The duration of ambulatory visits to physicians

BACKGROUND: The objective of our study was to determine the typical length of ambulatory visits to a nationally representative sample of primary care physicians, and the patient, physician, practice, and visit characteristics affecting duration of visit. METHODS: We used an analysis of cross-sectional survey data to determine duration of visit and the characteristics associated with it. The data sources were a random sample of the 19,192 visits by adults to 686 primary care physicians contained in the 1991-1992 National Ambulatory Medical Care Survey, and the results of the Physician Induction Interview conducted by the National Center for Health Statistics. Duration of visit was defined as the total time spent in face-to-face contact with the physician. RESULTS: Mean duration of visit was 16.3 minutes (standard deviation = 9.7). Multivariate analysis allowed the calculation of the independent effect on visit length of a variety of characteristics of patients, physicians, organizational/practice setting, geographic location, and visit content. Certain patient characteristics (increasing age and the presence of psychosocial problems) were associated with increased duration of visit. Visit content was also associated with increased duration, including ordering or performing 4 or more diagnostic tests (71% increase), Papanicolaou smears (34%), ambulatory surgical procedures (34%), patient admission to the hospital (32%), and 3 preventive screening tests (25%). Reduced duration of visit was associated with availability of non-physician support personnel and health maintenance organization and Medicaid insurance. CONCLUSIONS: Multiple factors affect duration of visit. Clinicians, policymakers, and health system managers should take these considerations into account in managing physician resources during daily ambulatory practice.     

Alkaline phosphatase and peptidase levels in invertebrate cartilage

Summary Cartilage is encountered in the skeletons of many advanced invertebrates, yet it never calcifies or is replaced by bone. In an attempt to account for the absence of bone in invertebrates, we tested a hypothesis proposing that absence or inadequate quantities of several enzymes associated with vertebrate osteogenesis may underlie the failure of the invertebrates to evolve bone. The enzymes examined were alkaline phosphatase, alanyl -naphthylamidase, and neutral protease. Their activities were measured in the gill cartilage of the Atlantic horseshoe crab, Limulus polyphemus, and the odontophore cartilage of the marine whelk, Busycon canaliculatum. Animals were collected from the Cape Cod area. Samples of cartilage of Limulus perichondrium, various nonskeletal tissues, and neonatal rat calvaria, the latter as a reference standard, were homogenized in 0.1 M phosphate buffer (pH 7.1) and analyzed for protein content and the above-mentioned enzyme activities. Alkaline phosphatase specific activity was readily detected in most tissues except the invertebrate cartilage specimens in which it was present only at near-trace levels. Naphthylamidase and protease activities were present in all tissues. In a single experiment, higher phosphatase values were recorded for Limulus cartilage retaining perichondrium, but in a subsequent trial assaying cartilage retaining perichondrium, denuded cartilage, and isolated perichondrium separately, it was demonstrated that phosphatase activity resided primarily within the perichondrium. Exposure of thick cryostat sections to p-nitrophenyl phosphate confirmed the suspicion that alkaline phosphatase activity was present principally in the perichondrium. In view of the strong association between alkaline phosphatase and vertebrate cartilage mineralization it is proposed that extremely low levels of this enzyme may contribute to the failure of invertebrate cartilage to be replaced by bone.     

Factors affecting the availability and use of hemodialysis facilities

This article describes factors related to the geographic distribution of hemodialysis facilities and the relationship between availability and use. Such facilities tend to be concentrated in the same types of areas as other medical resources, and the number of medical specialists in an area is related to the rate of treatment for renal diseases. The proportion of treatment stations in an area owned by for-profit organizations is not related to the total treatment rate, but the market share of for-profit facilities is positively related to in-center treatment and negatively related to home treatment.     

