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M Kelly

Publications and source records attributed to M Kelly.

At least 199 records · Page 11Linked to original sources
PubMed1995

Development of delta-opioid receptor subtypes and the regulatory role of weaning: radioligand binding, autoradiography and in situ hybridization studies.

Evidence from behavioral studies suggests that the process of weaning activates the development of a delta-opioid receptor subtype. We now report the influence of weaning on the development of delta receptors in the central nervous system assessed by membrane homogenate binding and autoradiography with selective delta radioligands and by in situ hybridization using a cRNA probe for the delta receptor. Binding was carried out by using [3H][D-Ala2]deltorphin I (DELT I), [3H]IIe5,6-deltorphin II (IIe5,6-DELT II) and [3H]naltrindole (NTI). [3H]IIe5,6-DELT II and [3H]NTI labeled an equivalent number of sites in brain and spinal cord from both weaned and nonweaned 25-day-old rats. The number of sites labeled by [3H]DELT I was similar in nonweaned rats but significantly higher in the brain and cord from weaned animals. Furthermore, the ontogenetic profile of these three ligands was distinct. Quantitative autoradiography showed identical levels of [3H]IIe5,6-DELT II binding in all brain regions in weaned and nonweaned rats. In contrast, levels of [3H]DELT I binding were significantly higher in weaned rats and this difference was localized to the deep layers of the frontal-parietal cortex and to the pontine nucleus. In situ hybridization experiments showed no differences in delta-opioid receptor mRNA density between weaned and nonweaned groups in the regions in which binding differences were observed. Weaning stimulates the development of a subpopulation of delta receptors recognized by [3H]DELT I but not by [3H]IIe5,6-DELT II or NTI. This effect is localized to specific brain regions and does not appear to reflect increased synthesis of mRNA coding for the delta receptor.

Animals↗
PubMed1995

Safety and efficacy of increasing wintertime vitamin D and calcium intake by milk fortification.

We studied the safety and efficacy of milk fortified with vitamin D3 and calcium. Over the winter, we conducted a double-blind, placebo-controlled trial of fortified milk (12 micrograms vitamin D3 and 1525 mg calcium per litre) compared to unfortified milk (0.3 micrograms vitamin D3 and 1270 mg calcium per litre) in 102 adults (aged 17-54 years). Serum 25-hydroxyvitamin D [25(OH)D], ionized calcium, and creatinine were measured at baseline and after intervention. Fortification reduced the seasonal decline in serum 25(OH)D concentrations by > 50%. In the fortified group, serum 25(OH)D decreased by 15 nmol/l from 77 +/- 35 nmol/l to 62 +/- 26 nmol/l (p < 0.001). In the control group, serum 25(OH)D fell by 31 nmol/l from 85 +/- 38 nmol/l to 54 +/- 25 nmol/l (p < 0.001). We suggest that milk enriched with vitamin D be provided in high-latitude European countries to diminish the wintertime fall in serum 25(OH)D.

Adolescent↗
PubMed1994

Mutagenesis of a gene encoding a cytochrome o-like terminal oxidase of Azotobacter vinelandii: a cytochrome o mutant is aero-tolerant during nitrogen fixation.

The amino acid sequence obtained by translating the nucleotide sequence of a 0.55 kb fragment, amplified from Azotobacter vinelandii chromosomal DNA by PCR, was 57% identical to part of the Escherichia coli cyoB gene, encoding subunit I of the cytochrome bo-type quinol oxidase. This fragment was mutated in vitro by insertion of a kanamycin-resistance cassette and introduced into the chromosome of A. vinelandii by homologous recombination. The mutant contained no spectrally detectable cytochrome o. However, in the stationary phase of growth, the level of the alternative oxidase (cytochrome bd) was 11-fold higher than in the wild-type strain. Respiration of the mutant was insensitive to chlorpromazine, an inhibitor thought to act specifically on cytochrome o. Cytochrome o-deficient mutants fixed nitrogen in air, clearly distinguishing the role of this oxidase from that of cytochrome bd, which is required for respiratory protection of oxygen-labile nitrogenase.

Amino Acid Sequence↗
PubMed1994

Purification and properties of porcine liver ornithine transcarbamylase.

