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R Pine

Publications and source records attributed to R Pine.

46 records · Page 3Linked to original sources
PubMed1985

Construction and characterization of a library of metallothionein coding sequence mutants.

New possibilities for experimental investigation of the metallothionein system at the DNA, RNA, and protein levels are now available via a library of metallothionein coding sequence mutants. Appropriate treatment in vitro with sodium bisulfite of the sense or antisense DNA strands in M13 phage vectors and propagation in Escherichia coli BD1528 (ung-) produced two unique collections in the library containing either C to T or G to A transition mutations in the codons at low and high frequencies. The strategy for mutagenesis takes advantage of degeneracy in the genetic code so that no cysteine codons are replaced in the CT mutants while all are subject to change in the GA collection. Two hundred and sixty-four clones from the library have been sequenced and G to A transitions affecting each of the 20 cysteine codons in metallothionein have been detected. Other mutations in codons for amino acids proposed to be important for metallothionein function have also been identified.

Amino Acid Sequence↗
PubMed1984

Control of postcarotid endarterectomy hypotension with baroreceptor blockade.

The reported incidence of hypotension after carotid reconstruction ranges from 21 to 50 percent. To evaluate baroreceptor dysfunction, 283 carotid reconstructions were studied. During 181 consecutive reconstructions, a transcutaneous Teflon catheter was positioned intraoperatively at the carotid bifurcation for postoperative injection of lidocaine as necessary. Of 283 reconstructions, 210 (74 percent) were not followed by hypotension. In the remaining 73 (26.5 percent), hypotension (systolic blood pressure less than 100 mm Hg) was seen. In 14 of the 73 cases of hypotension, vasoactive drugs, atropine, or a fluid bolus was administered with variable responses. In 27 of the 73, no treatment was instituted. In the remaining cases of hypotension, treatment consisted of 1 to 2 ml of lidocaine administered through the catheter. A prompt increase in systolic blood pressure from 93 to 139 mm Hg (means) within 30 minutes of treatment occurred in 29 of the 32 cases (91 percent). These data currently support routine catheter placement.

Blood Pressure↗
PubMed1981

Cadmium-induced accumulation of metallothionein messenger RNA in rat liver.

Multiple injections of nontoxic levels of cadmium to a rat result in much higher level of metallothionein (MT) production in the liver than does the single injection. In order to understand the underlying mechanisms we have quantitated and compared the metallothionein-specific messenger RNA contents in the livers following the two induction regimens. Cell-free translation assays coupled with specific immunoprecipitation of MT revealed that MT-mRNA activity in livers of animals multiply injected with Cd is 7- to 10-fold higher than that in livers 4 h after a single Cd-induction. By oligo(dT)-cellulose chromatography, sucrose density gradient centrifugation, and methylmercuric hydroxide-agarose gel electrophoresis this mRNA has been enriched approximately 100-fold from the total RNA. The size of the mRNA is about 400 nucleotides. Hybridization assays with a complementary DNA probe synthesized against the enriched MT-mRNA showed a 4-fold difference in the level of MT-mRNA between the two induction regimens in agreement with the results obtained by the cell-free translation assays. The possible mechanisms for these observations in consideration of the short lived nature of MT-mRNA are discussed.

Animals↗
PubMed1980

Haptic-visual shape matching by mentally retarded children: exploratory activity and complexity effects.

The accuracy of nonretarded persons in shape matching within and across vision and touch improves with development, and matching by eye is usually better than is matching by hand. The pattern is less clear with mentally retarded children, however. In the present experiment we compared haptic and visual matching of retarded and nonretarded children at different developmental levels, while systematically observing variables known to have developmentally linked effects on task accuracy, including stimulus complexity and haptic exploratory search style. The results showed that accuracy depended on both stimulus complexity, modality, and mental age, regardless of whether or not children were retarded. The selection of haptic search styles also depended on these factors but, in addition, was influenced by intellectual status of the children.

Adolescent↗
PubMedDate not supplied

Indications, outcomes, and provider volumes for carotid endarterectomy.

CONTEXT: While trials have demonstrated that carotid endarterectomy is superior to best medical therapy, most recently among asymptomatic patients, uses and outcomes of the procedure in more representative settings have not been established. OBJECTIVES: To profile the use and outcomes of carotid endarterectomy in a representative sample of Ohio's Medicare beneficiaries and to examine the relationships between provider-specific procedural volumes and patient outcomes. DESIGN: Retrospective cohort using Medicare Provider Analysis and Review files supplemented by detailed reviews of medical records on a random sample of patients. SETTING: Ohio hospitals performing carotid endarterectomy. PATIENTS: A random sample of 678 charts of the 4120 non-health maintenance organization Medicare beneficiaries who underwent carotid endarterectomy between July 1, 1993, and June 30, 1994. MAIN OUTCOME MEASURES: Nonfatal stroke or death within 30 days of surgery. RESULTS: The reviewed patients were similar to all eligible patients in sociodemographic characteristics and 30-day mortality rates. Among the 678 patients, indications for surgery were asymptomatic carotid stenosis in 167 (24.6%), transient ischemic attack in 294 (43.4%), completed stroke in 62 (9.1%), and nonspecific symptoms in 155 (22.9%). Thirty-two patients (4.7%) died or suffered nonfatal strokes by 30 days postoperatively. In univariate analyses, rates varied by hospital volume (P=.004) but not surgeons' volume (P=.47), although power to detect this difference was limited. Patients at higher- and lower-volume hospitals had similar indications and distributions of comorbidities. In analyses controlling for indications, comorbid conditions, and surgeon's volume, being operated on in a higher-volume hospital conferred a 71% reduction in risk for 30-day stroke or death (odds ratio, 0.29; 95% confidence interval, 0.12-0.69; P=.006). CONCLUSIONS: Almost half (47.5%) of the carotid endarterectomies among Ohio's Medicare population are performed on persons who are asymptomatic or who have nonspecific symptoms. These results highlight the importance of identifying patients and providers having the most favorable outcome profiles. The higher rate of adverse outcomes observed in lower-volume hospitals deserves further investigation, as it does not appear to be due to differences in patient selection.

Aged↗