Biomedical subjects
Publications and source records attributed to J Springer.
What is involved in setting up and managing a decentralized laboratory testing program at a hospital? What elements are involved in making such a program a success? Multidepartmental and multidisciplinary cooperation and communication are the keys to implementing a cost-effective, user-friendly system that assures quality patient care and operator competence.
Self-monitoring of blood glucose (SBGM) is widely recommended for both type 1 and type 2 diabetic patients despite the lack of evidence of benefit in glucose control or as an aid in weight loss in type 2 subjects. This study tested the hypothesis that combined use of SMBG and dietary carbohydrate (CHO) counting, using the blood monitoring results to shape dietary CHO quotas, is beneficial in managing type 2 diabetes. Twenty-three overweight (body mass index, BMI 27.5-44 kg/m2) patients aged 40-75 participated in a 28-week behavioral weight control program. Baseline hemoglobin HbA1c ranged between 9.5% and 13.5% (normal range 5.5%-7.7%). Subjects were matched for weight, sex, and HbA1c and assigned to small (4-8 participants) groups which met weekly for 12 weeks and then monthly for 16 weeks. After 8 weeks, the groups were randomized either to continue the behavioral program or to have SMBG and dietary CHO counting. Glucose monitoring was performed 6 times daily (pre- and 2 h postprandially) for the first month, focusing on the meal increment and correlating this to dietary CHO intake. Weight loss was identical in both groups during the year of follow-up. The HbA1c level showed a progressive decline in experimental subjects (P < 0.05), whereas there was no improvement in control subjects.
Lifetime cancer potency of aflatoxin was assessed based on the Yeh et al. study from China in which both aflatoxin exposure and hepatitis B prevalence were measured. This study provides the best available information for estimating the carcinogenic risk posed by aflatoxin to the U.S. population. Cancer potency of aflatoxin was estimated using a biologically motivated risk assessment model. The best estimate of aflatoxin potency was 9 (mg/kg/day)-1 for individuals negative for hepatitis B and 230 (mg/kg/day)-1 for individuals positive for hepatitis B.
Mortality from lung cancer was greater in Ontario uranium miners than in the general male population of Ontario (observed = 152, expected = 67.6, standardised mortality ratio 225, 95% confidence interval 191-264). Part of the excess of lung cancer may be because the proportion of men who are smokers or have smoked is greater in uranium miners than in Ontario men. Smoking does not explain the whole excess. Mortality from lung cancer in Ontario uranium miners is clearly related to exposure to short lived radon progeny. The excess relative risk of lung cancer from the same degree of exposure to short lived radon progeny is greatest five to 14 years after exposure and less subsequently. It is greater in men under the age of 55 years and less in older men. Part of the excess of lung cancer mortality in Ontario uranium miners is probably also due to exposure to arsenic that occurred earlier in gold mines. In Ontario uranium miners, the lung cancer mortality from exposure to arsenic increases as the intensity of exposure to short lived radon progeny increases. This finding is consistent with the hypothesis that the risk of lung cancer from exposure to arsenic is enhanced by exposure to other carcinogens. In Ontario uranium miners, the proportion of lung cancers that are small cell carcinomas is greater than in the general population. The proportion of small cell carcinomas is especially great five to 14 years after exposure to short lived radon progeny and in men who die from lung cancer at younger ages.
