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Biomedical subjects

J Roberts

Publications and source records attributed to J Roberts.

At least 325 records · Page 18Linked to original sources
PubMed1994

Medicaid managed care: can health plans survive on the government's payments?

The Clinton plan's emphasis on market-driven managed competition, coupled with ever-increasing Medicaid costs, has placed the U.S. health care system on the threshold of significant change. By limiting the growth of premiums, the plan will encourage insurers to negotiate managed care contracts with providers. In this article, the authors discuss how individual states, faced with increasing costs and stretched budgets, have attempted to administer Medicaid programs within a managed care system.

Health Care Reform↗
PubMed1994

Correlates of well-being among caregivers of cognitively impaired relatives.

The characteristics and use of respite services of 64 caregivers of severely cognitively impaired clients were correlated with the caregivers' purposes-in-life and burden outcome scores. Caregiver well-being was similar across users of a variety of respite service packages. Correlates of caregiver well-being, in spite of their burdens, were caregiver hardiness and favourable meaning given illness. Both of these cognitive variables exceeded the importance of perceived social support in explaining the variation in caregiver purpose-in-life.

Caregivers↗
PubMed1994

Pharmacological characterization of muscarinic receptors mediating acetylcholine-induced contraction and relaxation in rabbit intrapulmonary arteries.

Rabbit pulmonary arteries exhibit a biphasic response to acetylcholine consisting of an endothelium-dependent contraction in tissues at resting tone and an endothelium-dependent relaxation in vessels with elevated tone. Each response was studied separately by treating the arteries with inhibitors of nitric oxide synthase to block the relaxant response or with inhibitors of cyclooxygenase to inhibit the contractile response. In the present study, experiments in isolated pulmonary arteries were undertaken to characterize the muscarinic receptor subtypes mediating the two separate responses by utilizing subtype-selective antagonists and determining pA2 values of the antagonists through Schild analysis. Both the relaxant and the contractile responses were inhibited most potently by atropine and by the M3-selective antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide. The pA2 values for inhibition of the contractile and relaxant responses were 9.44 and 8.79 for atropine and 8.92 and 9.29 for 4-diphenylacetoxy-N-methylpiperidine methiodide, respectively. The M1-selective antagonist pirenzepine and the M2-selective antagonist (11-([2-[(diethylamino)methyl]-1-piperidinyl]- acetyl)-5, 11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepine-6-one) displayed much lower affinities for the muscarinic receptors mediating these responses. The pA2 values for inhibition of the contractile and relaxant responses were 6.77 and 6.74 for pirenzepine and 6.06 and 5.70 for (11-([2-[(diethylamino)methyl]-1-piperidinyl] acetyl)-5, 11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepine-6-one), respectively.

Acetylcholine↗
PubMed1993

Involvement of multiple factors in the clonal deletion of self-reactive T cells.

Self-tolerance is primarily induced by the elimination of potentially self-reactive T cells during early development of the T cell repertoire. In the mouse, endogenous mouse mammary tumor viruses (MMTV), including minor lymphocyte-stimulating antigens and milk-transmitted exogenous MMTV, have been known to function as self-antigens inducing the clonal deletion of self-reactive T cells in a V beta-specific manner. We investigated the factors involved in the deletion of V beta 17a-bearing T cells. The results indicated that in addition to the previously reported V beta 17a deletion ligand, Mtv-3, there is a nonmilkborne gene product which progressively deletes V beta 17a (and V beta 3)-bearing T cells during aging. This suggests that clonal deletion is mediated by multiple factors and that a clonal deletion element associated with aging may play a significant role in shaping the T cell repertoire.

Aging↗
PubMed1993

Cirrhosis of undefined pathogenesis: absence of evidence for unknown viruses or autoimmune processes.

To examine whether unknown viruses or autoimmune processes contribute to the development of cryptogenic liver disease, we studied 48 patients undergoing liver transplantation who had non-A, non-B cirrhosis; non-blood-borne cirrhosis of unknown etiology; or autoimmune cirrhosis. After the diagnosis of hepatitis C virus infection was established by the presence of viral antibodies or viral RNA, patients were reclassified into three groups: hepatitis C virus infection, autoimmune cirrhosis and cryptogenic cirrhosis. Explant histological appearance, incidence of posttransplant hepatitis and immunological features were compared in the three groups. Thirty-one percent of patients had neither hepatitis C virus infection nor classical autoimmune cirrhosis and were classified as having cryptogenic cirrhosis. Unlike histological appearance in hepatitis C virus infection but similar to that in autoimmune cirrhosis, explant histological appearance of cryptogenic cirrhosis showed inactive cirrhosis with little inflammation. After transplantation, histological hepatitis of the allograft was demonstrated in 44% of patients with hepatitis C infection but in no patient with autoimmune or cryptogenic cirrhosis. The autoimmune score, developed from clinical criteria associated with autoimmune liver disease, was significantly lower in cryptogenic cirrhosis and hepatitis C virus infection than in autoimmune cirrhosis. Autoantibodies--including antinuclear antibodies, smooth muscle antibodies and liver-kidney microsomal antibodies--were not commonly present in serum of patients with cryptogenic cirrhosis, whereas antibodies to soluble liver antigens were found with increased frequency in this entity. We conclude that in many patients with liver disease, no pathogenesis can be identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoimmune Diseases↗
PubMed1993

A community effect in muscle development.

