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Biomedical subjects

D Forman

Publications and source records attributed to D Forman.

At least 145 records · Page 8Linked to original sources
PubMed1991

Endogenous nitrosation of L-proline by dietary-derived nitrate.

Two studies were conducted to assess the availability of normal dietary sources of nitrate for endogenous nitrosation of an amino acid substrate, L-proline, and to investigate the potential for dietary ascorbic acid to inhibit such nitrosation. In the first study, 16 subjects consumed a salad meal (containing about 172 mg nitrate) with and without a loading dose of proline. A significant increase (10.8 compared with 2.7 micrograms/24 hrs, p less than 0.0001) in mean urinary N-nitrosoproline (NPRO) excretion following meal plus substrate ingestion was indicative of intragastric proline nitrosation by meal-derived nitrate. In the second study (19 different subjects), the mean urinary NPRO level was significantly decreased (15.8 micrograms compared with 28.4, p = 0.022) by inclusion of ascorbic acid sources in the meal. This demonstrated inhibition of proline nitrosation by dietary sources of the vitamin. Large interindividual variation in nitrosating ability was apparent that was associated with variation in meal nitrate to salivary nitrite conversion. Although meals containing fresh vegetables, as tested here, could provide sufficient nitrate to result in endogenous formation of N-nitroso compounds, there will be considerable inter- and intraindividual variation in the extent of this process.

Administration, Oral↗
PubMed1991

Helicobacter pylori infection rates in relation to age and social class in a population of Welsh men.

The seroprevalence of IgG antibodies to Helicobacter pylori was determined using a standard enzyme linked immunosorbent assay in a population of 749 randomly selected men, aged 30-75 years, from Caerphilly, South Wales. The overall prevalence of H pylori was 56.9%, increasing sharply in middle age from 29.8% in those aged 30-34 to over 59% in those aged 45 or older (p less than 0.0001). Age standardised seroprevalence rates were lowest in combined social class categories I and II (49.2%), intermediate in categories IIIN and M (57.5%), and highest in categories IV and V (62.2%) (p = 0.01). In those aged 30-34 years, the prevalence rate for those in combined social class categories IV and V was 57.9% - double the rate for social class categories IIIM and N (28.3%) and five times the prevalence rate in those in social class categories I and II (11.1%). These differences in the infection patterns of H pylori by social class are consistent with patterns of peptic ulcer disease and gastric cancer.

Adult↗
PubMed1991

The N-nitrosoproline test as a measure of cancer risk in geographical comparison studies: results from Italy and an overall comparison.

The N-nitrosoproline (NPRO) test has been used in studies in which populations at high risk of cancer have been compared with equivalent populations at lower risk, to examine whether the geographical variation in cancer risk correlates with propensity for endogenous nitrosation, as assessed by the NPRO test. The usual method employed has been to determine NPRO in 12- or 24-h urine samples, after ingestion of L-proline, in a representative sample of the general population. We present results from one such geographical study conducted in two regions of Italy (Florence and Cagliari) with an approximately three-fold variation in gastric cancer mortality. The nonsignificant difference in mean NPRO excretion between the two populations was insufficient to explain the difference in cancer risk. The fact that there are appreciable international differences in formation of NPRO suggests, firstly, that nitrosation may be of relevance to cancer risk in some countries but not in others and, secondly, that variations within one country may not be large enough for significant geographical differences to be evident. Multivariate analysis of individual, rather than grouped, results from our Italian study made it possible to quantify the relevance of different factors to NPRO formation: a major factor is exposure to nitrate. Important relationships may be missed by analysing only grouped data.

Humans↗
PubMed1991

The etiology of gastric cancer.

We review recent evidence concerning risk factors for gastric cancer. An overview of analytical studies shows convincing evidence of a protective effect of fruit and vegetables. The specific protective constituents have not been firmly established, but micronutrients, especially ascorbic acid, are probably of importance. Other dietary factors that show a consistent pattern of effect in different studies are the moderate risks associated with high intake of preserved foods and salt. Evidence also indicates that gastric cancer is associated with tobacco consumption, although even in continuing heavy smokers the risk does not exceed two fold. Another non-dietary factor of potential importance is infection with the bacterium, Helicobacter (Campylobacter) pylori. The model of Correa and co-workers currently offers the best working hypothesis to explain the etiology of gastric cancer. Although the endogenous synthesis of N-nitroso compounds is central to the model, it is not yet clear what the rate-limiting steps are. Exposure to nitrate per se does not directly cause gastric cancer.

Animals↗
PubMed1990

Geographic association of Helicobacter pylori antibody prevalence and gastric cancer mortality in rural China.

