PubMed Health⌕ Search

Biomedical subjects

C A Henry

Publications and source records attributed to C A Henry.

At least 19 recordsLinked to original sources
PubMed1995

Sensitivity of Porphyromonas and Prevotella species in liquid media to argon laser.

The phototoxicity of argon laser irradiation was studied in aqueous suspensions of Porphyromonas endodontalis (American Type Culture Collection [ATCC] 35406), Porphyromonas gingivalis (ATCC 33277), Prevotella denticola (ATCC 33184) and two strains of Prevotella intermedia (ATCC 15033 and 49046), all "black-pigmented bacteria," BPB, that accumulate cellular porphyrins. Several of these species have been implicated in the etiology of periodontal disease. Non-black-pigmented bacteria were also studied to test the specificity of irradiation as a potential photodynamic treatment for periodontal infections. Cell suspensions were irradiated with an argon laser at fluences of 20-200 J/cm2. When cultured in hemin-supplemented media, ATCC 15033 was the most sensitive to irradiation. However, a second strain of the same species (ATCC 49046) was resistant. The photosensitivity of other species ranked ATCC 33277 > 35406 = 33184 = 35496. When hemin was replaced in media by hemoglobin, ATCC 33277 became resistant to irradiation. Protoporphyrin IX content in BPB cells was shown not to be a major factor determining photosensitivity. Oxygen was required during irradiation for BPB species to be affected. Non-black-pigmented bacteria were much less sensitive to irradiation than BPB.

Argon↗
PubMed1992

Antibacterial activity of dental implant metals.

This study was conducted to investigate the specific in vitro antibacterial effect of seven dental implant metals on oral bacteria which have often been identified in failing implants. The metals chosen for evaluation were titanium, chromium, cobalt, aluminum, iron, gold, and vanadium. These metals were selected because they are contained in many commonly used dental implants. The bacteria selected for this study included isolates of Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella melaniogenica, Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, and Actinomyces viscosus. Sets of tubes containing either supplemented trypticase soy broth, brain-heart infusion-yeast extract, or brain-heart infusion-yeast extract with 5 percent defibrinated rabbit blood were aseptically prepared with doubling dilutions of the seven metals starting at an initial concentration of 500 micrograms/ml and terminating at 0 microgram/ml. Cultures of each organism were inoculated into each set of broth tubes containing all concentrations of metals. Tubes were incubated either anaerobically or in an atmosphere of 5 percent carbon dioxide for 48 hours at 35 degrees C and then assayed for ATP content which was proportional to the viable cellular biomass. The results showed that, although being bacteria and concentration dependent, all seven metals suppressed the growth of each organism. The rank order of antibacterial activity expressed by dental implant metals was gold > titanium > cobalt > vanadium > aluminum > chromium > iron.

Actinomyces↗
PubMed1992

Serum glucose: effects on tumor and normal tissue accumulation of 2-[F-18]-fluoro-2-deoxy-D-glucose in rodents with mammary carcinoma.

The positron-emitter-labeled glucose analogue 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) accumulates into many cancers after intravenous injection, but the effect of serum glucose levels on FDG uptake in the tumor has not been extensively studied. In vitro, elevated media glucose levels markedly diminished FDG and FDG 6-phosphate uptake and retention in human adenocarcinoma cells, while insulin had no effect. Mammary cancers were established subcutaneously in 12 rats. Six control rats with mammary tumors were fasted overnight. Hyperglycemia was established in six rats by means of continuous glucose infusion (glucose clamp). All animals were then intravenously administered 50 microCi of FDG. Serum glucose levels were 87 mg/dL (4.83 mmol/L) in the control animals and more than 900 mg/dL (49.9 mmol/L) in the hyperglycemic animals. One hour after injection of FDG, mean F-18 uptake in the tumor, brain, small bowel, and ovaries was 2.7-9.7 times lower in the hyperglycemic animals (P less than .02). Mean F-18 activity in the kidneys tended to be somewhat higher in the hyperglycemic animals. FDG uptake in other tissues was comparable between the control and hyperglycemic groups. These data suggest that high serum glucose levels may substantially impair visceral tumor imaging with FDG positron emission tomography.

Animals↗
PubMed1992

Aiding the novice practitioner in contact lens selection.

