A clinical trial of all-ceramic crown restorations: status, fall 1995

Although porcelain-fused-to-metal (PFM) restorations are the most widely used full-coverage crown restoration systems, their inherent properties make the achievement of natural aesthetic restorations an elusive task. In contrast, the all-ceramic system (IPS Empress, Ivoclar North America, Amherst, NY) offers excellent translucency and vitality, without the opacity associated with PFM restorations. Its vitality is further enhanced by an adhesive resin cementation method that conducts the color of the underlying tooth structure. This article reports the status of a 5-year investigation, initiated in 1992, of the clinical performance of the IPS Empress all-ceramic system and the resin cementation system used with it.

The changing availability of residential aged care in Australia

Australian aged care services have undergone a series of substantial reforms in recent years under the rubric of the Aged Care Reform Strategy. Overall, there has been a progressive refinement of the targeting of available services on those most in need, defined in terms of both disability levels and financial resources. A key component of this process has been a deliberate reduction in the relative emphasis accorded to nursing home care within the aged care system. This has been accompanied by increases in the resources directed toward less intensive forms of residential care (hostels) and community based services. This paper explores the actual consequences of these intentional policy changes in terms of the availability of nursing home and hostel care, and the changing characteristics of nursing home residents. The results suggest that a more substantial reduction has occurred in the availability of nursing home care than has hitherto been suggested, with consequent decreases in the proportion of aged persons in nursing homes. The effect has been particularly marked amongst women and the very old. These findings raise policy questions about the appropriateness of current and planned future levels of provision.

Summary of first round cluster analysis: complete antibody panel

The reactivities of 141 monoclonal antibodies (mAbs) with 60 target cell types or lines were analysed by flow cytometry and the data subjected to statistical clustering. mAbs were assigned to 23 clusters by statistical similarity and information on specificity supplied by the contributor. Clustered mAbs were examined in more detail in the second round of workshop analyses.

Prostatic marker-negative amphicrine carcinoma of the prostate

It has been shown that prostatic adenocarcinoma differentiation correlates with prostatic-specific marker and neuroendocrine expression; that is, the more undifferentiated the tumor, the less it expresses prostatic markers and the more neuroendocrine cells are found in it. Complete absence of prostatic markers together with marked neuroendocrine expression has been associated with small cell morphology. This report describes a case of a metastatic, prostatic marker-negative, non-small cell prostatic adenocarcinoma with a prominent neuroendocrine component. The architecturally well-organized luminal-exocrine cells appeared ultrastructurally undifferentiated, however, displaying an almost empty cytoplasm. This contrasted with the prostatic marker-positive control cases of prostatic carcinoma, which contained relatively numerous cytoplasmic vacuoles. The neuroendocrine cells could be identified by light microscopy as eosinophilic cells. The number of the latter cells was markedly increased in the metastatic foci compared with the primary tumor. Light microscopically and ultrastructurally, the eosinophilic cells in this case differed from the Paneth-like cells described in prostatic carcinoma in previous reports. This case provides support for the general concept of multidirectional differentiation in human epithelial cancers and in particular for the association of poor tumor differentiation with neuroendocrine expression in prostatic carcinoma. In addition, in contrast with previous reports describing absence of basement membrane in metastatic foci of prostatic carcinoma, in the current case well-formed basal laminae were identified.

Establishment of the formalin-free surgical pathology laboratory. Utility of an alcohol-based fixative

