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Biomedical subjects

S M Lewis

Publications and source records attributed to S M Lewis.

At least 127 records · Page 7Linked to original sources
PubMed1989

A study of the reliability of clinical palpation of the spleen.

Clinical palpation of the spleen was assessed by reference to a radionuclide scan method for measuring spleen volume in vivo from V = 9.88A - 534, where V = volume (cm3) and A = posterior scan area (cm2) (Zhang & Lewis 1987). The position of the spleen tip in relation to the costal margin correlated well with clinical palpability when the spleen was clearly enlarged, but when the spleen tip was just below the costal margin it was not always palpable. In some cases a normal-sized spleen was palpable, whereas a non-palpable spleen was not always normal sized. As the scanning method gives an accurate measurement of spleen size it is especially useful in lesser degrees of enlargement when reliable information on the splenomegaly may help to elucidate a diagnosis and problems of management.

Adolescent↗
PubMed1989

Radioisotope studies in monitoring of Gaucher's disease and its treatment.

Radioisotope studies (blood volume, spleen function, and ferrokinetics) were performed in seven patients with chronic (type 1) Gaucher's disease. Interestingly, the 52Fe scans and spleen histology demonstrated extramedullary haemopoiesis in the liver and spleen. Radioisotope measurements (red cell volume, plasma volume, red cell pool, damaged cell clearance, spleen blood flow, 59Fe clearance, red cell utilization and 52Fe scans) provide methods for accurate measurement of the bone marrow and spleen function, thereby enabling prediction of the most suitable time for splenectomy, in the treatment of patients with Gaucher's disease.

Gaucher Disease↗
PubMed1989

The splenomegaly of myeloproliferative disorders: effects on blood volume and red blood count.

By means of a scintigraphic method for estimation of spleen size, the relationship was studied between spleen size and anaemia, total blood volume and red cell volume in patients with myeloproliferative disorders. There was significant correlation between spleen size and Hb, RBC and PCV in myelofibrosis. The size of the enlarged spleen did not, however, correlate with the degree of anaemia in the leukaemias. There was positive correlation between spleen size and red cell volume in these conditions. It was not possible to evaluate the severity of polycythaemia from spleen size and the degree of enlargement of the spleen does not appear to be a reliable parameter for staging and deciding on treatment in patients with PPP.

Anemia↗
PubMed1989

Development of polycythaemia vera in a patient with myelofibrosis.

In March 1981, a 53-year-old man presented with itching and was diagnosed as having myelofibrosis. There was gradual enlargement of the spleen over the following 5 yr. His spleen had to be removed in February 1986 because of physical discomfort. 3 months post-splenectomy he became polycythaemic. Bone marrow examination was consistent with severe myelofibrosis. It was possible to demonstrate erythropoietin-independent BFU-E from peripheral blood, and ferrokinetic studies showed that erythropoiesis was localised to the liver with little bone marrow activity. Thus, despite severe marrow fibrosis, liver erythropoiesis was now polycythaemic, suggesting the coexistence of myelofibrosis and polycythaemia vera.

Bone Marrow↗
PubMed1989

The splenomegaly of myeloproliferative and lymphoproliferative disorders: splenic cellularity and vascularity.

Employing radionuclide scanning, the volume of the spleen, its red cell pool and plasma pool have been measured in vivo, and the relative proportions of cellularity and vascularity of the spleen have been calculated in 51 patients with myeloproliferative and lymphoproliferative disorders. In primary proliferative polycythaemia (polycythaemia vera), the increase of spleen size was attributed mainly to the increase of splenic vascularity; in myelofibrosis and in hairy cell leukaemia, the increase of spleen size was associated with increase in both splenic vascularity and cellularity, whilst in CGL and CLL the increase was attributed more to cellularity than to vascularity.

Female↗
PubMed1989

Primary health screening by haemoglobinometry in a tropical community.

The usefulness of a recently developed portable haemoglobinometer in primary health care was assessed in a survey of anaemia carried out in an isolated Indian community living in the jungles of northern Peru. This haemoglobinometer requires only one drop of blood to be added to a disposable cuvette without predilution; other advantages and limitations of the method are described. A high incidence of anaemia was found in men, women and children. Although intestinal parasite infections, including hookworm, were prevalent, there was no direct relationship with the anaemia. These observations indicated the need for a more extensive epidemiological study to identify the etiological factors. Considering the importance of reliable haemoglobin measurements for providing baseline data, the study demonstrated the value of this portable, simple-to-operate haemoglobinometer for use in geographically remote areas with little or no laboratory facilities. An important advantage was that locally recruited workers were able to measure the haemoglobin easily and correctly after a brief training session.

