Search PubMed⌕ Search

Biomedical subjects

N Smith

Publications and source records attributed to N Smith.

At least 181 records · Page 10Linked to original sources
PubMed1988

A prototype device for nonimmersion shock wave lithotripsy using ultrasonography for calculus localization.

Extracorporeal shock wave lithotripsy has revolutionized the clinical treatment of renal calculi. A device was constructed with a spark gap for shock wave generation and a water-filled ellipsoidal reflector to focus the shock wave energy. A membrane coupled the device to the pig and an ultrasonic transducer was used for stone visualization. Initial in vitro experiments and in vivo studies using dwarf pigs demonstrated fragmentation of calculi.

Animals↗
PubMed1988

Effect of ischemia on calcium-dependent fluorescence transients in rabbit hearts containing indo 1. Correlation with monophasic action potentials and contraction.

The effects of acute global ischemia on cytosolic calcium transients were studied in perfused rabbit hearts loaded with the fluorescent calcium indicator indo 1. Indo 1-loaded hearts were illuminated at 360 nm, and fluorescence was recorded simultaneously at 400 and 550 nm from the epicardial surface of the left ventricle. The F400/F550 ratio was calculated by an analog circuit, which allowed cancellation of optical motion artifact. Resulting calcium transients demonstrated a rapid upstroke and slow decay similar to those recorded in isolated ventricular myocytes. Global ischemia rapidly suppressed contraction, but it produced a concurrent increase in the systolic and diastolic levels of the calcium transients, together with an increase in the duration of the peak. The effects of ischemia were reversed by reperfusion, inhibited by verapamil, and mimicked by perfusion of nonischemic hearts with acidified (CO2-rich) solution. In addition to elevation of the calcium transients, ischemia caused a pattern of intracellular calcium alternans that was discernible after 2-3 minutes. The pattern of alternans was stable at a given epicardial site, but it could be out of phase at different sites. Similar nonuniformities were observed in contraction strength and in the duration of monophasic action potentials recorded immediately adjacent to the fiber-optic probe. Abnormalities in intracellular calcium may be a causal factor in the loss of electrical and mechanical synchrony in the acutely ischemic heart.

Action Potentials↗
PubMed1987

ABC of AIDS. Tumours.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Cytosolic calcium transients from the beating mammalian heart.

To elucidate the role of cytosolic calcium, [Ca2+]i, in the physiology of the normal and ischemic heart, we have developed a method for recording [Ca2+]i transients from the epicardial surface of the rabbit ventricle after arterial perfusion with the cell-permeant cytosolic calcium indicator indo-1 AM. Hearts were illuminated at 360 nm, and fluorescence was recorded simultaneously at 400 and 550 nm. The F400/F550 fluorescence ratio was calculated by an analog circuit that allowed cancelation of small movement artifacts that were present at single wavelengths. Clear [Ca2+]i transients were present in the F400/F550 signal and were remarkable for their slow decay. Slow decay of the transients was not due to buffering of [Ca2+]i by indo-1, since there was no associated impairment of contraction or relaxation. The peak amplitude of the [Ca2+]i transients was increased by ouabain, adrenaline, postextrasystolic potentiation, and acetylcholine. The extent to which the transients decayed diminished with shortening of the interbeat interval, but decay of the transients could be further diminished by acetylcholine or caffeine. A major advantage of the intact heart over isolated myocytes is the ability to measure changes in [Ca2+]i during ischemia. Ischemia produced a marked increase in both peak systolic and end-diastolic [Ca2+]i, which was most rapid during the first 30 sec, and approached a plateau value after 90 sec. This increase in [Ca2+]i was associated with a characteristic broadening of the peak of the transient. The increase in [Ca2+]i during ischemia is consistent with a proposed causative role of [Ca2+]i in mediating early electrophysiological abnormalities.

Acetylcholine↗
PubMed1987

Gallbladder surgery in patients over 60: is there an increased risk?

We reviewed the records of 101 patients over the age of 60 who had exploration and cholecystectomy in 1982 at Norfolk General Hospital. There were 52 elective and 49 emergency cases. Women comprised 57.4% of the patients, and almost 50% of the patients were over the age of 70. Forty-nine percent of the cases were emergencies. All but two of the patients had cholecystectomy. The average hospital stay was 12 days for the elective group and 19 days for the urgent group. Complications extended the average hospital stay to 23 days. Although complications developed in 35 patients, only 14 had major complications that were life-threatening and/or extended the hospital stay. Of these, four were in elective cases (7%) and the remainder (21%) were in the urgent group. A major complication more than doubled the average hospital stay to 29 days. There were three deaths (3% of the entire group), all in patients who had emergency exploration, and all in patients over age 70. We advocate earlier elective cholecystectomy for patients with symptomatic cholelithiasis--before patients reach an older age, when associated systemic diseases increase their overall risk should emergency operation be necessary.

Acute Disease↗
PubMed1987

Cost savings through community access to the NSW Poisons Information Centre.

In addition to handling urgent emergency calls for advice about major poisonings, the NSW Poisons Information Centre handles calls from the general community about poisonings of a much more minor nature. Although these poisonings may be perceived by the callers to be significant, the only action required is either reassurance that there is, in fact, no problem or simple treatment that does not require further intervention. The study demonstrates that callers in this category would have sought professional advice elsewhere had the Centre not existed and the subsequent cost effectiveness of the Centre's role in taking these calls.