Concerns about the toxicity of formalin dictate the need for alternative methods of tissue fixation. Alcohol-based fixatives have been proposed as optimal for immunohistochemical and nucleic acid methods and may be useful for diagnostic light microscopy. We recently converted our surgical pathology laboratory from 10% neutral buffered formalin to an alcoholic fixative (56% ethanol and 20% polyethylene glycol) and compared 100 consecutive cases after conversion with 100 formalin-fixed cases prior to conversion. One representative slide from each case was reviewed independently by four pathologists without knowledge of the fixative employed. The quality of fixation of each case was graded (0, very poor; 1, below average; 2, average; and 3, above average) based on the subjective composite evaluation of seven morphological features: tissue architecture, cell borders, cytoplasm, nuclear contours, chromatin texture, red blood cell membranes, and uniformity of staining. No significant difference in the quality of fixation was observed, although the average score of the alcoholic fixative was slightly lower than that of the formalin (2.59 vs 2.74). Interobserver concordance was 74%. Advantages of the alcoholic fixative included elimination of carcinogenic vapors, more rapid fixation, greater stain avidity, elimination of enzyme predigestion in immunohistochemical studies, and simple and rapid disposal. Disadvantages included slightly increased viscosity, increased variability of tissue staining and nuclear shrinkage, artifactual pigment deposition in bloody specimens, and increased flammability risk. Alcohol-polyethylene glycol appears to be a satisfactory alternative to formalin in routine diagnostic surgical pathology.

Bacterial meningitis

Meningitis remains a significant health problem for the older adult population. Although the overall incidence of this disease has decreased in the United States, the incidence of meningitis in the elderly population is increasing. Additionally, the recognition of meningitis in the older adult may be more difficult because the usual symptoms and signs are neither as specific nor as sensitive as they are in a younger population. Newer antibiotics have provided better therapeutic approaches to some of the organisms responsible for this disease, and newer methods of therapy beyond antibiotics hold the promise of altering the unacceptably high morbidity and mortality.

Fissure sealant knowledge and characteristics of parents as a function of their child's sealant status

A survey was conducted to identify and compare sealant knowledge and sources of sealant information of parents whose children had and had not received fissure sealants. The socioeconomic characteristics of these individuals were also compared. The sealant group was composed of the parents of children found to have a sealant on at least one permanent tooth during dental examinations of 2,036 elementary schoolchildren in southwestern Michigan. Another group of children was selected from the same population and matched to the children with sealants by child's age, sex, school location, and community. Surveys were returned by 210 of 260 sets of parents (81% response rate). Significant differences were found between the two groups with regard to parents' ages and levels of income. Parents of children with sealants had more correct information about the procedure and 74 percent of these individuals reported that the dental office was their primary source of information. For the group without sealants, 48 percent of respondents reported no source of sealant information. Findings suggest that dental personnel may strongly influence dissemination of information about sealants and utilization of this preventive procedure.

A stretcher that facilitates the radiographic evaluation and closed reduction of spinal fractures

A rigid and exceptionally radiolucent stretcher with an attachment for cervical traction has been constructed. A patient is able to remain on this stretcher in the same position during the entire radiographic examination of a spinal fracture, including plain x-ray and computed tomographic and myelographic studies. Two advantages are obtained if this stretcher is used: 1) A patient's spine is well supported and does not need to be moved at any time during these radiographic studies, and 2) the application of traction during the myelography or closed reduction of a cervical fracture is facilitated.

Therapy of experimental Pseudomonas endocarditis with high-dose amikacin and ticarcillin

Right-sided infective endocarditis due to Pseudomonas aeruginosa was induced in 130 rabbits. Animals received either: (1) no therapy (controls); (2) standard-dose amikacin (AMK) (15 mg/kg/day) plus ticarcillin (300 mg/kg/day), or (3) high-dose AMK (20 or 25 mg/kg/day) plus ticarcillin, for 20 days. Animals in each treatment group were evaluated at 10 days after therapy for bacteriologic relapse. Both standard- and high-dose AMK regimens significantly decreased mortality and Pseudomonas aeruginosa vegetation titers versus controls (p less than 0.01, p less than 0.05, respectively). Despite significantly higher serum AMK levels at 25 mg/kg/day, there was no significant difference in mean vegetation titers, percent of vegetations sterilized, or posttherapy bacteriologic relapse in the three treatment groups. AMK at 20 or 25 mg/kg/day (but not at 15 mg/kg/day) significantly reduced the incidence of pulmonary infarction versus untreated controls (p less than 0.01).

