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Biomedical subjects

D McCarthy

Publications and source records attributed to D McCarthy.

179 records · Page 10Linked to original sources
PubMed1971

Regional lung function in patients with hepatic cirrhosis.

The lung volume at which the dependent lung zones begin to trap gas as a result of airway closure (i.e., the "closing volume") was measured with (133)Xe in 10 seated patients with hepatic cirrhosis. In all of them the closing volume was increased above normal, and in eight it was greater than the functional residual capacity, indicating the presence of airway closure and gas trapping during resting tidal volume breathing. Direct measurements made with (133)Xe in five cirrhotic patients (a) confirmed the presence of increased gas trapping in the lower lung zones both at residual volume and at functional residual capacity, and (b) indicated that in liver cirrhosis the ventilation-perfusion ratio of the dependent lung zones may be very low, primarily as a result of decreased ventilation due to airway closure. It is concluded that in hepatic cirrhosis, gas trapping in the dependent lung zones may be an important cause of impaired gas exchange within the lungs. It is suggested that the premature airway closure observed in this disease may be due to mechanical compression of small airways by dilated blood vessels and/or interstitial pulmonary edema.

Adolescent↗
PubMedDate not supplied

Vitamin D intake and status in Irish elderly women and adolescent girls.

AIM: To assess vitamin D status during summer and winter in Irish girls and elderly women, and to estimate vitamin D intake in these two age-groups. METHODS: Ambulatory free-living, elderly Irish women (aged 70-76 years; n = 43) and girls (aged 11-13 years; n = 17) were recruited. Fasting serums were collected during August/ September 2002 and February/March 2003 and analysed for 25 (OH) D by HPLC. RESULTS: Mean daily intakes of vitamin D were 4.6 microg and 2.1 microg in elderly women and girls, respectively. Serum 25 (OH) D was significantly lower (P<0.001) during winter than summer in both age-groups. Eight (20%) and one (during late summer) and sixteen (37.2%) and eight (47%) (during late winter) of the elderly women and girls, respectively, had inadequate vitamin D status (serum 25 (OH) D <40 nmol/l). CONCLUSION: Inadequate vitamin D status during winter time is quite common in elderly women and adolescent girls in Ireland.

Adolescent↗
PubMedDate not supplied

Comparative evaluation of four different infusion rates of ropivacaine (2 mg/mL) for epidural labor analgesia.

BACKGROUND AND OBJECTIVES: Previous studies have reported comparable efficacy for ropivacaine and bupivacaine when used for labor analgesia at concentrations of 2.5 mg/mL. In this multicenter study, we assessed ropivacaine at the commercially available concentration of 2 mg/mL (0.2%) for labor pain management. METHODS: After Institutional Review Board approval and informed consent, 128 women at term were randomly assigned to receive ropivacaine at one of the four infusion rates via a lumbar epidural catheter. Analgesia was initiated with a 5-mL test dose, followed by injections of 5-15 mL of 2 mg/mL ropivacaine. The continuous infusion was then started at 4, 6, 8, or 10 rmL/hour. Rescue analgesia was provided with 5-mL "top-up" injections as necessary to provide maternal comfort. Pain relief was assessed by using a visual analog pain scale (VAPS) and motor block was assessed by using a modified Bromage scale. RESULTS: All infusion regimens effectively decreased VAPS, and most patients in all groups had minimal or no motor block at the end of the first stage of labor. Mean total number of the top-up injections required per patient were 3, 2, 1.5, and 1.4, respectively, in the 4, 6, 8, and 10-mL/hour groups (P < .05, 4 mL/hour vs. all other groups). Despite receiving more total bolus dosages, the 4-mL/hour group had less motor block in the lower extremities (P < .05). Apgar scores and neurological adaptive capacity scores were similar for all groups. CONCLUSIONS: The 2 mg/mL of ropivacaine produces satisfactory labor analgesia at epidural infusion rates of 4, 6, 8, and 10 mL/hour, provided supplemental bolus dosages are available. Clinically, a rate of 6 mL/hour may be the lowest effective rate that provides the best combination of pain relief, motor block, and rebolusing, although rates of 8 and 10 mL/hour produced similar results.

Adult↗
PubMedDate not supplied

Cotranslational folding of nascent proteins on Escherichia coli ribosomes.

Evidence is presented for cotranslational folding of rhodanese or ricin during its synthesis on Escherichia coli ribosomes. During transcription-translation, full-length but enzymatically inactive polypeptides accumulated as peptidyl-tRNA on the ribosomes. These polypeptides were activated and released by subsequent incubation with the bacterial chaperones and with release factor (RF-2). Coumarin was incorporated cotranslationally at the N-terminus of the nascent protein from fluorophore-S-Ac-Met-tRNAf. Changes in fluorescence indicated that DnaJ bound to the nascent proteins and to a fluorescently labeled synthetic peptide corresponding to the N-terminal 17 amino acids of bovine rhodanese. This peptide also bound to 70S ribosomes or 50S subunits but not to 30S subunits. It inhibited activation and RF-2-dependent release of the full-length ribosome-bound rhodanese. A deletion mutant of rhodanese lacking the N-terminal 23 amino acids was not accumulated on the ribosome but was synthesized very efficiently. However, the protein that was formed was enzymatically inactive. DnaJ did not bind to this deletion mutant on ribosomes. We conclude that the chaperone-mediated reactions facilitate binding of the N-terminal sequence of nascent proteins to a specific site on 50S ribosomal subunits where it blocks release. The ribosome-bound protein undergoes chaperone-mediated reactions that are required for folding into an enzymatically active conformation.

Amino Acid Sequence↗
PubMedDate not supplied

Insulin-like growth factor-I enhances immune response in dexamethasone-treated or surgically stressed rats maintained with total parenteral nutrition.

BACKGROUND: New evidence suggests that insulin-like growth factor-I (IGF-I) is an important regulator of immune response. Our objective was to determine the effects of IGF-I on immune response during total parenteral nutrition (TPN) using two stress models. METHODS: Male, Sprague-Dawley rats (230 to 250 g) were given TPN with or without coinfusion of recombinant human IGF-I (800 micrograms/d for 6 days) and subjected to either dexamethasone, a synthetic glucocorticoid, or surgical stress, in the form of a midline abdominal incision. In the dexamethasone model, immune response was assessed by total cellularity of the thymus and spleen, in vitro assays of lymphocyte proliferation, and interleukin 6 (IL-6) production, and concentrations of IL-6 and tumor necrosis factor alpha (TNF-alpha) in serum. In the surgical model, flow cytometry was used to identify and quantify splenic populations of T and B lymphocytes and macrophages. RESULTS: In rats immunosuppressed by dexamethasone, IGF-I infusion increased mitogen-induced proliferation of thymocytes, but did not alter cellularity in the thymus; enhanced proliferation and IL-6 production in peripheral blood mononuclear cells following treatment with concanavalin A or lipopolysaccharide; and reduced the serum concentration of IL-6, but not TNF-alpha. In surgically stressed rats, IGF-I infusion restored the splenic populations of immature and mature B lymphocytes, which were decreased by TPN. CONCLUSIONS: our data demonstrate that IGF-1 enhances immune response during TPN in rats.

Animals↗