Adult↗
PubMed1989

Effects of pulsed electromagnetic fields on Steinberg ratings of femoral head osteonecrosis.

Between 1979 and 1985, 95 patients with femoral head osteonecrosis met the protocol for treatment of 118 hips with selected pulsed electromagnetic fields (PEMFs). Etiologies included trauma (17), alcohol (9), steroid use (46), sickle cell disease (2), and idiopathy (44). The average age was 38 years, and the average follow-up period since the onset of symptoms was 5.3 years. PEMF treatment had been instituted an average of 4.1 years earlier. By the Steinberg quantitative staging method of roentgenographic analysis, none of the 15 hips in Stages 0-III showed progression, and grading improved in nine of 15. Eighteen of 79 hips (23%) with Stage IV lesions progressed and none improved. In the Stage V category, one of 21 hips (5%) worsened and none improved. Three Stage VI lesions were unchanged. The overall rate of quantified progression for the 118 hips, 87% of which had collapse present when entering the program, was 16%. This value represents a reversal of the percentage of progression reported recently by other investigators using conservative and selected surgical methods. PEMF patients also have experienced long-term improvements in symptoms and signs, together with a reduction in the need for early joint arthroplasty.

Adult↗
PubMed1988

Novel strand exchanges in V(D)J recombination.

We describe novel products of V(D)J recombination in which signal sequences become joined to coding elements, in contrast to the standard reaction whose products are junctions of two signal sequences or two coding elements. In this variant reaction, the recombination machinery evidently recognizes signal sequences and introduces strand breaks at the normal positions, but then connects the elements in unusual combinations. The lack of fixed directionality indicates that recombination sites are not uniquely aligned when strand exchange occurs. The discovery of these variant junctions suggests a model for the evolution of the antigen receptor loci.

Animals↗
PubMed1988

Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy.

To determine noninvasively the etiology of left ventricular (LV) dysfunction, 22 patients with a diagnosis of cardiomyopathy determined via cardiac catheterization and 5 normal control subjects underwent radionuclide ventriculography and intravenous dipyridamole-thallium-201 perfusion scanning. Both ischemically and nonischemically induced LV dysfunction had comparable global LV ejection fractions (24 +/- 6 vs 23 +/- 8%, respectively) and extent of segmental wall motion abnormalities. Right ventricular ejection fraction was significantly better in the group with an ischemic etiology of LV dysfunction (41 +/- 26 vs 13 +/- 10%, p less than 0.005) but significant group overlap was present. However, computer-assisted analysis of dipyridamole-thallium-201 myocardial perfusion scanning demonstrated more homogeneous myocardial perfusion in idiopathic cardiomyopathy (mean perfusion defect 25 +/- 11 vs 6 +/- 6%, p less than 0.001) and successfully predicted the correct etiology of LV dysfunction in 20 of 22 (91%) patients.

Cardiomyopathies↗
PubMed1988

Acute myocardial infarction in diabetes mellitus and significance of congestive heart failure as a prognostic factor.

Diabetes mellitus has been associated with high mortality rates in patients with acute myocardial infarction (AMI). To better define prognosis in this population, the clinical course of 183 diabetics with AMI was studied. In-hospital mortality for all patients was 28% (52 of 183 patients). Mortality was significantly higher in patients with prior AMI than in patients without prior AMI (41 vs 18%, p less than 0.01) and was significantly higher in women than in men (37 vs 19%, p less than 0.01). The 2-fold increase in mortality among diabetic women was observed both in patients with and without prior AMI. The excess mortality among diabetic women was attributable to their increased risk for severe congestive heart failure (CHF) and cardiogenic shock. Death due to CHF occurred in 22% of all diabetic women with AMI compared with 6% of the diabetic men (p less than 0.01). Death resulting from complications other than CHF was similar for both sexes. There were no male-female differences in the history of prior AMI, systemic hypertension, obesity, nephropathy, frequency of Q-wave AMI, anterior AMI or peak creatine kinase levels to account for the high risk for CHF in diabetic women. It is therefore concluded that diabetic women with AMI are at increased risk for death due to CHF, and that this risk is not readily attributable to known conditions associated with CHF.

Adult↗
PubMed1988

Mean platelet volume and size distribution and their sensitivity to agonists in patients with coronary artery disease and congestive heart failure.