Treatment variables in relation to oocyte maturation: Lessons from a clinical micromanipulation-assisted in vitro fertilization program

Objective: In an effort to understand the mechanism underlying the improved pregnancy rate observed in IVF cycles when gonadotropin-releasing hormone analogues (GnRH-a) are applied, we investigated a possible relationship between treatment variables and oocyte-nuclear maturity. Design: Nuclear maturity was retrospectively assessed in cumulus-free, denuded oocytes, obtained from women undergoing micromanipulation-assisted IVF treatment following controlled ovarian hyperstimulation with GnRH-a and menotropins. Setting: The setting was the infertility and IVF unit of a tertiary academic medical center. Participants: Two hundred twenty-one patients underwent 435 treatment cycles. Main Outcome Measure: This was the proportion of germinal vesicle-intact immature (GVII) oocytes. Results: One hundred fifty-four of the 3520 oocytes studied (4.4%) were in the GVII stage. These oocytes were found in 66 of the treatment cycles (15.2%) and in 54 of the patients (24.4%). Cycles in which GVII oocytes were detected did not differ from those in which all the aspirated oocytes were mature in the following respects: patient age, type and duration of infertility, controlled ovarian hyperstimulation protocol and time of ovum pickup. However, the GVII group was characterized by a significantly higher peak estradiol level, as well as a higher number of mature follicles visualized sonographically (diameter, >14 mm) and oocytes retrieved. Conclusions: Comparing the present findings with previously published data, it appears that the inclusion of GnRH-a in the stimulation regimen is associated with a lower proportion of immature oocytes. A higher occurrence of oocyte-nuclear immaturity is apparently associated with a significantly better ovarian response to stimulation. The high incidence of immature oocytes observed in patients with normospermic partners and low fertilization rates in previous cycles may suggest that the fertilization failure in some of these cases is due to oocyte, rather than sperm, dysfunction.     

Tacrolimus for the prevention and treatment of rejection of solid organ transplants

Since its introduction to the antirejection armamentarium in 1994, tacrolimus has become the workhorse of transplant professionals for avoidance of solid organ transplant rejection. Not only does tacrolimus have potent immunosuppressive qualities that prevent rejection, but dosing is straight forward and it is generally well tolerated. However, in the long term, conditions such as calcineurin inhibitor nephrotoxicity can become a problem. A discussion of the compound, the pharmacokinetics, history, and current approved uses for tacrolimus is described. Indeed, tacrolimus is the most important drug for preventing transplant rejection. However, the increased appreciation for significant side effects, particularly in the long term, has led to building interest in new agents with different mechanisms of action and different metabolism.     

Dosage effects of X and Y chromosomes on language and social functioning in children with supernumerary sex chromosome aneuploidies: implications for idiopathic language impairment and autism spectrum disorders

Background: Supernumerary sex chromosome aneuploidies (X/Y‐aneuploidies), the presence of extra X and/or Y chromosomes, are associated with heightened rates of language impairments and social difficulties. However, no single study has examined different language domains and social functioning in the same sample of children with tri‐, tetra‐, and pentasomy X/Y‐aneuploidy. The current research sought to fill this gap in the literature and to examine dosage effects of X and Y chromosomes on language and social functioning. Methods: Participants included 110 youth with X/Y‐aneuploidies (32 female) and 52 with typical development (25 female) matched on age (mean ～12 years; range 4–22) and maternal education. Participants completed the Wechsler intelligence scales, and parents completed the Children’s Communication Checklist‐2 and the Social Responsiveness Scale to assess language skills and autistic traits, respectively. Results: Both supernumerary X and Y chromosomes were related to depressed structural and pragmatic language skills and increased autistic traits. The addition of a Y chromosome had a disproportionately greater impact on pragmatic language; the addition of one or more X chromosomes had a disproportionately greater impact on structural language. Conclusions: Given that we link extra X chromosomes with structural language impairments and an extra Y chromosome with pragmatic language impairments, X/Y‐aneuploidies may provide clues to genetic mechanisms contributing to idiopathic language impairment and autism spectrum disorders.