Role of saliva during mastication

The chewing process is necessary to facilitate the digestion of food. For this process not only the grinding of the food by mechanical forces is of importance, but also the penetration of the food with saliva. This last process results in the formation of a smooth foodbolus that can be easily swallowed. In addition, the intimate contact between the fine ground food particles and the salivary digestive enzymes is a prerequisite for a rapid digestion. A high quality of saliva is an essential factor to protect the dental elements against attrition and, on the other hand, to promote the digestion process.     

Immunophenotyping of acute leukemia by flow cytometry: closing the black holes of morphology

The heterogeneity of disease conditions in acute leukemia (AL) requires the most discriminative procedures for a differential diagnostic classification. Selected cases of AL, representative of lineage fidelity, multilineage phenotype and phenotypic switch, are reviewed to document that the diversity of the leukemic cells (lineage involved, maturation stage, aberrant markers), although not always characterizable by morphological differences, is reflected by a variety of immunophenotypes which may be efficiently characterized by flow cytometry to obtain a precise diagnosis.     

The inadequacy of threshold values for preventing lead poisoning in Brazil

This article reviews studies performed since 1975 on the occurrence of central and peripheral neurological manifestations in low-level lead exposure. The review shows that in many workers exposed to lead who present indications of both biological effects and exposure below the limits established by the Brazilian laws, abnormalities are found in peripheral nerve conduction velocity and also in several central nervous system functions. The study thus suggests that the threshold values used in Brazil to confirm lead poisoning should be revised.     

Prospective cohort study of antioxidant vitamin supplement use and the risk of age-related maculopathy

In a prospective cohort study, the authors examined whether self-selection for antioxidant vitamin supplement use affects the incidence of age-related maculopathy. The study population consisted of 21,120 US male physician participants in the Physicians' Health Study I who did not have a diagnosis of age-related maculopathy at baseline (1982). During an average of 12.5 person-years of follow-up, a total of 279 incident cases of age-related maculopathy with vision loss to 20/30 or worse were confirmed by medical record review. In multivariate analysis, as compared with nonusers of supplements, persons who used vitamin E supplements had a possible but nonsignificant 13% reduced risk of age-related maculopathy (relative risk = 0.87, 95 percent confidence interval (CI) 0.53-1.43), while users of multivitamins had a possible but nonsignificant 10% reduced risk (relative risk = 0.90, 95% CI 0.68-1.19). Users of vitamin C supplements had a relative risk of 1.03 (95% CI 0.71-1.50). These observational data suggest that among persons who self-select for supplemental use of antioxidant vitamin C or E or multivitamins, large reductions in the risk of age-related maculopathy are unlikely. Randomized trial data are accumulating to enable reliable detection of the existence of more plausible small-to-moderate benefits of these agents alone and in combination on age-related maculopathy.     

The effect of physician office visits on CHD risk factor modification as part of a worksite cholesterol screening program

BACKGROUND: Elevated serum cholesterol is a major risk factor for CHD. Primary prevention through behavioral modification has been designated first-line treatment for patients with elevated cholesterol. In this study, we assessed the impact of a physician office visit after a worksite cholesterol screening on self-reported changes in diet, weight loss, exercise, and smoking. We hypothesized that those individuals who had a physician office visit regarding cholesterol would make more changes in CHD risk factors than those who did not have such a visit. METHODS: A cohort of 4,928 participants from 33 work-sites in Massachusetts and Rhode Island had baseline CHD risk factors evaluated at a cholesterol screening and 4,473 were available at follow-up 6 months later by telephone interview. A total of 1,957 had elevated cholesterol levels (>/=200 mg;/dl) and were instructed to visit their physician, in addition to receiving educational materials related to CHD risk factor modification. RESULTS: Most individuals with elevated cholesterol levels had other prevalent self-reported CHD risk factors at baseline: 58% consumed high-fat diets (>30% fat), 43% were overweight, 60% had a sedentary lifestyle (sweat-related physical activity <3 x per week), and 22% were cigarette smokers. After 6 months of follow-up, 74% of participants with high-fat diets reported eating a lower fat diet, 71% of overweight participants reported weight loss, 53% of sedentary participants attempted to increase physical activity, and 38% of smokers decreased or quit cigarette smoking. Thirty-five percent of participants completed the referral for a physician office visit to discuss their elevated cholesterol determined at the baseline worksite screening. However, these individuals showed only a modest change (which was not statistically significant) in self-reported CHD risk factors compared with those who did not have follow-up physician visits after adjusting for age, sex, race, education, occupation, medical insurance, time since last doctor visit, diabetes, and hypertension. Objective measurements of serum cholesterol, body mass index, and dietary score were likewise modestly improved and not statistically significant. CONCLUSIONS: In 6 months of follow-up, high absolute levels of CHD risk factor modification were observed after a worksite cholesterol screening. A physician office visit added only a modest but not statistically significant benefit for further CHD risk factor modification. These findings indicate that the follow-up cholesterol-related physician visit had little added clinical benefit over the screening intervention alone.     

