Biomedical subjects
Publications and source records attributed to H W Kaufman.
Following a carefully thought-through battle plan helps uncover and defuse the treacherous mines that dot the ground ahead. "Generals" of the laboratory are advised to take the long view.
Thermal, tactile, osmotic, and electrical stimuli, as well as exposure to air, can each elicit a painful response in individuals with hypersensitive teeth, and thus provide the basis for the different methods used to measure dentinal hypersensitivity. Tactile methods range from simple use of a sharp dental explorer to devices that can quantify the probing or scratching pressure exerted generally along the cementoenamel junction. Thermal methods involve flow of air or metal probes applied in different ways. Electrical stimulus is more complex and generally consists of progressive elevation of the magnitude of the stimulus until a sense of prepain rather than pain is felt. More than one method is usually needed in order to assess dentinal hypersensitivity, which has been estimated to affect one in every seven patients that visit a dental office.
Gestational diabetes occurs in 3 to 6 percent of pregnancies and is associated with increased rates of macrosomia, serious birth trauma and cesarean section. Neonatal hyperbilirubinemia, hypocalcemia and hypoglycemia also occur more frequently in this disorder. Perinatal outcome is improved through the identification and management of affected women. It is therefore recommended that all pregnant women be screened for this condition at 24 to 28 weeks of gestation. In addition to plasma glucose levels, a new measurement of glycemic control--the serum fructosamine level--may prove useful in identifying and managing women with gestational diabetes.
The usefulness of lactate dehydrogenase (LD) and LD isoenzymes in the diagnosis of acute myocardial infarction (AMI) is controversial. The present study reviewed 507 consecutive patients in whom creatine kinase, creatine kinase isoenzymes, LD and LD isoenzymes were ordered over a 1-month period. Of these, 249 had an insufficient number of serial enzyme determinations to establish a laboratory diagnosis of AMI. After excluding an additional 11 patients for other reasons, 247 patients remained for analysis. Of these, only 2 (0.8%) had myocardial infarction by standard clinical criteria with normal creatine kinase and creatine kinase-MB but elevated LD and abnormal LD isoenzymes. Seven patients (7 of 247, 2.8%) had false-positive LD isoenzymes. Thus, the routine use of LD and LD isoenzymes was of no use in most patients (96%) and led to the incorrect diagnosis of AMI more than 3 times as often as it helped with a correct diagnosis. Total 1-month charges for all the LD and LD isoenzymes obtained equalled +42,450. Therefore, it appears that LD and LD isoenzymes are not routinely useful in the diagnosis of AMI and may result in considerable unnecessary expense. It is suggested that LD and LD isoenzymes be ordered only under suspicion of late presentation (greater than 48 hours) of AMI.
Streptococcus mutans GS5, Lactobacillus casei DSM20011 and Actinomyces viscosus T14 produce artificial caries in the roots of extracted teeth. Roots were coated with wax leaving an 8 mm2 window exposed on the buccal surfaces, and then incubated for 8 days in the presence of the test organism, the synthetic medium being changed each day. Samples were then examined by SEM, or microradiographs were obtained from 120 microns sections. The pH at the root surface at the end of the induction averaged 4.43, 5.00 and 5.20, and the lesion depths measured on the microradiographs averaged 121, 83 and 34 microns, for Strep. mutans, L. casei and A. viscosus respectively. This relationship between pH and lesion depth confirms earlier findings. As all of these organisms can produce lesions in tooth structure, elimination of one type would probably not eliminate caries.
A 66-year old acquired immunodeficiency syndrome (AIDS) patient presented with cutaneous lesions suspicious for Kaposi's sarcoma. Biopsies disclosed granulomatous infiltrates with acid-fast bacilli and cytomegalovirus inclusions within macrophages and endothelial cells in one biopsy. Herpesvirus vesicle, necrotizing folliculitis, and vasculitis were observed in a second biopsy taken concurrently. These findings emphasize the polymorphous presentation of infectious disorders in AIDS and the need for multiple biopsies and for work-up with special stains in these patients.
This study examines chemically and histologically the relative abilities of inositol monophosphate (IP1), inorganic phosphate (Pi), ethane-1-hydroxy-1, 1-diphosphonate (EHDP) and dichloromethylene disphosphonate (Cl2MDP) to inhibit parathyroid hormone (PTH)--induced resorption of fetal rat long bones in organ culture. Pregnant rats injected with 45Ca on the 18th day of gestation were killed the next day and their fetuses removed. Half of each pair of dissected long bones was incubated in a chemically defined control medium while the contralateral half was incubated in medium containing PTH or PTH plus the compound to be tested. 45Ca released into the medium was indicative of the amount of bone resorption. Bones were then processed histologically and examined microscopically. All compounds inhibited resorption to some extent with IP1 and Pi being less effective than EHDP or C12MDP at comparable phosphate concentrations. However, the disphosphonates damaged osteoclasts whereas IP1 and Pi did not. This suggests that IP1 may inhibit resorption by a different mechanism perhaps related only to prevention of crystal dissolution.