Mean platelet volume was related to platelet count in patients with myocardial infarction (n = 55) and patients with congestive heart failure (n = 9). 18 patients with acute myocardial infarction were tested at admission and 4-7 days later, together with 13 patients with chronic stable angina and 10 patients with chest pain which was not related to coronary artery disease. In citrated blood a relative reduced frequency of large platelets (greater than 13 fl) occurred in patients with acute myocardial infarction at admission but was not seen during recovery or in patients with chronic stable angina. This suggests consumption of large platelets at time of thrombus formation. No relation was found between plasma catecholamine levels and mean platelet volumes. Effects of serotonine, adrenaline and CGP 28392, a calcium agonist, on platelet volume distributions were determined. Sensitivity of platelets to adrenaline was increased in patients with acute myocardial infarction on admission and reduced 4-7 days later, while in patients with congestive heart failure reactivity to both serotonine and adrenaline were reduced. This indicates a fast down-regulation during the early recovery phase of myocardial infarction and chronically in congestive heart failure.

Adult↗
PubMed1988

Effects of alkaline hydrogen peroxide treatment on in vitro degradation of cellulosic substrates by mixed ruminal microorganisms and Bacteroides succinogenes S85.

The effects of sodium hydroxide (NaOH) and alkaline hydrogen peroxide (AHP) treatments on wheat straw (WS) and various cellulosic substrates were determined by measuring susceptibility to degradation by mixed ruminal organisms or Bacteroides succinogenes S85. In vitro incubations were used to measure differences in fermentation resulting from each successive step in the AHP treatment process. In vitro incubations through 48 or 108 h were conducted to measure these differences. The AHP treatment of WS increased (P less than 0.05) dry matter, neutral detergent fiber, and acid detergent fiber degradation over control WS when these substrates were incubated with mixed ruminal microorganisms or B. succinogenes S85. Fermentations containing AHP-treated WS had greater (P less than 0.05) microbial purine (RNA) and volatile fatty acid concentrations by 12 h compared with those containing untreated or NaOH-treated WS. Xylose in AHP-treated WS was utilized more extensively (P less than 0.05) by 12 h compared with the xylose of untreated or NaOH-treated WS. Treatment with AHP removed 23% of the alkali-labile phenolic compounds from WS. When substrates with high levels of crystalline cellulose (raw cotton fiber, Solka floc, and Sigmacell-50) were treated with NaOH or AHP and incubated for 108 h with B. succinogenes S85, extent of acid detergent fiber degradation of cotton fiber and Sigmacell-50 was similar to that of their respective controls. Sodium hydroxide and AHP treatments were effective in increasing acid detergent fiber degradation of the Solka floc which contained, on average, 3.3 and 4.8 percentage units more acid detergent lignin and hemicellulose, respectively, than cotton fiber and Sigmacell-50.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Bolus technique for assessing distribution of inspired gas during tidal breathing.

The washout of an insoluble tracer from the lung may be represented by a model with two ventilatory compartments representing poorly and better-ventilated regions. Using boli of a second insoluble gas delivered at a given point during inspirations of a multibreath washout test, the proportions of labeled inspired ventilation reaching the poorly and well-ventilated regions may be determined by analyzing the kinetics of the exhaled tracer. We studied eight normal subjects breathing through large-bore solenoid valves controlled to maintain tidal volume at 600 or 900 ml. Boli consisting of 15 ml of 80% He-20% O2 were delivered over 75 ms; this labeled approximately 125 ml of inspired gas. Boli were delivered after 50 ml had been inspired to mark early inspiration and after 300 ml had been inspired to mark midinspiration. Using 900-ml tidal breaths, late inspiration was marked by boli delivered at 600 ml. Subjects were studied in the seated and the supine positions. In both positions, significantly more of the early breath went to the poorly ventilated compartment. Several possible physiological mechanisms, singly or in combination, could account for these observations, but differences in dead space path length are most likely involved.

Adult↗
PubMed1988

The WHO international external quality assessment scheme for haematology.

Quality assurance is essential in laboratory medicine; an important component is external quality assessment in order to ensure that reliable performance is achieved by all laboratories and that between-laboratory comparability is maintained. In a number of countries there are national external quality assessment schemes. WHO has established a programme aimed at encouraging the organization of similar schemes in all countries. Towards this goal an international external quality assessment scheme has been established for each of the specialities of haematology, clinical chemistry, microbiology and parasitology.This paper describes the organization of the international scheme for haematology. There are now 62 laboratories taking part in 49 countries. The functioning of the scheme, the participants' response, and the extent to which the scheme has improved the standard of practice in their laboratories are described.

Hematology↗