To examine the geographic association between Helicobacter pylori infection and gastric cancer, we have assessed the prevalence of IgG antibodies to H. pylori in plasma samples taken in 1983 from 1882 men, aged 35-64 years, in 46 rural counties of the People's Republic of China. The gastric cancer mortality rates in these countries in 1973-75 varied from 3 per 1,000 (cumulative rate, 0-64 years) to 69 per 1,000, while the proportions of the population positive for H. pylori antibodies (based on an average of about 41 men per county) varied from 28% to 96%. After correction for the limited number of blood samples per county, the estimated correlation between H. pylori antibody prevalence and gastric cancer mortality was 40% (p = 0.02). No other type of cancer showed a significant association with H. pylori.

Adult↗
PubMed1990

Liver transplantation for acute hepatic failure?

In the absence of definitive medical treatment for severe fulminant hepatic failure, liver transplantation may be appropriate in selected patients. However, uniform and easily applicable criteria for diagnosis of severity and analysis of results are needed to prevent unnecessary transplantation and to ensure that patients who may benefit are appropriately treated. Previous regimens for treatment of fulminant hepatic failure were often advocated, on the basis of data from historical controls, for several years until controlled trials failed to show any benefit. To obtain reliable information more rapidly than achieved before, a controlled trial between specialist liver transplant units is needed to establish the role of emergency hepatic transplantation in patients with fulminant hepatic failure.

Acute Disease↗
PubMed1990

Microembolization and resection of a highly vascular pyogenic granuloma.

An unusual case is reported of a hypervascular pyogenic granuloma arising from the mandible which continued to grow postpartum in a person with an associated port-wine nevus. Microembolization of the lesions permitted complete surgical removal with minimal blood loss. This case supports the theory of arteriovenous anastomosis being associated with the pathogenesis of pyogenic granulomas.

Adult↗
PubMed1990

Nitrate and nitrite exposure in Italian populations with different gastric cancer rates.

Exposure to nitrate and nitrite from dietary sources was estimated by questionnaire and measurement of salivary levels of the ions in residents of four regions of Italy with longstanding, contrasting, gastric cancer mortality rates. Whether using salivary levels or dietary questionnaire estimations no association was found between nitrate and nitrite exposure and gastric cancer mortality rates. For salivary nitrate and nitrite, the intra-provincial variation was greater than any inter-province difference. However, for dietary nitrate and nitrite intakes, there were significant differences between the regional groups (but not related to gastric cancer risk). Despite the limitations of the methods used, there was a weak positive association between salivary concentrations of nitrate and questionnaire assessment. Dietary factors are likely to play key roles at different stages of the gastric carcinogenic process. Nitrate may play a part but is unlikely to be a rate-limiting factor in all individuals or populations.

Adolescent↗
PubMed1990

The prevalence and characteristics of congenital pigmented lesions in newborn babies in Oxford.

Melanocytic naevi (MN) are recognised risk factors for malignant melanoma but the epidemiology of MN is poorly understood. Some MN are present at birth and the study of congenital lesions is an important first step toward understanding the development of MN in early life. In this study, the prevalence and characteristics of congenital pigmented lesions were documented in 1012 White caucasian newborn babies at a maternity hospital in Oxford. Only 12 babies (1.2%) were found to have pigmented skin marks and each of these had only one lesion and no other abnormalities. MN were identified with certainty in only five babies (0.5% of the population; 95% CI, 0.06%-0.93%) thus confirming the relatively low prevalence of this lesion. Four of the MN were noted to be 'small' (less than 15 mm diameter) and all five were less than or equal to 20 mm in diameter. In other respects, the MN displayed a diversity of features. Of the other lesions there were two Mongolian blue spots, one melanocytic pustule, one 'probable' MN and three unusual skin marks where the diagnosis was uncertain but considered unlikely to be MN. During the course of the study, examinations were also carried out incidentally on 39 non-White babies. Twenty-two of these were noted to have Mongolian spots (57%) and three had other pigmented lesions (8%).

England↗
PubMed1990

Success with temporomandibular joint arthroscopic surgery.

Although most new surgical procedures are criticized during their embryonic stages of development, TMJ arthroscopy should be considered with a great deal of respect when used. Owing to its proximity to the brain, ear, and major nerves and vessels in the facial region, all TMJ surgery has been looked upon as a "last resort" in treating TMJ dysfunction. This has been the case with open arthrotomies and is the case, at this time, with arthroscopy. The goal of TMJ therapy has always been to recapture the disk or surgically reposition it. In TMJ arthroscopy, this entire concept has, for the most part, been abandoned. All that most surgeons desire to accomplish with TMJ arthroscopy is breaking up of adhesions, lavaging out the joint space, and obtaining joint mobility. Most of the pioneers in open TMJ surgery are reporting excellent results with TMJ arthroscopy. TMJ arthroscopy is not meant for all TMJ disorders. When used in the appropriate situation, success in the hands of the experienced surgeon seems inevitable. One of the greatest concerns is "Who is trained to provide this service and how does one become properly trained?" The answer to this is being formulated by such conferences as the yearly International Conference on TMJ Arthroscopic Surgery and by all of the major TMJ surgeons worldwide. Also, courses have been designed to provide cadaver experience. Of course, if a surgeon is not trained or is poorly trained in this procedure, a catastrophe could most likely ensue.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthroscopes↗
PubMed1989

Sexual behaviour of young and middle aged men in England and Wales.

