibly, non-insulin-dependent diabetes mellitus.

Adolescent↗
PubMed1990

Cancer in migrants to Uruguay.

Mortality rates from different cancers in the principal groups of migrants to Uruguay are compared with those in their countries of origin (Argentina, Brazil, Italy and Spain) and in the Uruguay-born population. Oesophageal cancer is very common in Uruguay and European-born populations, initially at low risk, appear to acquire rather higher rates after migration. For most migrants, the mortality from cancers of the breast, colon-rectum, corpus uteri and prostate is closer to the moderately elevated rates of Uruguay than those in their countries of origin. The results suggest that migrants to Uruguay undergo changes in some important environmental exposures, probably dietary, which give rise to substantial alterations in cancer risk within their lifespan.

Age Factors↗
PubMed1988

Trends in mortality from major non-communicable diseases in the middle-aged population of Malta.

Trends in life expectancy and mortality from major non-communicable diseases in Malta were analyzed from the national vital statistics available. Most of the increased life expectancy during the 20th century in Malta took place between 1930 and 1960 and since then only a minor increase was observed. The peak in age standardized total mortality in men and women aged 40-69 years was during 1974-76. Total mortality in men was about 40% higher than that of women. The proportion of deaths from major non-communicable diseases (cardiovascular diseases, cancer and diabetes) of all deaths increased during 1968-82. In 1983-84 in the age group 45-64 cardiovascular diseases accounted for 54% of deaths in men and 43% in women, cancer 27% and 34%, and diabetes 3% and 11% in men and women, respectively. The international comparison of mortality data showed that mortality from both cardiovascular diseases, cancer and diabetes was clearly higher than in other European Mediterranean countries ranking among the highest in the whole Europe. Public health intervention programmes have initiated in Malta to reduce these high death rates in the future.

Cardiovascular Diseases↗
PubMed1985

Esophageal cancer in Uruguay: a case-control study.

Esophageal cancer has constituted a major public health problem in Uruguay, with age-adjusted death rates of 14.5 X 10(5) for males and of 3.8 X 10(5) for females. A case-control study was undertaken to ascertain the possible association of the local custom of drinking infusions of Ilex paraguariensis ("maté") with cancer of the esophagus, after controlling for well-known risk factors, such as alcohol and tobacco consumption. Two hundred twenty-six patients with esophageal cancer and 469 controls (control:case = 2.1) were interviewed at the time of admission or consultation at the Oncology Institute of Montevideo from 1979 through 1984. Males showed elevated risks of esophageal cancer associated with heavy tobacco [relative risk (RR) = 10.8] and alcohol (RR = 10.3) exposures. Among females, the independent effects of tobacco and alcohol were nonsignificant. Maté consumption had an independent effect in both males and females, with odds ratios of 6.5 and 34.6, respectively, for heavy users. Moreover, a well-defined dose response was evident in both sexes.

Adult↗
PubMed1983

Exposure to lead and cadmium of the general population of Malta.

The blood levels of lead (PbB), cadmium (CdB), and zinc protoporphyrin (ZPP) were determined in 538 Maltese adult subjects. A relatively high level exposure to both metals was discovered. For lead, the median value is 274 micrograms/l with percentile 90 and 98 respectively 564 and 863 micrograms/l. These values are to be compared with the reference values proposed by a directive of the European Community, respectively 200, 300 and 350 micrograms/l. For cadmium, the median value is 2.2 micrograms/l with percentile 90 and 98 respectively 3.8 and 5.7 micrograms/l. These values are compared with those of a Belgian population which are respectively 1.7, 2.6 and 4.3 micrograms/l. The causes of this relatively high exposure are not known. A few tentative hypotheses, which are to be investigated, are made.

Adolescent↗