Synthesis of peptides with the solid phase method. II. Octapeptide analogues of angiotensin II

Forty-six analogues of angiotensin II were obtained with the solid-phase method for peptide synthesis. The peptides were purified, using the conventional procedures; homogeneity and purity were established after paper, thin-layer chromatography, paper electrophoresis, amino acid analysis, elemental analysis, and enzymatic degradation by aminopeptidase. The biological activity of all compounds was compared with that of angiotensin II on the blood pressure of anesthetized rats. The same test was used to establish the antagonistic effect of several analogues against angiotensin II.

Role of the N-terminal amino acid for the biological activities of angiotensin and inhibitory analogues

Aspartic acid was replaced in position 1 of angiotensin II (ATII) with several amino acids, to assess the possible influence of the N-terminal amino acid for (a) the intrinsic activity, (b) the affinity, and (c) the metabolic degradation of agonist analogues of ATII. Some of the substitutions in position 1 were used in combination with replacement of Phe by Gly or Leu in position 8, to obtain the corresponding antagonist.The compounds were tested in vivo (rat blood pressure) and in two in vitro preparations (rat stomach and rabbit aorta strips). The oil immersion technique, described by Kalsner and Nickerson (1968) (Can. J. Physiol. Pharmacol. 46, 719–730), was used to study the disposition of the peptides by vascular smooth muscles (rabbit aorta strips). Degradation of the peptides by purified aminopeptidases was evaluated in vitro by measuring the fragments on paper chromatography. Potency of antagonists was estimated in vivo (ID50) and in vitro (pA2 values): duration of action was established by infusing the inhibitors intravenously into anesthetized rats and testing the effect of standard doses of angiotensin before and after.The results indicate that replacement of Asp with other amino acids does not influence the intrinsic activity, but can either increase or decrease the affinity in vitro or the potency in vivo. 1-Sar-ATII, and 1-D-Ala-ATII are more potent and longer acting than 1-Asp-ATII on isolated intestinal and vascular smooth muscles, but not in vivo. On the contrary, 1-β-Asp-ATII and 1-β-D-Asp-ATII are more potent than 1-Asp-ATIIin vivo, but not on rabbit aorta strips. Rate of relaxation of rabbit aorta strips suspended in oil, after contraction with submaximal doses of several analogues of ATII, are significantly slower than relaxation after 1-Asn2-ATII and 1-Asp-ATII. A close parallelism between the diminution of the relaxation rate in oil and the degradation by aminopeptideses in vitro was observed, suggesting that metabolic degradation may be the major factor determining relaxation of rabbit aorta in oil after contraction with one of these peptides. Potencies of antagonists in vivo and in vitro are increased by replacing Asp with Sar. Substitution of Asp with β-Asp or β-D-Asp brings about a slight increase of potency in vivo but not in vitro. It appears that firm binding and prolonged occupation of receptors by sarcosyl derivatives are the primary factors contributing to increase the potency and to prolong the duration of action of antagonists, while prevention or reduction of metabolic breakdown by aminopeptidases is much less efficient.

Synthesis of peptides by the solid phase method. I. Tetradecapeptide renin substrate and intermediate peptides, nonapeptides, and fragments of angiotensin II

Tetradecapeptide renin substrate (H∙Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser∙OH) (1–14), tridecapeptide (1–13), dodecapeptide (1–12), undecapeptide (1–11), two nonapeptides (1–9) and (1–9-Leu), heptapeptide (1–7), tetrapeptide (1–4), tetrapeptide (5–8), pentapeptide (4–8), hexapeptide (3–8), and heptapeptide (2–8) were synthesized by the solid phase method and by using an improved reaction vessel. The yield averaged 50–70%. Homogeneity and purity of peptides were established with elemental anlysis for C, H, and N, paper chromatography in three solvent systems, electrophoresis, amino acid analysis, and enzymatic degradation by aminopeptidase M.