Biomedical subjects

B Lewis

Publications and source records attributed to B Lewis.

At least 91 records · Page 5Linked to original sources

PubMed1994

Treponematosis and Lyme borreliosis connections: explanation for Tchefuncte disease syndromes?

A convergence of evidence from macroscopic, radiographic and histologic examination indicates that treponemal infection was present in the 16ST1 Tchefuncte Indian burial population, dated 500 B.C. to 300 A.D. Pattern and nature of lesions suggests that chronic infection induced by variants of the spirochete Treponema pallidum, causing endemic syphilis and/or yaws, resulted in third-stage osseous response. It is suggested that Tchefuncte Indians acquired partial immunity to treponemal infection by exposure to a variant of the related spirochete, Borrelia burgdorferi, the causative agent of Lyme disease. Partial immunity would help explain the relatively mild expression of the treponemal disease process in the 16ST1 skeletal population and the apparent absence of venereal syphilis. Presence of the Borrelia burgdorferi spirochete might be linked to a single incidence of juvenile rheumatoid arthritis.

Arthritis, Juvenile↗

PubMed1994

Ergot induced peripheral vascular insufficiency, non-interventional treatment.

We report a case of ergotamine tartrate induced severe vasospasm in the renal arteries and the arteries of the lower extremities. Classic features seen on peripheral angiography make the diagnosis. Anticoagulation, thrombolysis, vasodilation, steroids, and prostaglandin inhibitors all have been successfully used to treat symptomatic ergot induced arterial vasospasm. Although balloon angioplasty of ergot induced vasospasm has been described in case reports, ergot vasospasm is a self limited and medically treatable condition that does not require peripheral mechanical intervention, unless the immediate threat of necrosis and gangrene exists.

Adult↗

PubMed1994

Recovery of neuromuscular function after atracurium and pancuronium maintenance of pancuronium block.

The study was undertaken to determine whether a neuromuscular blockade induced with pancuronium but maintained with atracurium was associated with a shorter time to complete recovery after administration of neostigmine than if the blockade was maintained with pancuronium alone. Anaesthesia consisted of thiopentone, N2O/O2/enflurane and fentanyl, and the neuromuscular blockade, induced by pancuronium 0.1 mg.kg-1 was monitored by the force of contraction of adductor pollicis during major abdominal surgery lasting 2-5 hr. In 24 patients--Group 1--atracurium 0.07 mg.kg-1 was repeated when the first twitch of the train-of-four (TOF) returned to 25% of control (T1/TC 25). In 28 patients--Group 2--pancuronium 0.015 mg.kg-1 was given at similar recovery of T1/TC. At the end of surgery, neostigmine 0.07 mg.kg-1 and glycopyrolate 0.015 mg.kg-1 were given to reverse the residual neuromuscular blockade which was indicated by a T1/TC of less than 25% in all patients. The time from injection of the reversal drugs to a TOF ratio of 70% was similar in both groups (Group 1, 11.6 +/- 7.6 min; Group 2, 10.1 +/- 6 min; P = NS), but the recovery index was smaller in Group 2 (Group 1, 4 +/- 2.6 min; Group 2, 2.61 +/- 1.2 min; P < 0.05). Furthermore, there was no difference between groups in the duration of action of each redose. The study showed that when compared with pancuronium, equipotent doses of atracurium were not associated with (a) a shorter time to complete recovery from a neuromuscular blockade induced with pancuronium or (b) a shorter duration of action.

Adult↗

PubMed1994

Regional fat distribution by dual-energy X-ray absorptiometry: comparison with anthropometry and application in a clinical trial of growth hormone and exercise.