Ornithine transcarbamylase (OTCase) has been purified from porcine liver by a simple four-step procedure that included chromatography on an affinity column to which the transition-state analogue, delta-N-phosphonacetyl-L-ornithine (PALO), was covalently bound. The procedures employed yielded an enzyme which was purified some 260-fold and was judged to be homogeneous by nondenaturing- and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Apparent homogeneity of the enzyme was confirmed by N-terminal sequence analysis. The molecular weight of the porcine enzyme was determined by Sephadex gel exclusion chromatography and sedimentation equilibrium. An approximate molecular weight of 107,000 was calculated by both procedures. The single band obtained by SDS-PAGE indicated a subunit molecular weight of 36,800 +/- 700; hence, the enzyme is a trimer of identical subunits. The sedimentation coefficient of the native enzyme was determined to be 6.47. At pH 8.0, the Km values for the substrates are 0.41 and 1.3 mM for ornithine and carbamyl phosphate, respectively. PALO is a competitive inhibitor and has a Ki of 0.13 microM, which suggests that it binds with about 10,000 times greater affinity than carbamyl phosphate. Amino acid analysis performed on acid hydrolyzed enzyme yielded 323 amino acids per monomer. Performic acid oxidation of the enzyme, followed by acid hydrolysis and amino acid analysis, showed three cysteine residues per subunit. A partial specific volume of 0.725 cc/g was calculated from the amino acid composition. Reaction of purified porcine OTCase with phenylglyoxal, an arginine-specific reagent, results in complete loss of catalytic activity. The decrease in enzymatic activity correlates with the modification of 1 mol of arginine per mole of OTCase monomer. In the presence of 20 mM carbamyl phosphate, 93% of the activity is retained during a 1-h reaction time. Other substrates and substrate combinations offer less protection.

Amino Acid Sequence↗
PubMed1994

Release of ATP from cholinergic synaptic vesicles during freeze-thaw cycling.

Cholinergic synaptic vesicles were isolated from Torpedo californica and subjected to repeated freeze/thraw (F/T) cycles. Both vesicular (trapped) and released (free) ATP were measured after each cycle. It was found that a constant percentage of vesicular content was released during each F/T cycle. In solutions low in Ca2+ and Mg2+ and high in sucrose, 25% of the ATP is released by each F/T cycle. When synaptic vesicles are resuspended in Tornedo Ringer's (which contains less sucrose, higher Ca2+ and urea), 35-40% of the trapped ATP is released during each F/T cycle. These data contradict the hypothesis that F/T does not disrupt synaptic vesicle membranes (although F/T does disrupt cell membranes and synaptosomes). This nonrupture hypothesis was assumed by C. Solsona, C. Saltó, and A. Ymbern (1991, Biochim. Biophys. Acta 1095, 57-62) to calculate cytosolic ATP as 40% of total ATP. Our results indicate that cytosolic ATP is 10-15%. These results may also explain some of the discrepancies in reported values for cytosolic acetylcholine (ACh). Values of 35-50% were obtained by previous workers using the nonrupture hypothesis, and values of 8-22% in experiments that did not depend on the nonrupture hypothesis. Our results refute the nonrupture hypothesis and thus support a lower value for cytosolic ACh.

Adenosine Triphosphatases↗
PubMed1994

Magnesium and arrhythmias after coronary artery bypass surgery.

Arrhythmias are very common after cardiac surgery and are multifactorial. Magnesium is receiving increased consideration in the management of supraventricular and ventricular arrhythmias. This study was designed to evaluate the role of magnesium in preventing arrhythmias in hypokalemic (K < 3.5 mEq/L) and normokalemic (K > 3.5 mEq/L) patients with normal renal and ventricular function after coronary artery bypass grafting (CABG). One hundred forty patients ranging from 32 to 71 years of age who were scheduled for CABG were studied. They were divided into four groups: group I (control) received no magnesium; group II received 10 mg/kg of magnesium sulfate intravenously before cardiopulmonary bypass (CPB); group III received 10 mg/kg of magnesium soon after CPB; group IV received 10 mg/kg of magnesium before and after CPB. Serum potassium and catecholamine levels, as well as serum and urine magnesium levels, were measured and the incidence and type of arrhythmias were determined. There was a statistically significant difference in the occurrence of arrhythmias between the groups studied. The incidence of arrhythmias was highest in groups I and II and lowest in group IV (12 patients in group I, 14 in group II, 5 in group III; and 1 in group IV). Magnesium levels were higher in group IV than any other group studied after completion of surgery. There was no difference in serum and urine magnesium levels between the hypokalemic and normokalemic patients within each group. Serum magnesium returned to normal in all patients after 48 hours. Therefore, it appears that administration of magnesium during and after cardiac surgery reduces the incidence of arrhythmias in hypokalemic and normokalemic patients.