A comprehensive study was performed to assist the new graduate and novice contact lens practitioner in the choice of the optimal lens for each case scenario, as well as provide guidance for inventory selection. The survey was distributed to the clinical staff at the State University of New York, State College of Optometry, in order to take advantage of the knowledge of the experienced contact lens fitter. There appear to be clinically significant relationships between lens characteristics and performance ratings.

Contact Lenses↗
PubMed1991

Improved monoclonal antibody tumor/background ratios with exchange transfusions.

Blood exchange transfusions were performed in nude rats with subcutaneous HTB77 human ovarian carcinoma xenografts in an attempt to improve specific monoclonal antibody (MoAb) tumor/non-tumor uptake ratios. Animals were injected intravenously with both 131I-5G6.4 specific and 125I-UPC-10 non-specific MoAb. Twenty-four hours later 65-80% of the original blood was exchanged with normal heparinized rat blood and then these rodents were sacrificed. Exchange transfusion significantly (P less than 0.05) decreased normal tissue activities of 131I (except for muscle) by 63-85%, while tumor activity decreased only 5%. Tumor to background ratios increased from 0.1-0.8 to 2.3-6.3. Exchange transfusions substantially enhance tumor/normal tissue antibody uptake ratios and, along with plasmapheresis, may be useful in enhancing antibody localization in vivo, particularly for therapy.

Animals↗
PubMed1990

Comparison of the antimicrobial effectiveness of regular and fresh scent Clorox.

The antimicrobial properties of two different compositions of sodium hypochlorite were compared in a tube dilution study. Absorbent paper points were contaminated with Streptococcus faecalis or Candida albicans and exposed to 5.25% or 2.62% concentrations of "regular" or "fresh scent" sodium hypochlorite (Clorox) for periods ranging from 15 to 120 s. The points were then removed from the sodium hypochlorite solution, placed into a growth medium, incubated, and the presence or absence of growth recorded. Results showed that formulary changes involved in the manufacture of the "fresh scent" sodium hypochlorite had no apparent effect on its antimicrobial properties, as both compositions proved equally effective against the test organisms at each concentration evaluated.

Candida albicans↗
PubMed1990

Determinants of acute hemodynamic and electrophysiologic effects of verapamil in humans: role of myocardial drug uptake.

To examine the relationship between myocardial verapamil content (MVC) and acute effects in humans, coronary sinus catheterization was used in 22 patients to determine myocardial uptake of verapamil after bolus intravenous (i.v.) verapamil (4 mg) injection. Verapamil-induced effects on hemodynamic and electrophysiologic parameters were measured simultaneously and correlated with MVC per unit baseline coronary sinus blood flow (MVC:F). Myocardial uptake of verapamil was rapid: peak MVC (1.2 +/- 0.2% of injected dose) occurred at 5.4 +/- 0.4 min; at 30 min, residual MVC was 71.1 +/- 3.4% of maximum. Peak MVC:F in individual patients was inversely related to the extent of coronary artery disease (p less than 0.005) but not to left ventricular (LV) systolic function. Verapamil produced significant (p less than 0.001) early reductions in arterial pressure and systemic vascular resistance (SVR); cardiac index (CI) increased, left ventricular (LV) positive dP/dt was unchanged. Verapamil prolonged (p less than 0.01) PR and AH intervals (maximum at 12-18 min) and atrioventricular (AV) nodal effective and functional refractory periods (ERP, FRP) (maximum at 30 min). In individual patients, the extent of changes in AH intervals (r = 0.69; p less than 0.05) and LV dP/dt (r = 0.62; p less than 0.05) correlated with peak MVC:F. We conclude that after i.v. injection, verapamil uptake by the human myocardium is rapid and more extensive in patients with minor coronary artery disease. Despite the hysteresis between MVC and drug effects, MCV is a determinant of inotropic and electrophysiologic effects of verapamil.

Adult↗
PubMed1990

Bactericidal effects of human neutrophils and sera on selected endodontic pathogenic bacteria in an anaerobic environment.