1. The purpose of this study was to determine the suitability of ratios derived from dual-energy X-ray absorptiometry (DXA) whole body scans to assess regional fat distribution in older men and women by comparing them with the waist-to-hip ratio (WHR) and to evaluate their clinical utility by applying them in a clinical trial involving resistance exercise and recombinant human growth hormone. 2. Sixty-four healthy older adults (39 women and 25 men), aged 65-82 years, served as subjects. The ratios of trunk fat-to-total fat, trunk fat-to-body weight, trunk fat-to-limb fat and trunk fat % were determined by DXA. WHR was assessed on the same day, as was the ratio of subscapular/triceps skinfolds in men. Cardiovascular disease risk factors, functional capacity and serum lipids were also assessed. 3. A moderate relationship (r = 0.36-0.54) between the WHR- and DXA-derived ratios were observed for both men and women. Both DXA and WHR showed similar associations with cardiovascular disease risk factors. However, in men, all DXA ratios were able to detect subtle changes in regional fat distribution resulting from daily administration of recombinant human growth hormone in conjunction with resistance exercise for 10 weeks, whereas the WHR or subscapular/triceps ratios did not. 4. This suggests that DXA-derived ratios may be more sensitive than conventional anthropometric methods in the assessment and categorization of body fat distribution.

Absorptiometry, Photon↗

PubMed1994

The comparative analgesic efficacy of transcutaneous electrical nerve stimulation and a non-steroidal anti-inflammatory drug for painful osteoarthritis.

Thirty-six non-hospitalized subjects with chronic pain from OA of the knee participated in an evaluation of transcutaneous electrical nerve stimulation (TENS) and naproxen, an NSAID. All pre-experiment treatment was withdrawn. Each subject experienced in some order three 3-week treatment phases: NSAID plus placebo TENS; TENS plus placebo drug; and double placebo. A broad range of pain measures was used, including daily diary ratings, and four-times-per-day ratings entered into a small electronic data logger (the PIPER) worn by the subject. A substantial placebo response occurred across all conditions, which may have masked treatment differences. Broad comparisons across subjects, combining the four main measures of pain, found no significant differences among the three experimental treatments. Analysis of diary and PIPER data for individuals suggested that, in a small minority of subjects, the NSAID plus placebo TENS combination may be more effective than double placebo. The PIPER ratings seemed to tap aspects of the pain experience different from those captured by conventional measures, suggesting the value of very frequent pain assessments, such as those entered by a subject into the PIPER, in the study of chronic pain.

Adult↗

PubMed1994

Quantifying the effect of hand preference on upper limb bone mineral and soft tissue composition in young and elderly women by dual-energy X-ray absorptiometry.

The purpose of this study was to quantify the effect that hand preference has on upper limb bone mineral and soft tissue composition in healthy young and elderly women. Bone mineral content (BMC) in grams, bone mineral density (BMD) in g cm-2, fat-free soft tissue (FFST) in grams, fat tissue (g), and percent fat were determined by dual-energy X-ray absorptiometry (DXA) for dominant and non-dominant upper limbs as well as total body fat (%) in 25 young (26.6 +/- 4.3 years, mean +/- SD) and 35 elderly women (68.4 +/- 2.9 years). For both groups, the dominant upper limb had a greater BMC (P < 0.001), BMD (young, P < 0.001; elderly, P < 0.05), and FFST mass (P < 0.001), and a lower percent fat (young, P < 0.01; elderly, P < 0.05) than the non-dominant limb; however, there was no difference between limbs for total fat mass. BMC, BMD, and FFST in the dominant limb of young women were 7.1%, 1.8%, and 5.1% greater than the non-dominant limb, while for older women the differences were 5.3%, 1.0%, and 4.2%. Relative fat of the dominant limb was 3.0% and 1.3% less than the non-dominant limb for young and older women, respectively. Age did not affect the percent bone mineral or soft tissue difference. A higher bone mineral and FFST mass in the dominant limb is expected due to the greater activity demands placed upon these tissues. However, a larger bone and FFST mass increases the total mass of the dominant limb, resulting in a dilution of the fat tissue mass and hence a reduced fat percent for the limb. This study indicates that hand preference affects the tissue composition of the upper limb in both young and elderly women, resulting in an increased bone mineral and FFST mass with no change in absolute fat mass. Hand preference should be taken into account when upper limb bone mineral and/or soft tissue composition is assessed.

Absorptiometry, Photon↗

PubMed1994

Psychotherapy, neuroscience, and philosophy of mind.