Establishing patterns of sexual behaviour is essential in predicting the future spread of HIV. The sexual behaviour patterns of a randomly selected sample of 480 white men aged 15 to 49 were obtained by interview and analysed in relation to age, social class, and area of residence. Over half of the men had first had intercourse before the age of 18 and over three quarters had done so before the age of 20. Age at first intercourse tended to be lower in more recent birth cohorts and in social classes III, IV, and V. Men in earlier birth cohorts tended to have had fewer heterosexual partners, both regular and casual, than those born more recently, but there were no social class or regional differences in the number of partners. Eight of the 480 men (1.7%, 95% confidence interval 1.1 to 2.3%) stated that they had had homosexual intercourse, four of whom had had one casual homosexual partner. Only one man had had more than 25 homosexual partners. The number of men having had homosexual intercourse was lower than is widely thought. When possible, data were checked with national data or other surveys and thought to be accurate. The difficulties in collecting data of this nature are discussed.

Adolescent↗
PubMed1989

Geographical variation in mortality from leukaemia and other cancers in England and Wales in relation to proximity to nuclear installations, 1969-78.

The distribution of mortality from 11 causes of death (lymphoid leukaemia, other leukaemia, leukaemia of all types, Hodgkin's disease, other lymphomas, all lymphomas, multiple myeloma, lung cancer, other malignancies, all malignancies and all other causes) has been examined in three age groups throughout England and Wales over the period 1969-78. The reorganisation of local authority administration in 1974 meant that the smallest areas that could be examined were 400 county districts or (in some cases) approximate county districts formed by aggregating pre-1974 local authority areas. The variation in the numbers of deaths observed about the numbers expected was assessed using log-linear models to estimate the effect on the relative risk in each district associated with social class, rural status, population size, health authority region and proximity to one of 15 nuclear installations. Trends in risk with increasing proximity to an installation (as judged by the proportion of the population resident within 10 miles) were examined after adjustment for the other four variables. The results showed that in districts near to an installation there were significant excess mortalities in persons under 25 years of age from leukaemia (RR = 1.15, P = 0.01) and especially from lymphoid leukaemia (RR 1.21, P = 0.01) and from Hodgkin's disease (RR 1.24, P = 0.05) and a significant deficiency of mortality from lymphoid leukaemia in persons aged 25-64 years. No significant trends were observed with an increasing proportion of the population near to the installations and the greatest excess mortality from lymphoid leukaemia in young persons was observed in the districts with the intermediate proportion of the population (10.0-65.9%) near an installation.

Adolescent↗
PubMed1989

Swift increase in alcohol metabolism in humans.

One hundred and fifteen human male subjects, 19-30 years of age, received ethanol orally as vodka (0.55, 0.7, or 0.85 g/kg) followed by a second drink (0.3-0.4 g/kg) given 3-4 hr later. After both doses, blood ethanol levels reached approximately 100 mg/dl. Breath samples were taken every 20-30 min and rates of ethanol elimination were determined. In addition to the design described above, 100 subjects received 0.7 g/kg ethanol in two separate visits to the laboratory. In a third experimental design, ethanol was given i.v. to 12 subjects. With the single-day experimental design, the frequency distribution of changes in rates of ethanol elimination between the first compared with the second administration of ethanol was not unimodal. Up to 20% of the subjects demonstrated rates more than 40% greater than basal values in response to ethanol. Based on these findings in humans, a Swift Increase in Alcohol Metabolism (SIAM) was defined as an increase in the rate of ethanol elimination of at least 40% over the basal rate. Under these conditions, the frequency of SIAM was dose dependent (studied with 0.55, 0.7, and 0.85 g/kg); nearly 20% of the subjects demonstrated SIAM with a dose of ethanol of 0.85 g/kg. In the two-day experimental design, a SIAM response was also observed in about 10% of 49 well-fed subjects; however, none of 51 subjects tested exhibited a SIAM response following an overnight fast. In addition, a rapid and transient SIAM reflecting a 60% increase in the rate of ethanol elimination above basal values was observed when ethanol was given continuously for 5 hr i.v.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