Phagocytosis by normal human neutrophils and the bactericidal activity of normal human pooled serum were measured under anaerobic conditions on six endodontic pathogenic bacterial species from the genera Actinomyces, Bacteroides, Fusobacterium, Peptostreptococcus and Streptococcus. The results revealed that Actinomyces viscosus was not killed either by human neutrophils or by 20 per cent serum; Peptostreptococcus anaerobius was not killed by either 20 per cent or 95 per cent serum; and Bacteroides intermedius was susceptible to both 20 per cent and 95 per cent serum, but was not killed by neutrophils after exposure for 20 minutes. The other species showed intermediate susceptibility patterns. Such results suggest that oral pathogens vary with regard to the bactericidal effects of these two host defense mechanisms, and that this variation may at least in part explain the relative quantities of microbes recovered in certain oral infections.

Actinomyces↗
PubMed1990

Central infusion of aldosterone increases blood pressure by mechanisms independent of Na retention.

Experiments were performed to test the hypothesis that Na retention and Na in the diet are not required to initiate central aldosterone induced hypertension. Rats were fed either standard rat chow or Na-deficient diet and infused intracerebroventricularly (i.c.v.) with aldosterone (28 ng/h) dissolved in artificial cerebrospinal fluid (vehicle) or vehicle alone. In Na-replete rats the central infusion of aldosterone did not promote Na or water retention, prior to increases in systolic blood pressure (SBP). Infusion of aldosterone in Na-deficient rats also initiated a rise in SBP, although the response was delayed. In neither group of rats did aldosterone infusion significantly change plasma Na, K, renin, norepinephrine (NE) or vasopressin (AVP) concentrations. There was no significant increase in plasma aldosterone concentration in Na replete rats centrally infused with aldosterone. Infusion of vehicle had no effect on SBP. We conclude that central aldosterone infusion initiates an increase in blood pressure by a mechanism independent of Na retention. Furthermore, increased concentrations of systemic renin, vasopressin, and activation of the sympathetic nervous system do not appear to be involved in maintaining hypertension.

Aldosterone↗
PubMed1988

Nitroglycerine/N-acetylcysteine in the management of unstable angina pectoris.

N-acetylcysteine (NAC) has been shown to potentiate the haemodynamic and antiplatelet effects of nitroglycerine (NTG) in man, and to limit the development of haemodynamic tolerance to NTG. These effects may be mediated. by the formation of S-nitroso-NAC, which induces vasodilation and strongly inhibits platelet aggregation. In a randomized double-blind study in 46 patients with severe unstable angina pectoris unresponsive to standard treatment (including cutaneous nitrates and calcium antagonists in 45 patients) we compared the effects of intravenous (IV) NTG with those of IV NTG combined with IV NAC (5 g 6 hourly). Treatment with NTG/NAC (24 patients) was associated with a similar frequency of episodes of chest pain as treatment with NTG alone (22 patients), but somewhat fewer increments in infusion rate for pain control (10 vs 17; P NS). The NTG/NAC group had a significantly lower incidence of acute myocardial infarction than the NTG/placebo group (3 vs 10 patients; P = 0.013). Symptomatic hypotension occurred frequently in the NTG/NAC group (7 vs 0 patients; P = 0.006). It is concluded that combined administration of NTG and NAC in patients with unstable angina pectoris may augment the clinical efficacy of NTG, largely by reducing the incidence of acute myocardial infarction. However, the high incidence of severe hypotension with NTG/NAC suggests that this regimen should be used with some caution.

Acetylcysteine↗
PubMed1988

Combined use of nitroglycerin and N-acetylcysteine in the management of unstable angina pectoris.

The vasodilator effects of nitroglycerin (NTG) are mediated via activation of guanylate cyclase; this process is believed to require the availability of free sulfhydryl groups. Previous studies in man have shown that the sulfhydryl donor N-acetylcysteine (NAC) potentiates the systemic and coronary vasodilator effects of NTG. Furthermore, interaction of NTG and NAC may lead to the formation of S-nitroso-NAC, which strongly inhibits platelet aggregation. The effects of intravenous NTG combined with intravenous NAC (5 g 6 hourly) were compared with those of intravenous NTG alone in a double-blind trial in 46 patients with severe unstable angina pectoris unresponsive to conventional treatment, which included calcium antagonists and cutaneous nitrates in all but one patient. Treatment with NTG/NAC (24 patients) and that with NTG alone (22 patients) was associated with a similar frequency of episodes of chest pain and of increments in NTG infusion rate for pain control (10 vs 17; p = NS). The NTG/NAC group had a significantly lower incidence of acute myocardial infarction than the NTG/placebo group (three vs 10 patients; p = .013). Symptomatic hypotension occurred frequently in the NTG/NAC group (seven vs 0 patients; p = .006). Lactate-pyruvate ratios and venous NTG concentrations were not significantly affected by NAC. Subsequently, another 20 consecutive patients were treated with intravenous NTG and continuously infused NAC (10 g/day). Seven remained pain free during the first 24 hr of NTG infusion; 11 required increments in NTG infusion rate for pain control. Acute myocardial infarction occurred in one patient, while none developed symptomatic hypotension.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1988