Neuroscience is conceptually founded on a philosophy of mind known as identity theory. This theory claims that mental phenomena are reducible to the physical organ of the brain. But identity theory, and consequentially neuroscience, is unable to address essential human features of intentionality, consciousness, and autonomy, i.e., free will. Intentionally is the quality of having content or "aboutness," consciousness is quality of self-awareness, and autonomy is the ability to make undetermined choices. These essential human features make up our common sense and our psychodynamic understanding of ourselves. Without these features we would have to change our entire way of seeing ourselves and our dynamic psychotherapy would be impossible. We need intentionality in psychotherapy because it is only through the content of our patients' thoughts and feelings that we can help them derive meaning; we need consciousness because it is primarily through introspection that we get access to our patients' inner world; and we need autonomy because unless our patients have the option of doing things differently there is no point to the therapeutic endeavor. Consequently, psychiatry cannot rely solely on neuroscience as its basic science without creating a conception of people devoid of essential human features and without eviscerating its psychotherapeutic capacity.

Awareness↗

PubMed1994

Isolated glycerol kinase deficiency in a neonate.

Glycerol kinase deficiency occurs either as a relatively benign isolated enzyme deficiency, or as part of a syndrome resulting from a microdeletion in the p21 region of the X chromosome associated with congenital adrenal hypoplasia and/or Duchenne muscular dystrophy. Developmental delay is a consistent feature of the microdeletion syndrome but not of the isolated enzyme defect. We report a case of isolated glycerol kinase deficiency in a neonate presenting with hypotonia, apnea, mild developmental delay, and glyceroluria, without evidence of adrenal insufficiency or myopathy. A mild communicating hydrocephalus was noted on magnetic resonance imaging brain scan. It is important, therefore, to exclude glyceroluria in infants being investigated for apnea and hypotonia.

Apnea↗

PubMed1994

Radioimmunoassay of hair for determination of cocaine, heroin, and marijuana exposure: comparison with self-report.

Radioimmunoassay of hair (RIAH) was compared with self-report for cocaine, heroin, and marijuana in two populations: 109 persons entering residential drug user treatment and 86 at follow-up posttreatment. Among treatment entrants, 89% of 87 RIAH cocaine-positives and 96% of 45 RIAH heroin-positives were confirmed by self-report. However, among those followed-up posttreatment, only 51% of 43 RIAH cocaine-positives and 67% of 18 RIAH heroin-positives were so confirmed. Whereas 95% of 104 self-reports of cocaine use in the combined population were confirmed by RIAH, only 69% of 80 self-reports of heroin use were. Self-report and RIAH for marijuana were weakly associated.

Adolescent↗

PubMed1994

Atropine and ephedrine adsorption to syringe plastic.

The purpose of this study was to compare daily changes in the concentration of atropine or ephedrine sulfate solutions that had been stored up to 4 days in plastic or glass syringes. Sets of three plastic and one glass syringe were used for each drug; the glass syringes acted as controls. Each set of syringes was labeled as day 0, 1, 2, 3, or 4. Syringes with medication were laid horizontally, had needles attached, and were stored in the dark at an ambient temperature. Each day, the assigned set of syringes was analyzed by high-performance liquid chromatography. Results showed that the change in the ephedrine sulfate concentration in the plastic syringes from day 0 to day 4 was less than 1.4%. Atropine sulfate decreased 52% over 4 days, with the largest single drop occurring during the first 24 hours. It can be concluded that the two brands of ephedrine sulfate stored up to 4 days at ambient temperature in the brand of syringe used do not significantly decrease in concentration. However, this was not the case with the brand of atropine sulfate studied. The practice of storing atropine sulfate in plastic syringes should be discouraged, because of the possibility of loss of potency due to medication adsorption to syringe plastic.

Adsorption↗

PubMed1994

Metabolic determinants of the course of coronary artery disease in men.