Adult↗
PubMed1994

Is paracervical block anesthesia for oocyte retrieval effective?

OBJECTIVE: To quantitate pain relief associated with paracervical local anesthesia during transvaginal ultrasound-guided collection. DESIGN: The study was a prospective, randomized, double-blinded, placebo-controlled, and no treatment-controlled investigation. Pain scores for vaginal pain associated with entry into the cul-de-sac and global assessment for the entire procedure were generated separately by patient and physician. Variables evaluated include duration of procedure, patient weight and age, total number of vaginal and ovarian "follicular" punctures, number of oocytes retrieved, and amount of IV medication. SETTING: A private IVF-ET program. PATIENTS: Women in an IVF-ET program who volunteered to join the study (n = 101). INTERVENTIONS: Local anesthesia as a paracervical block compared with placebo or no injection during transvaginal oocyte retrieval, with all patients receiving IV sedation. RESULTS: Both vaginal and global pain scores, whether patient or physician assessed were lower for paracervical block than placebo. Agreements between physician and patient assessments of pain scores were close. Duration of the procedure was correlated with pain score. In general, a placebo effect on pain perception compared with no injection was not seen. CONCLUSION: Paracervical local anesthesia compared with placebo injection was associated with lower pain scores for both vaginal puncture and global assessment of the oocyte retrieval process but was not significantly better than no injection for global evaluation.

Adult↗
PubMed1994

Intraobserver and Interobserver Variability in Scoring Laparoscopic Diagnosis of Pelvic Adhesions

Videotapes of laparoscopic procedures are used for patient and physician education, independent consultation, and even in the courtroom as evidence. Validation of the interpretation of the videotape with respect to intraobserver and interobserver difference has been scarcely studied. As part of the protocol of a prospective, double-blind, placebo study a standardized adhesion scoring system was developed by the investigators. After laparoscopic adhesiolysis and instillation of either an active or placebo agent designed to prevent reformation of adhesions, a second look laparoscopy was performed between 6 and 10 weeks later to allow for a second adhesion score. Five reproductive surgeons evaluated via videotape pre and post adhesion scores in which 11 patients (22 procedures) were operated by one member of the group. Three months after the initial scoring of the videotapes each tape was reevaluated in order to measure intraobserver variability. Intraobserver and interobserver variability was assessed for adhesion extent as well as adhesion severity scores and also included consideration of the differences between the first and second procedures using sophisticated statistical methods. Intraobserver variability for adhesion severity was 12% versus 19% for interobserver variability. The replicate (intraobserver) variability for adhesion extent was 15.4% and interobserver variability was 21.2%. Two of the five observers consistently scored pathology as more severe than two others. The surgeon scored differences between the two procedures as greater than the other observers. Nevertheless, the variability was not so great as to preclude videotape evaluation of pathology in multicentric trials, or to allow for independent consultation of laparoscopic procedures via videotape.

Journal Article↗
PubMed1994

A sustained outbreak of Clostridium difficile in a general hospital: persistence of a toxigenic clone in four units.

OBJECTIVE: To evaluate the endemicity and epidemiology of toxigenic Clostridium difficile in a sustained outbreak of antibiotic-associated diarrhea. SETTING: University-affiliated, 465-bed tertiary care teaching hospital with adjacent cancer clinic in Hamilton, Ontario. DESIGN: From August 8, 1991, through August 31, 1993, a total of 187 cases were investigated for epidemiologic analysis of toxigenic C difficile from stool cultures, to identify the endemic clone(s). To assess the nature of contamination, cultures of inanimate surfaces in the patient environment from the four most affected units (medical teaching, nonteaching medical, hematologic oncology, and the intensive care unit) were processed for C difficile. The 229 clinical strains and 24 environmental strains isolated were typed by numerical analysis of SDS-PAGE protein patterns. RESULTS: A majority (81%) of cases in the epidemiologic analysis were associated with a toxigenic electrophoretic (EP) type 1 C difficile that was identical to the strain first isolated from an index case that occurred 18 months before the start of this study. Culture and typing of the C difficile strains from the inanimate surfaces in the four most affected units showed that the patient environment was contaminated with the toxigenic EP type 1 organism. Six other strains that occurred infrequently among cases also were found in the environment. CONCLUSIONS: A single predominant toxigenic clone has been implicated in a sustained outbreak of antibiotic-associated diarrhea that affected elderly patients. The "endemic" clone transmitted for the 25-month study period was linked to an index case shedding a toxigenic EP type 1 strain that occurred 21 months prior to the initial outbreak on the medical teaching unit. The patient environment in the affected units was found to be contaminated with the same clone, possibly due to shedding of organisms by fecally incontinent symptomatic patients. The extrinsic factors contributing to the endemic transmission of this one clone still are not well understood.