Primary lymphoma of the large intestine.

Three cases of primary colonic lymphoma are presented and the literature for this disease is reviewed. Colonic lymphoma occurs in from 0.5 to 2 per cent of all cases of neoplastic disease of the colon, and comprises 15 to 20 per cent of cases of primary gastrointestinal lymphoma. The disease can occur at any age, from 3 years to 89 years; the average age is 50 years. Men are affected twice as often as women. The disease most commonly presents as a painful abdominal mass. The cecum is the area of involvement in 70 per cent of cases. The tumors are usually large, averaging over 7 centimeters. The most common histological types are histiocytic or lymphocytic tumors. Surgery is the principle treatment mode; about half are thought to be potentially curable at the time of surgical exploration. The role of adjuvant therapy has not yet been clearly defined, although data from some studies indicate increased survival in those patients given adjuvant radiation therapy. Survival is decreased in patients with tumors larger than 5 centimeters or with histiocytic cell type. Overall 5-year survival is 39 per cent.

Aged↗
PubMed1987

Isolation of hepatocytes from postnatal mice.

A method for the isolation of hepatocytes from postnatal (1- to 3-week-old) mice has been developed. Cell isolation was carried out by retrograde perfusion of the liver with a collagenase-containing bicarbonate buffer. Viable cells were separated by selective adsorption onto collagen membranes. Cell viability was assessed by measuring ATP and glutathione content, lactate:pyruvate ratio, and the rate of protein synthesis. Comparisons of these parameters were made with those in cells isolated from adult mice and with values in whole liver. These hepatocytes were capable of metabolizing acetaminophen to its known hepatic conjugates and were susceptible to acetaminophen toxicity. This procedure for isolating mouse hepatocytes should be useful for the study of hepatic drug metabolism and its relationship to toxicity in the postnatal mouse.

Acetaminophen↗
PubMed1987

Relationships of serum opsonins and complement in human experimental gingivitis.

This study assessed the phagocytosis of polymorphonuclear neutrophils and the opsonic capacity of serum in experimental human gingivitis. Relationships were sought among these two measurements, clinical indices of gingivitis and complement-related opsonins. Measurements of chemiluminescence provided an index of phagocytosis and of opsonic capacity. Test group Plaque Index scores were higher than the control group on Days 7, 14, and 21, while the Gingival Index of the test group was elevated only on Day 21. Phagocytosis of test subjects' PMNs and opsonic capacity of their sera were no different from that of the controls'. Levels of C3 in both nonactivated and activated sera of the test group were significantly lower than that of the control group only on Day 14. In the test group, differences of per cent C3 conversion occurred between Days 14 and 21, and Plaque Index scores were inversely correlated with the order of per cent C3 data on these same days. Our results also indicate that complement contributes significantly to the serum opsonic capacity. The levels of developing plaque and subsequent gingival inflammation are apparently related to the degree of complement activation.

Adult↗
PubMed1985

Microbiology teaching in American dental schools.

A comprehensive questionnaire on current practices relevant to teaching microbiology to dental students was sent to all dental schools in the United States. The survey collected information on resources available, modes of teaching, and evaluation processes. Seventy percent (42/60) of the schools responded. Great variation was found in the teaching of microbiology largely due to the variety of educational resources, perspective of subject matter by the faculty, and the backgrounds of entering students. Data are presented that document the integration of microbiology with other courses, placement of microbiology in the curriculum, class attendance policies, availability of advanced selective and/or elective courses, and National Board reviews. These and other data indicate some prevailing trends in the teaching of microbiology to dental students.

Curriculum↗