An excess of mortality from stomach cancer has been found in Ontario gold miners (observed (obs) 104, standardised mortality ratio (SMR) 152, 95% confidence interval (95% CI) 125-185) and no excess of stomach cancer could be detected in other miners in Ontario (obs 74, SMR 102, 95% CI 80-128). The excess of stomach cancer appeared five to 19 years after the miners began gold mining in Ontario. In that interval, similar patterns of excess mortality from stomach cancer were found in miners born in north America (obs 14, SMR 268, CI 147-450) and in miners born outside north America (obs 12, SMR 280, 95% CI 145-489). Twenty or more years after the miners began mining gold, an excess of mortality from stomach cancer was found in gold miners born outside of north American (obs 41, SMR 160, 95% CI 115-218) but not in gold miners born in north America (obs 37, SMR 113, 95% CI 80-156). The excess of stomach cancer in gold miners under the age of 60 (obs 45, SMR 167, 95% CI 122-223) seems larger than the excess in gold miners between the ages of 60 and 74 (obs 59, SMR 143, 95% CI 109-184). Exposures to arsenic, chromium, mineral fibre, diesel emissions, and aluminium powder were considered as possible explanations of the excess of stomach cancer in Ontario gold miners. Exposure to diesel emissions and aluminium powder was rejected as gold miners and uranium miners were exposed to both agents but an excess of stomach cancer was noted only in gold miners. The association between the excess of stomach cancer and the time since the miner began mining gold suggested that duration of exposure to dust in gold mines ought to be weighted according to the time since the exposure to dust occurred and that an appropriate time weighting function would be one in the interval five to 19 years after each year of exposure to dust and zero otherwise. A statistically significant association between the relative risk of mortality from stomach cancer and the time weighted duration of exposure to dust in gold mines was found in miners under the age of 60. Time weighted indices of exposure to chromium and arsenic were formed for each gold miner by time weighting the product of the duration of exposure to dust in a gold mine and the percentages of arsenic and chromium in rocks in that gold mine. Exposure to mineral fibre was measured in terms of the time weighted duration of employment in those gold mines that contain mineral fibre. A statistically significant association between the excess of stomach cancer in gold miners under the age of 60 and the time weighted index of exposure to chromium occurred and not association was found between the excess of stomach cancer and either the time weighted duration of employment in mines containing mineral fibre. The excess of stomach cancer in gold miners under the age of 60 was better associated with the time weighted index of exposure to chromium than to the time weighted duration of exposure to dust in gold mines. Although the number of cases of gastric cancer that were classified according to the system of Lauren was small, the data suggest that for miners under the age of 60, exposure to chromium is associated with the development of the intestinal rather than the diffuse type of gastric cancer.
A method is described for preparing mutants with multiple, site-directed mutations by ordered coupling of PCR-generated fragments catalyzed by a thermostable DNA ligase. Annealing of the sense strands of the fragments to a single-stranded (antisense) template created a full-length sense strand leaving only nicks that were closed by ligation. Mutations were introduced in the PCR primers. Following 40 cycles of denaturation and annealing, tags on the flanking primers of the ligase chain reaction product were used specifically to amplify the mutated product with specific primers that could not amplify the original template. The amplified ligation product was cloned and was found to contain the desired restriction sites introduced by way of the mutagenic primers.
The spontaneous and recessive mutation thn in the basidiomycete Schizophyllum commune suppresses the formation of aerial hyphae in the monokaryon and, if present as a double dose, the formation of both aerial hyphae and fruit-bodies in the dikaryon. In the monokaryon, the mutation prevents accumulation of mRNA of the Sc3 gene, and in the dikaryon it also prevents the accumulation of fruiting-specific mRNAs, including mRNAs of the Sc1 and Sc4 genes, which are homologous to the Sc3 gene. These three genes code for hydrophobins, a family of small hydrophobic cysteine-rich proteins. In the thn monokaryon, the only detectable change in synthesized proteins is the disappearance of an abundant protein of apparent Mr = 28 K from the culture medium and from the cell walls. Protein sequencing shows that this is the product of the Sc3 gene. The Sc3 hydrophobin is present in the walls of aerial hyphae as a hot-SDS-insoluble complex. Submerged hyphae excrete large amounts of the hydrophobin into the medium.