Community Health Services↗
PubMed1987

The incidence of severe trauma in small rural hospitals.

Trauma is the third leading cause of death in the United States, and yet relatively little is known about its epidemiology, especially in rural areas. A retrospective study was done in five Washington and Idaho communities to determine the incidence of severe trauma seen in small rural hospitals. Records were reviewed for the year 1983 on all trauma patients (565 cases) who were either admitted to or transferred from these hospitals. The study area included five hospitals and 30 physicians, serving a population of 57,600 people over 7,396 square miles. Each patient's injuries were rated according to the Injury Severity Score (ISS), a standardized trauma index. Of the cases reviewed, 3.4 percent of the cases had an ISS greater than or equal to 20, reflecting severe multisystem trauma, 14.7 percent had an ISS of 10 to 19, ie, severe trauma limited to one body system or multisystem trauma of a less-critical nature. There were 30 patients (5.3 percent) with critical head injuries, 24 patients (4.2 percent) with major chest injuries, and 21 patients (3.7 percent) with serious abdominal injuries. The results showed that each individual physician or hospital did not see the severe cases often, but that when they occurred, these types of injuries necessitated an experienced, rapid response on the part of the hospital staff. This finding has significant implications for trauma management in rural communities.

Abdominal Injuries↗
PubMed1986

Screening tests for Sezary cells in cutaneous T-cell lymphomas.

Blood samples from normal individuals (n = 7), from patients with cutaneous T-cell lymphomas (Sezary syndrome = 7; mycosis fungoides = 18) and from patients with chronic benign skin disease (n = 8) were examined for the presence of Sezary cells. The samples were analysed using a Coulter model S Plus IV with a three Cell Population upgrade, and a Becton Dickinson FACS analyser; and the results were compared with those obtained from morphological examination of peripheral blood films. Using the FACS analyser a population of aneuploid cells was only identified in two out of eight patients with confirmed circulating Sezary cells. This was in contrast to the results from the Coulter S Plus IV which detected an abnormality in six out of the eight samples with confirmed circulating Sezary cells. These results indicate that leukocyte volume analysis is a useful, additional screening tool for the identification of Sezary cells.

Flow Cytometry↗
PubMed1986

[Intraepidermal melanocytic proliferation. A practical guide to the classification of ambiguous melanotic skin lesions and of possible precursors of malignant melanomas].

A group of senior Pathologists engaged in review work on international randomized trials for the W.H.O and/or the E.O.R.T.C., propose a new simplified classification of melanocytic lesions with an intra-epidermal component, applicable in routine. This classification attempts to introduce standards to permit morphological identification of a large group of intra-epidermal melanocytic proliferations with three classes of atypia (slight, mild, severe) and group of malignant melanomas especially those without dermal invasion. The new definitions and objective criteria (at cytological and architectural level) of diagnosis are given with examples of equivalence between some established entities and this new universal terminology.

Cell Transformation, Neoplastic↗
PubMed1985

Dermatofibrosarcoma protuberans: a clinicopathological and immunohistochemical study with a review of the literature.

Forty-one cases of dermatofibrosarcoma protuberans are presented. The clinical features and histopathological appearances are described. Immunohistochemical staining of thirteen cases with antisera to lysozyme, alpha 1-antichymotrypsin and S-100 protein has provided no evidence to support either a histiocytic or neuroectodermal origin for these tumours. In reviewing the literature, the histogenetic origin, differential diagnosis and malignant potential of dermatofibrosarcoma protuberans are discussed.

Adolescent↗
PubMed1985

Volvulus of cecum following simple nephrectomy.

We report a case of intestinal obstruction secondary to cecal volvulus following a palliative nephrectomy. Cecal volvulus and other causes of acute abdomen should be considered in postoperative patients who develop adynamic ileus undergoing retroperitoneal surgery.

Aged↗
PubMed1985

Treatment of bleeding esophageal varices by portoazygos disconnection and esophageal transection with the button of Boerema and EEA stapler: ten years' experience.

We present 64 patients with bleeding esophageal varices who have been treated with portoazygos disconnection, devascularization of the esophagogastric junction, and esophageal transection with the button of Boerema (32 patients) and EEA stapler (32 patients). The patients were treated between 1973 and 1983. Their ages ranged from 50 to 70 years. Based on Child's classification, 26 (37.5%) of the patients fell into class A, 35 (54.6%) in class B, and five (7.8%) in class C. These patients were also divided into three subgroups: group I--21 patients (32.8%) underwent emergency operations; group II--40 patients (62.5%) underwent semiemergency operations; and group III--three patients (4.7%) underwent elective operations. The perioperative mortality rate was 10.8%. With the Fischer exact test, we found the combined death rate of Child's classes A and B to be significantly lower than that for class C patients. The duration of follow-up ranged from 6 months to 9 years (average 32.9 months) in the 80% of the patients that we were able to follow. There was a 6.5% incidence of recurrent gastrointestinal bleeding and a 28% incidence of late encephalopathy. The incidence of transitory dysphagia was 40% when the button of Boerema was used as compared with 9% when the EEA stapler was used. The surgical approach presented herein is an attractive alternative to portosystemic decompression for patients in whom hepatic dysfunction is complicated by uncontrolled variceal hemorrhage.

Aged↗