We examined associations between metabolic variables and changes in coronary artery disease (CAD) in the St. Thomas' Atherosclerosis Regression Study (STARS). The course of CAD over 3 years was measured continually by quantitative coronary angiography, i.e., as the per patient change in the mean absolute width of coronary segments (delta MAWS). The decrease in MAWS (progression of CAD) was significantly correlated with in-trial plasma concentrations of cholesterol (P = 0.002), low-density lipoprotein (LDL) cholesterol (P = 0.001), apolipoprotein B (apoB) (P = 0.008), and lipoprotein(a) [Lp(a)] (P = 0.004); no significant associations were found with high-density lipoprotein (HDL) cholesterol, apoA-I, vitamin E, thyroid hormones, fibrinogen, von Willebrand factor, or post-load plasma glucose and insulin concentrations. By multiple regression analysis, LDL cholesterol was the best predictor of delta MAWS, the adjusted model explaining 22% of the variance (P = 0.04). Thus, in men with symptomatic CAD the most important metabolic predictor of change in CAD is plasma LDL cholesterol, there being no advantage in measuring other variables, in particular, apoB or Lp(a).

Adult↗

PubMed1993

Interaction between transcription factors Sp1 and YY1.

A basal level of transcription is usually observed when all but a small region of DNA has been deleted from a eukaryotic gene promoter. These promoter elements, which are necessary and sufficient for specific transcription initiation, are referred to as minimal or core promoter elements. One element that is commonly present in a core promoter is the initiator. It has been demonstrated that the presence of Sp1 binding sites can greatly enhance the level of transcription initiation at initiator elements. A binding site for the YY1 transcription factor, located at the initiation site of the adeno-associated virus P5 promoter, functions as an initiator element; a synergistic enhancement of its activity is observed in vitro when upstream Sp1 binding sites are present. Here we report that this synergistic activation probably occurs through protein-protein interactions.

Animals↗

PubMed1993

Hypo- and hyperresponse of serum cholesterol level and low density lipoprotein production and degradation to dietary cholesterol in man.

Serum cholesterol in man rises when cholesterol intake increases, but the extent of the elevation varies between subjects. Part of the variation between subjects is spurious and not reproducible; it is caused by random diet-independent fluctuations of serum lipid levels. Part is due to consistent metabolic differences between subjects. We have earlier found that responsiveness was associated with higher initial total and HDL cholesterol, lower habitual cholesterol consumption, and lower body mass index, and unrelated to gender, age, or apo E phenotype. We have now investigated the metabolic basis of variability by measuring turnover rates of low density lipoprotein (LDL) apolipoprotein B (apo B) on a low-cholesterol diet (140 mg/day) and a high-cholesterol diet (900 mg/day) in 8 volunteers with well-defined differences in the responsiveness of their serum cholesterol to diet. Autologous 125I-LDL was injected on day 23 of each diet period. Its fractional catabolic rate (FCR) was estimated from the ratio of 125I in urine over that in plasma, seven days after injection. FCR (mean +/- SD) increased from 0.24 +/- 0.02 pools/day on the low- to 0.31 +/- 0.20 on the high-cholesterol diet. LDL-apo B concentration rose from 49 +/- 13 to 63 +/- 12 mg/dl, and LDL-apo B production rate, calculated as FCR x concentration/body weight, from 4.8 +/- 1.2 to 8.0 +/- 1.4 mg/kg/day. The individual rise in production rate was significantly correlated with the rise in the serum concentration of LDL-apo B (r = 0.90) or LDL-cholesterol (r = 0.75), and also with the rise in total serum cholesterol measured in these same subjects in similar experiments 3-4 years earlier (r = 0.74). Degradation of LDL by freshly isolated blood mononuclear cells and by mononuclear cells incubated for 72 h in lipoprotein-deficient medium (derepressed cells) was measured on both diets in these and in additional volunteers. The rate of degradation (mean +/- SD) of standard human LDL by fresh cells was 336 +/- 166 ng LDL protein/mg cell protein per 8 h on the low-cholesterol diet, and decreased by 147 +/- 180 ng/mg per 8 h or 44% on the high-cholesterol diet (n = 23, p < 0.01). The catabolic activity of derepressed cells obtained when subjects were on the low-cholesterol diet was negatively related to the LDL cholesterol response (r = -0.57, n = 18, p < 0.05), and to the total cholesterol response in earlier experiments (r = -0.45, n = 18, p < 0.10).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1993

Identification of a GBR12935 homolog, LR1111, which is over 4,000-fold selective for the dopamine transporter, relative to serotonin and norepinephrine transporters.