Bacterial Typing Techniques↗
PubMed1994

Northern Sudan in 1991: food crisis and the international relief response.

By the end of 1991, less than half the amount of relief food requested for North Sudan at the beginning of the year had been delivered. Despite ample evidence of social and economic stress and high rates of child malnutrition, many donors felt that relief needs had been exaggerated, and were unwilling to accept that relief assistance was urgently needed. The feeble response of the main food aid donors is explained initially by the politics of relief in 1990/91, which seriously delayed the launch of the relief operation. These problems were compounded by an oversimplified understanding of famine among some sections of the relief community, and by the orientation of the international relief system to crisis indicators. Toward the end of 1991, donors argued that despite the shortfall in relief assistance there had been no deaths from starvation, and therefore local people had 'coped' better than expected. This paper challenges that view by arguing that excess deaths did occur, but went unnoticed and unremarked. Local people's 'coping strategies', which supposedly 'saved the day', actually had very negative and sometimes fatal consequences.

Child, Preschool↗
PubMed1994

Mutations of Ki-ras and p53 genes in colorectal cancer and their prognostic significance.

The series of genetic changes leading to malignancy in colorectal cancer is well reported. This includes mutational activation of the proto-oncogene Ki-ras and mutation/deletion of the p53 tumour suppressor gene. The frequency of these mutations was investigated in a panel of 52 colorectal cancer patients using a combination of immunocytochemistry and non-radioactive, digoxigenin-labelled in situ hybridisation. Sixty two per cent (32 of 52) of the study population were positive for p53 overexpression and 36% (19 of 52) positive for Ki-ras mutation. Twenty seven per cent (14 of 52) of the patients expressed both mutations. Mutation of either the p53 or the Ki-ras gene did not correlate with Dukes's stage, tumour differentiation or 5 year survival rate of the patients. Most of the rectal carcinoma specimens (11 of 15) showed p53 over-expression but the significance of this was not supported statistically. Thus detection of molecular changes is becoming more amenable to incorporation into routine histological carcinoma assessment because of the advent of non-radioactive labelling in in situ hybridisation and antibodies suitable for paraffin wax embedded specimens. The significance of these mutations in disease prognosis, however, remains questionable.

Colonic Neoplasms↗
PubMed1994

Expression of components of the RAS during prolonged blockade at different levels in primates.

To assess the effects of inhibition of the renin-angiotensin system at different levels on plasma concentrations of components of the system and on renin and angiotensinogen gene expression, marmosets on a low-sodium diet were treated for 1 wk by continuous intraperitoneal infusion with either the renin inhibitor CGP-29287, the ACE inhibitor benazeprilat, the angiotensin II antagonist valsartan, the renin inhibitory monoclonal antibody R-3-36-16, or vehicle. Plasma total immunoreactive renin increased (14- to 20-fold) after all three modes of interference. Plasma angiotensinogen was significantly reduced in the benazeprilat- and valsartan-treated marmosets but not in the CGP-29287-treated animals. Plasma concentration of angiotensin II was significantly decreased in the benazeprilat-, CGP-29287-, and R-3-36-16-treated marmosets and was increased in the valsartan-treated marmosets. Kidney renin mRNA level increased 8- to 15-fold in all groups. Hepatic angiotensinogen mRNA level increased with CGP-29287 treatment but decreased with the other treatments. Kidney angiotensinogen mRNA level was not affected by any treatment. Different modes of inhibition of the renin-angiotensin system have different effects on plasma components of the system and liver angiotensinogen expression.

Angiotensin II↗