BACKGROUND: Most vertebrate tissues arise by embryonic induction, as a result of which new cell layers are formed. These are subsequently subdivided into discrete groups of homogeneous cell populations, each containing different cell-types with specific gene expression. There is preliminary evidence from previous work that the mesoderm-forming induction in amphibian development may be followed by a further interaction among some of the induced mesoderm cells, and that this could be required for muscle gene activation in uniform cell populations. RESULTS: We have established the existence, time and place of this further cell interaction by transplanting muscle progenitor cells from Xenopus mid-gastrulae into ectoderm sandwiches, and then culturing these constructs until the time of muscle gene activation. We find that cells implanted as reaggregates, but not those implanted as single cells, activate early myogenic genes and later muscle-specific genes. More than 100 cells must be near each other for muscle gene activation. These cells can induce non-muscle mesoderm cells to express muscle genes by emitting a signal that differs from the preceding mesoderm induction signal. Muscle gene activation under these conditions does not require gap junction communication. CONCLUSION: Cells within the muscle progenitor region of a Xenopus embryo need to interact with each other in order to activate muscle genes in homogeneous cell groups. This exemplifies the 'community effect', which may be a widespread developmental mechanism used to increase the homogeneity within, and demarkation between, embryonic tissues.

Journal Article↗
PubMed1993

Combined laparoscopic and endoscopic management of cholelithiasis and choledocholithiasis.

With the advent of laparoscopic cholecystectomy, optimal management of common duct stones remains controversial. Seven hundred six patients underwent laparoscopic cholecystectomy in our institution from January 1990 through January 1992. From this group of patients, 50 were identified as having clinical or radiographic evidence of common duct stones. Thirty-one patients demonstrated preoperative risk factors for common duct stones and underwent preoperative endoscopic retrograde cholangiopancreatography (ERCP). The risk factors included jaundice (19%), pancreatitis (23%), elevated liver function tests (52%), and ultrasound evidence of choledocholithiasis (6%). Preoperative ERCP was performed in 94% of patients. There were two failures due to periampullary diverticula. Common duct stones were identified in 18 patients (62%) and successfully removed by endoscopic sphincterotomy in all of these patients. Nineteen patients were found to have unsuspected common duct stones on intraoperative cholangiography. Eighteen patients (95%) underwent successful ERCP and endoscopic sphincterotomy with stone extraction. Overall, major morbidity was 2% and included one patient who experienced endoscopic sphincteroplasty. The three endoscopic failures were managed by open common duct exploration, laparoscopic duct exploration, and combined laparoscopic and open common duct exploration. We conclude that combined laparoscopic and endoscopic therapy is a viable option for the management of cholelithiasis with choledocholithiasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1993

Metastatic prostate cancer to the optic canal.

PURPOSE: Optic neuropathies represent a common cause of blindness among patients with cancer. The authors present the clinical and imaging findings and discuss the management of optic nerve involvement from metastatic prostate cancer to the optic canal. METHODS: Five patients with advanced metastatic prostate cancer had visual loss. Neuro-ophthalmologic examination and pre- and post-gadolinium orbital and brain magnetic resonance imaging (MRI) were performed. Compressive optic neuropathy secondary to extensive optic canal involvement was demonstrated in all of the patients. Neuropathologic examination was accomplished in two cases. A combination of steroid and focal radiation therapy was used for treatment in four patients. RESULTS: Imaging and neuropathologic findings demonstrated a compressive optic neuropathy secondary to both epidural metastases and to deformity and hypertrophy of the optic canal due to metastatic cancer. Treatment was of benefit in three cases. CONCLUSION: Acute and subacute unilateral or bilateral optic neuropathy in patients with prostate cancer may be the result of optic canal metastases. Magnetic resonance imaging shows a characteristic pattern of bone hypertrophy and deformity with optic nerve compression. Early combination steroid and radiation therapy may induce long-lasting improvement.

Aged↗
PubMed1993

Revisiting physician impact analyses: predicted versus observed hospital resource use.

In order to determine the accuracy of predictions made using Physician Impact Analysis (PIA), a comparison was undertaken of predicted versus actual resource use for 10 new physician specialists at a southern Ontario community hospital. The predictions were done from 1987 to 1989 using methodology recommended by the Ontario Hospital Association (OHA) and available at that time. This included (1) Hospital Medical Records Institute data and (2) a hospital service department survey. A comparison was made between PIA predictions and actual physician resource utilization data gathered in 1991. There was little agreement between the two. The usefulness of PIA rests largely on its ability to generate accurate predictions about a new physician recruit's number of cases and hospital resource use. However, because this research was undertaken in only one community hospital, further evaluation of the PIA process is recommended.

Data Collection↗
PubMed1993

Psychiatric comorbidity in patients with generalized anxiety disorder.

OBJECTIVE: The goal of this study was to test the validity of generalized anxiety disorder as an independent diagnostic entity and to evaluate the prevalence and type of other psychiatric disorders coexisting with generalized anxiety disorder. Although a few published studies have addressed the subject, this study presents data from a larger group of subjects and excludes concurrent major depression as a potential confound. METHOD: The authors studied patients with a primary diagnosis of generalized anxiety disorder assigned after evaluation with the Structured Clinical Interview for DSM-III-R. Patients with a concurrent major depressive episode were excluded. All diagnoses for which the patient met criteria were determined, including lifetime occurrence of major depressive episode and substance use. RESULTS: One hundred nine patients with generalized anxiety disorder were included in the analysis. Twenty-eight (26%) of these patients were not given any other lifetime psychiatric diagnosis. The most prevalent comorbid diagnoses were social phobia (25 [23%] of the patients) and simple phobia (23 [21%] of the patients). Forty-six (42%) of the patients with generalized anxiety disorder had experienced at least one major depressive episode during their lifetime. CONCLUSIONS: These results support previous findings of high rates of psychiatric comorbidity in generalized anxiety disorder and validate the usefulness of generalized anxiety disorder as a separate diagnostic entity.

Adult↗