The di-substituted piperazines, GBR12909 (1-[2-[bis(4-fluorophenyl)-methoxy]ethyl]-4-[3- phenylpropyl]piperazine) and GBR12935 (1-[2-(diphenyl-methoxy)-ethyl]-4-(3-phenylpropyl)piperazine), are potent and selective (20-to 100-fold) inhibitors of [3H]dopamine reuptake, relative to [3H]5-HT and [3H]norepinephrine uptake. The GBR12935 analog, 1-(2-(diphenylmethoxy)ethyl)-4-(3-phenylpropyl)homopiperazine (LR1111), was synthesized as part of a systematic structure-activity study of analogs of GBR12935 and GBR12909. LR1111 differs from GBR12935 by the addition of a methylene group into the piperazine ring to yield a compound with a seven-member homopiperazine ring. The IC50 values for LR1111 at the dopamine, norepinephrine, and serotonin transporters were 7.2 nM, 34,072 nM, and greater than 20,000 nM, respectively, whereas the IC50 values of GBR12935 were 3.7 nM, 289 nM, and 1261 nM for these same transporters. This demonstrates that the addition of a single methylene group in the piperazine ring results in a compound with similar affinity but significantly higher selectivity for the dopamine transporter. LR1111 increased motoric activity in rats after intravenous administration. These indicate that LR1111 is a potent and highly selective inhibitor of the dopamine transporter.

Animals↗

PubMed1993

Independent associations between plasma lipoprotein subfraction levels and the course of coronary artery disease in the St. Thomas' Atherosclerosis Regression Study (STARS).

Associations between plasma lipoprotein subfractions and changes in coronary artery diseases (CAD) were examined in 74 men who completed the St. Thomas' Atherosclerosis Regression Study (STARS). Plasma lipoproteins were isolated by stepwise, preparative ultracentrifugation at repeated intervals during the 38-month trial. Paired coronary angiograms were quantitatively analyzed by a computerized method. In univariate linear regression analysis, changes in mean absolute width (delta MAWS) and minimum absolute with (delta MinAWS) of coronary segments were significantly correlated with in-trial concentrations of cholesterol in intermediate-density lipoprotein ([IDL] d = 1.006 to 1.019 kg/L), low-density lipoprotein ([LDL2] d = 1.019 to 1.040 kg/L; LDL3, d = 1.040 to 1.063 kg/L), and high-density lipoprotein ([HDL3] d = 1.125 to 1.210 kg/L) subfractions; no significant associations were found with other lipoproteins. IDL, LDL3, and HDL3 cholesterol were then selected for multiple linear regression analysis because these variables were not co-correlated and because they attained a significance of P less than or equal to .1 in univariate regression. In this analysis, only LDL3 cholesterol level was a significant negative predictor (P < .05) of both delta MAWS and delta MinAWS; a positive association between delta MinAWS and HDL3 cholesterol level just failed to reach conventional statistical significance (P = .066). Correlations between changes in coronary luminal dimensions and LDL3 cholesterol level were independent of age, smoking, weight, and blood pressure. Most patients showing regression of coronary atherosclerosis had an LDL3 cholesterol level of less than 1.8 mmol/L. The findings suggest that LDL3 is the plasma lipoprotein subfraction that exerts the single most powerful effect on the course of CAD in middle-aged men with hypercholesterolemia.

Analysis of Variance↗

PubMed1993

Prediction of early symptomatic recurrence after intestinal resection in Crohn's disease.