A cohort of 54,128 men who worked in Ontario mines was observed for mortality between 1955 and 1986. Most of these men worked in nickel, gold, or uranium mines; a few worked in silver, iron, lead/zinc, or other ore mines. If mortality that occurred after a man had started to mine uranium was excluded, an excess of carcinoma of the lung was found among the 13,603 Ontario gold miners in the study (standardised mortality ratio (SMR) 129, 95% confidence interval (95% CI) 115-145) and in men who began to mine nickel before 1936 (SMR 141, 95% CI 105-184). The excess mortality from lung cancer in the gold miners was confined to men who began gold mining before 1946. No increase in the mortality from carcinoma of the lung was evident in men who began mining gold after the end of 1945, in men who began mining nickel after 1936, or in men who mined ores other than gold, nickel, and uranium. In the gold mines each year of employment before the end of 1945 was associated with a 6.5% increase in mortality from lung cancer 20 or more years after the miner began working the mines (95% CI 1.6-11.4%); each year of employment before the end of 1945 in mines in which the host rock contained 0.1% arsenic was associated with a 3.1% increase in lung cancer 20 years or more after exposure began (95% CI 1.1-5.1%); and each working level month of exposure to radon decay products was associated with a 1.2% increase in mortality from lung cancer five or more years after exposure began (95% CI 0.02-2.4%). A comparison of two models shows that the excess of lung cancer mortality in Ontario gold miners is associated with exposure to high dust concentrations before 1946, with exposure to arsenic before 1946, and with exposure to radon decay products. No association between the increased incidence of carcinoma of the lung in Ontario gold miners and exposure to mineral fibre could be detected. It is concluded that the excess of carcinoma of the lung in Ontario gold miners is probably due to exposure to arsenic and radon decay products.
Spheroidal bladder substitutes made from double-folded ileal segments, similar to Goodwin's cup-patch technique, are devoid of major coordinated wall contractions. This, together with the reservoir's direct anastomosis to the membranous urethra, prevents major intraluminal pressure peaks and assures a residue-free voiding of sterile urine. In order to determine whether, under these conditions, an afferent tubular isoperistaltic ileal segment of 20-cm length protects the upper urinary tract as efficiently as an antireflux nipple, 60 male patients who were subjected to radical cystectomy were prospectively randomised to groups in which a bladder substitute was formed together with either of these 2 antireflux devices. An analysis of the results obtained in 20 patients from each group who could be followed for more than 1 year (median observation time 30 and 36 months) showed no differences between the groups in metabolic disturbances, kidney size, reservoir capacity, diurnal and nocturnal urinary continence, the incidence of urinary tract infection or episodes of acute pyelonephritis. Later than 1 year postoperatively, intravenous urograms of the renoureteral units of 25% of the patients with antireflux nipples showed persistent but generally slight dilatation of the upper urinary tracts. This observation was significantly more frequent than it was in patients with afferent tubular segments. Urodynamic and radiographic studies showed that the competence of the antireflux nipples was secured by the raised surrounding intravesical pressure. This, however, also resulted in a transient functional obstruction, and a gradual rise of the basal pressure in the upper urinary tracts was recorded. In patients with afferent ileal tubular segments, contrast medium could be forced upwards into the renal pelvis when the bladder substitutes were overfilled. However, despite raised intravesical pressures, peristalsis in the isoperistaltic afferent tubular segment gradually returned contrast medium back to the reservoir. Our results suggest that the combination of an ileal low-pressure reservoir together with an afferent tubular isoperistaltic limb is at least as good as an antireflux nipple valve. Moreover, the use of the afferent ileal limb makes it possible to resect the distal and often diseased ureters together with the paraureteric lymphatics at a safe distance from the bladder tumor. This avoids also distal ischemic ureteric stenosis and makes possible a simple end-to-side ureterointestinal anastomosis with a small complication rate.
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This study assessed the impact of various individual symptoms of autism on mothers and fathers, and professionals' accuracy in estimating parents' perceived stress levels. Mothers and fathers of 20 autistic children, and 20 therapists working with those children, independently rated the severity of common symptoms of autism in their child, and how stressful they found each symptom; therapists estimated parental stress. The autistic child's language and cognitive impairment were judged by all raters as most severe and stressful. In contrast with other studies, individual parents agreed on both symptom severity and degree of stress. Parents of older children judged symptom severity to be lower, but fathers reported a continued high level of stress. Professionals judged families as more stressed by the child symptoms than did families themselves. Implications for intervention and casework are discussed.