Eleven postmenopausal complete denture patients participated in a study to evaluate some possible predictors of osteoporosis. Most participants in the study reported a low caloric intake and consumed considerably less than the recommended daily allowances of sodium, cholesterol, calcium, fluoride, magnesium, zinc, and folic acid. Many participants in the study were taking additional daily vitamin and mineral supplements. The CCT as measured on radiographs of the second phalynx of the fifth digit of the right hand correlated linearly with the CBD corrected for soft tissue. Panoramic radiographs revealed that all individuals had severe residual ridge resorption. All serum calcium and phosphorus means were within the normal range, while more than 60% of the patients had below normal plasma levels of 25-hydroxyvitamin D. In conclusion, although based on a small sample, it appears that the diet of elderly women in New York is somewhat deficient for adequate skeletal homeostasis. Ideally, the vitamin D status of each patient should be determined and proper supplements prescribed. However, the high cost of analysis suggests that dietary analysis be used on a selected but more frequent basis. Radiation techniques for measuring skeletal porosity are also too complex to perform on a routine basis and should, like dietary analysis, be reserved for patients in whom other clinical signs and symptoms indicate metabolic bone disease.
This study assesses the abilities of S. mutans GS5 and BHT and S. sanguis G9B to produce subsurface lesions on smooth surfaces of extracted human teeth and examines factors which might be responsible for any differences encountered. Teeth were incubated in Brain Heart Infusion broth containing 2% sucrose and a pure culture of the organism to be tested, the media being changed each day for eight days. Surface and media pH's were measured. The mineral content of both the surface enamel and the subsurface lesions was determined by contact microradiography. Significantly deeper and more demineralized lesions were produced by GS5 than by either BHT or G9B. GS5 also produced a lower surface and medium pH and a more dense coating on the teeth. Similar results were obtained with GS5 and G9B when the BHI broth was replaced with FMC synthetic media. It is concluded that the system described is suitable for studying cariogenic potential and will be useful in measuring the anticariogenicity of suspected therapeutic agents.
This study investigates the ability of phytic acid, its inositol phosphate derivatives (inositol penta-, tetra-, tri-, di-, and monophosphate), and inorganic phosphate to inhibit parathyroid hormone (PTH)-induced resorption of fetal rat long bones in organ culture. Pregnant rats injected with 45Ca on the 18th day of gestation were killed the next day and their fetuses removed. Half of each pair of dissected long bones was incubated in a chemically defined control medium, while the contralateral half was incubated in medium containing PTH or PTH plus the phosphate compound to be tested. 45Ca released into the medium was indicative of the amount of bone resorption. All phosphate compounds tested inhibited resorption. The inositol phosphates should be studied further to assess their suitability as therapeutic agents for treatment of metabolic bone diseases involving increased turnover.
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The solubility of hydroxyapatite was examined in calcium phosphate mixtures produced by combining Ca(OH)2 and H3PO4 in varying proportions under a wide variety of conditions. Analyses of supernatants for calcium, phosphorus, and pH provided the data for solubility calculations. Alteration of the solid/liquid ratio by removing supernatant or by evacuating water from equilibrated mixtures had little effect on the solubility product. However, when precipitates separated from some mixtures were reequilibrated at various solid/solution ratios in either water, acetate buffer, or supernatants obtained from previous equilibrations, incongruent solubility was demonstrated and was attributed to the formation of other calcium phosphate phases which coated the apatite. The experiments indicated that hydroxyapatite has a thermodynamic solubility product between 10(-57) and 10(-60), but the exact value is difficult to determine because of the formation of surface coats.
Precipitates formed over a 10 day period by adding variable amounts of Ca(OH)2 to H3PO4 were examined chemically and by X-ray diffraction in order to determine and to relate the crystallographic changes observed during calcium phosphate formation in this system to those seen previously in dental plaque. In the lower Ca(OH)2/H3PO4 ratio mixtures the initial precipitates were amorphous or poorly crystalline. The latter deposits showed an apatite-like diffraction pattern which changed to brushite and decreased in Ca/P ratio from approximately 1.2-1.0. Since the amorphous precipitates showed a similar decrease in the Ca/P ratio and a transient appearance of apatite, it was suggested that these initial precipitates, like the poorly crystalline deposits, may contain brushite amorphous to X-rays. Precipitates from the higher Ca(OH)2/H3PO4 ratio mixtures changed from a poorly crystalline to a more crystalline apatite and the Ca/P ratio remained fairly constant. The relation between the pH, Ca and P on the one hand and the brushite and apatite contents and the pattern of crystallization of the precipitates on the other was strikingly similar to the same realtionship observed earlier in dental plaque in situ, suggesting that the system used in this study could be used to study certain aspects of plaque mineralization in vitro.
Upon exposure to laser radiation, enamel powder mixed with NaF underwent an increase in crystallite size and/or perfection with a significant uptake of fluoride. Incisor teeth lased in the presence of NaF released significantly less calcium and phosphorus into sodium acetate (pH 4.0) compared with unlased controls, suggesting a possible role for the laser in caries prevention.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.