OBJECTIVE: This study was performed to identify clinical criteria that may help recognize patients with Crohn's disease who are at high risk for early symptomatic postoperative recurrence. SUMMARY BACKGROUND DATA: Currently, no reliable criteria are available to help recognize patients who are prone to experience early symptomatic recurrence. METHODS: One hundred sixty-four patients undergoing intestinal resection for Crohn's disease at the Mount Sinai Hospital between 1976 and 1989 were studied prospectively. Patients with symptomatic recurrent disease within 36 months were defined as having an early recurrence. RESULTS: Multivariate analysis revealed that the number of anastomoses was the most important prognostic indicator (p = 0.001), followed by inflammation at the resection margins (p < 0.05). Patients requiring an ileostomy had a significantly lower early recurrence rate than those having single or multiple anastomoses. There was no significant correlation between inflammation at the margins and early recurrence in patients requiring an ileostomy (n = 38), or a single anastomosis (n = 98). When the margins were examined in the 28 patients with 2 or more anastomoses, 10 of 11 patients (91%) with inflammation at either margin experienced early recurrence. Patients having multiple anastomoses with normal margins had the same recurrence rate as patients with single anastomosis (42%). CONCLUSIONS: Patients with extensive Crohn's disease requiring multiple resections with anastomosis, especially when microscopic inflammation is present at the margins, are at very high risk for symptomatic early recurrence. Ileostomy seems to be associated with a significantly lower early recurrence potential than anastomosis. Further study is needed to determine whether avoidance of multiple anastomosis and adjuvant medical treatment can alter the course of the disease after intestinal resection in patients at high risk for early symptomatic recurrence.

Adolescent↗

PubMed1993

Low bone mineral density at axial and appendicular sites in amenorrheic athletes.

Amenorrheic athletes have low axial bone-mineral density (BMD, g.cm-2). We compared 12 amenorrheic and 9 eumenorrheic women athletes to determine whether athletes with amenorrhea have lower BMD in other skeletal regions, including weight-bearing lower limbs. BMD was measured by dual energy x-ray and single photon absorptiometry. Both groups had similar age, body mass, and exercise quantity. Women with amenorrhea missed 86.3 +/- 58.3 menstrual periods since menarche. BMD was lower in the amenorrheic vs eumenorrheic subjects for the lumbar spine (0.928 +/- 0.056 vs 1.050 +/- 0.110, P < 0.005), whole body (1.032 +/- 0.05 vs 1.09 +/- 0.06, P < 0.05), most regions of the whole body (P < 0.05-0.001), all areas of the proximal femur (P < 0.005), and at the femoral mid-shaft (1.333 +/- 0.109 vs 1.491 +/- 0.088, P < 0.005). No significant differences were detected at the mid-radius and tibial shaft. The best predictors of BMD were years of regular menstruation for lumbar spine; and years of amenorrhea for hip, femoral mid-shaft, and whole body. We conclude that low BMD in athletes with amenorrhea is not limited to the axial skeleton but is also present in other regions including appendicular weight-bearing bones.

Absorptiometry, Photon↗

PubMed1993

Obscure gastrointestinal bleeding.

I want to convey the notion that enteroscopy has opened many doors, and continues to open up more doors, in understanding and diagnosing diseases of the small intestine. The true nature of small-bowel angiodysplasia is still unanswered. It seems unlikely that the lesions in the small bowel are similar to the lesions that Scott Boley talks about in the right colon. I doubt that the intermittent obstruction to venous outflow, theorized in the colon, is the pathophysiologic change in the small intestine. Those studies, trying to look for the changes that Boley described, need to be done. We are trying to better characterize angiodysplasia of the small intestine, understanding where they occur, with how many lesions, and whether they are associated with any other illnesses. We are looking at the association of small-bowel vascular lesions with lesions in the stomach and colon. Enteroscopy will in the future, we hope, answer these questions. Enteroscopy, especially push enteroscopy, can help us with the treatment of angiodysplasias. We are now evaluating new instruments that reach not just two feet beyond the ligament of Treitz, but the entire jejunum, reaching 6 feet beyond the ligament of Treitz (16). Enteroscopy facilitates clinical research, can be used in patient care, and guides treatment.

Aged↗