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This study evaluated objectively the relationship between recent life events, social support systems, and blood glucose control in diabetic patients using both short-term [fasting blood sugar (FBS)] and long-term [glycosylated hemoglobin (Hgb A-1C)] measures of control. We found that a higher number of life events was associated with a higher percentage of abnormal FBS and Hgb A-1C results, and that improved social support was associated with a smaller percentage of abnormal Hgb A-1C scores. These pilot findings are discussed in connection with a biopsychosocial approach to the understanding and management of diabetes mellitus.
Toluene administered by inhalation at 400 ppm to CD-1 mice from Days 6 to 16 of gestation was teratogenic but not fetotoxic resulting in a significant shift in the fetal rib profile. At the lower concentration of 200 ppm, there was an increase in dilated renal pelves which might reflect desynchronization of maturation with respect to development and growth. No other effects were noted at the 200-ppm concentration. At 400 ppm, toluene also produced an increased body weight in the neonates on Day 1 postpartum following in utero exposure. Activity of lactic dehydrogenase (LDH) was significantly increased in the brains of dams exposed to 400 ppm during gestation while nonpregnant adult mice studied concurrently had significant increased activities of LDH in the liver and kidneys of the 400-ppm group. The only change in the isozyme profiles was in the kidneys of the nonpregnant adult mice in which a slight decrease in LDH-2 was observed. No other changes were noted in the dams or pups.
Trichlorfon was evaluated for its teratogenic potential in the CD-1 mouse at doses of 200, 300 or 400 mg/kg/day administered by gavage on days 7-16 of gestation. In the CD-1 mouse, TCF was teratogenic, fetotoxic and lethal at the two highest dose levels which were also maternally lethal. At the lowest dose level which was not maternally lethal, there was a significant decrease in the number of calcified centers in the forepaws and hindpaws indicating fetotoxicity and a delay in maturation. TCF was administered at doses of 50, 100 or 200 mg/kg/day to CD rats by gavage on gestational days 7-19 (study I) or 8-20 (study II). In the CD rat in body study I and II, the highest dose level was maternally lethal. In study I, TCF was teratogenic with a shift in rib profile. In study II, TCF was teratogenic with an increased incidence in malformations of the urinary system. Additionally, TCF was fetotoxic with reduced ossification of the skulls at the lowest and highest dose levels.
The term dominant lethal may be defined as death of the heterozygote arising through multiple chromosomal breaks. The assay is generally conducted by treating male animals, usually mice or rats, acutely (1 dose), subacutely (5 doses), or over the entire period of spermatogenesis. Animals treated acutely or subacutely are mated at weekly intervals to females for a sufficient number of weeks to cover the period of spermatogenesis. Those treated for the entire spermatogenic cycle are mated for 1 or 2 successive weeks at the termination of treatment. Females usually are killed at 14 days of pregnancy and examined for the number of total implantations in the uterus, the number of implantations classified as early deaths, and, in some cases, the number of corpora lutea. The category of early death is the most significant index of dominant lethality. A total of 249 papers were reviewed and 140 chemicals were evaluated. Of the 140 chemicals, 65 were positive by the criteria used by the Work Group in evaluating each publication. The category of "positive" includes those responses of a borderline nature. 99 chemicals were declared negative. There is considerable overlap of chemicals in both categories, which accounts for the incongruity in the total number of chemicals tested and the number considered positive and negative. A total of 44 animal carcinogens have been tested in the dominant lethal assay, 26 of which were positive and 18 negative for a correlation of 59%. The role of the assay should be that of confirming positive results from lower tier chromosomal aberration-detecting systems (confirming in the sense of indicating the ability of the chemical to penetrate gonadal tissue and to produce cytogenetic damage). The dominant lethal assay should not be used as a risk assessment method.