Dietary NaC1 during pregnancy and lactation: effect on brain angiotensin II receptors and behavior

Female rats were fed diets containing either a basal (0.12%), mid- (1%) or high (3%) level of NaCl during pregnancy and lactation. Plasma aldosterone was elevated approximately 5- and 15-fold in dams fed basal compared with either the mid- or high-NaCl diets at the end of both pregnancy and lactation (Postnatal Day 21), respectively. Dams fed basal diet and killed at the end of lactation had a higher density of angiotensin II receptors in the organum vasculosum laminae terminalis, paraventricular hypothalamus, and median preoptic nucleus than did rats fed either mid- or high-NaCl diets. Other dams, treated identically, were returned to rodent chow (approximately 0.2% NaCl) at the end of lactation for intake tests during the next week. Dams that had received basal diet did not differ from mid-NaCl and high-NaCl groups in sodium appetite induced by either acute sodium depletion or mineralocorticoid administration but showed the lowest spontaneous intake of NaCl solution.     

Ossifying lipoma

 Lipomas are very common, but osseous changes within these tumours are rare. A lipoma with osseous components is presented, with an overview of the literature and pathogenesis of this unusual lesion and considerations relating to the differential diagnosis. Received: 28 July 1998 / Accepted: 27 August 1998     

First transmission electron micrograph of continuous mitotic spindle fibers between polar area and chromosome ends

Congenital and/or nevoid skin disorders following the lines of Blaschko may have a delayed onset after birth. They have to be differentiated from acquired dermatoses exhibiting the same linear pattern. In common dermatoses, such as psoriasis or lichen planus, lesions in a blaschkolinear distribution most often occur together with scattered lesions, but occasionally they may be isolated. Less common self-limited dermatoses such as lichen striatus and adult blaschkitis always present in a blaschkolinear fashion. In these diseases, or some other conditions occasionally distributed along these lines (chronic graft versus host reaction, fixed drug eruption, lupus erythematosus, atopic dermatitis, etc.), the cause of the disease may lead to the unmasking of tolerance to an abnormal keratinocyte clone that remained hidden in these lines. In addition to epithelial cells, other cells may be involved in the occurrence of acquired blaschkolinear dermatoses. In linear atrophoderma and linear fibromatosis, the histogenesis seems to involve hypothetic dermal clones. The extension of an acquired dermatosis on a preexisting linear nevoid disorder is an argument in favor of an early embryonic somatic mutation of a skin cell line.     

Human leptomeningeal and cortical vascular anatomy of the cerebral cortex at 8 Tesla

PURPOSE: The purpose of this work was to describe the human leptomeningeal and cortical vascular anatomy as seen at high resolution on an 8 T UHFMRI system. METHOD: With a 1024 x 1024 matrix, axial gradient echo images of the cerebral cortex were acquired on a human volunteer at 8 T with TR 500 ms, TE 16 ms, flip angle 22.5 degrees, bandwidth 53 kHz, and slice thickness 2.84 mm. The same subject was evaluated at 1.5 T using similar parameters. The images were then reviewed in detail and compared with known cortical and leptomeningeal vascular anatomy. RESULTS: Two hundred forty micron in-plane resolution images of the human brain were acquired at 8 T without evident artifact from susceptibility distortions, RF penetration, or dielectric resonances. The CSF, gray matter, and white matter structures were well discerned. The microscopic leptomeningeal vascular anatomy was well visualized, and the course of small perforating cortical vessels could be followed from the cortical surface to the white matter junction. CONCLUSION: Initial 8 T images of the brain demonstrate detailed leptomeningeal and cortical vascular anatomy.