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Biomedical subjects

K Link

Publications and source records attributed to K Link.

At least 19 recordsLinked to original sources
PubMed1997

Progress report. A randomized multicenter European study comparing adjuvant radiotherapy, 6-mo chemotherapy, and combination therapy vs no-adjuvant treatment in resectable pancreatic cancer (ESPAC-1).

CONCLUSION: The ESPAC-1 trial is the largest study of its kind in pancreatic cancer and should definitively address the question of the role of conventional methods of adjuvant treatment in pancreatic cancer. BACKGROUND: At the joint International Association of Pancreatology and the European Pancreatic Club meeting in Mannheim, Germany (June 12-15, 1996) a satellite meeting of the European Study Group for Pancreatic Cancer (ESPAC) met to discuss the progress of the ESPAC-1 trial. METHODS: A randomized multicenter study to address which, if any, of the following adjuvant treatments are of benefit in patients with resectable pancreatic cancer: radiotherapy (40 Gy with 5-FU as a sensitizing agent), 6 mo of chemotherapy (5-FU and folinic acid), or a combination of these treatments. RESULTS: From February 1994 to June 1996 (the time of the Mannheim meeting) 221 patients so far have been recruited into the three treatment arms and one control arm.

Adenocarcinoma↗
PubMed1997

ESPAC-1 trial progress report: the European randomized adjuvant study comparing radiochemotherapy, 6 months chemotherapy and combination therapy versus observation in pancreatic cancer.

At the joint International Association of Pancreatology and European Pancreatic Club meeting at King's College, London (July 9-12, 1997), a satellite meeting of the European Study Group for Pancreatic Cancer (ESPAC) met to discuss the progress of the ESPAC-1 trial. This study will address which, if any, of the following adjuvant treatments are of benefit in patients with resectable pancreatic cancer: radiotherapy (40 Gy with 5-fluorouracil as a sensitising agent); 6 months chemotherapy (5-fluorouracil and folinic acid), or a combination of these treatments. The study, which commenced in 1994, had already recruited 348 patients into the 3 treatment arms and 1 control arm of the study by May 31, 1997. This is the largest study of its kind in pancreatic cancer and should definitively address the question of the role of conventional methods of adjuvant treatment in pancreatic cancer.

Chemotherapy, Adjuvant↗
PubMed1997

Postictal neurogenic pulmonary edema: experience from an ECT model.

Neurogenic pulmonary edema (NPE) is thought to rarely occur after seizures. Paradoxically, NPE is frequently found (>80%) at autopsy in epileptic patients who die unexpectedly. The reason for the discrepancy between the frequency of NPE found at autopsy and that after uncomplicated seizures is unclear. The literature suggests that subclinical NPE occurs rarely after uncomplicated seizures and resolves within a few hours, but is undetected because of infrequent use of routine chest radiographs early after a seizure occurs. This pilot study examined the frequency of subclinical, radiographically confirmed NPE after electroconvulsive therapy (ECT)-induced seizures. If shown to occur, ECT-induced subclinical NPE would provide an easily reproducible model to study NPE after seizures in patients with epilepsy. Given that sudden unexplained death syndrome accounts for approximately 10% of the deaths in patients with epilepsy, an easily reproducible model for NPE would have heuristic value. We examined 12 patients undergoing ECT for depression with chest radiographs before and after ECT. In this group, only 1 of the 12 patients had subclinical NPE in their post-ECT radiograph. We conclude that subclinical NPE does not significantly occur after seizures in patients undergoing ECT and therefore, would not serve as an application for research.

Aged↗
PubMed1995

[Clinical studies of the incidence of pulmonary and extrapulmonary tuberculosis].

On the whole 797 patients (mean age 49.5 +/- 18.6 years) with tuberculosis who were hospitalized during 1987 and the first half of the year 1994 were investigated. 148 (18.6%) of these patients were foreigners. Regarding the age, the patients of German origin were mostly above 40 years (70.5%). Within the group of foreigners, 61.5% were below 40 years. 83.3% of the patients suffered from pulmonary and 11.4% from extrapulmonary and 11.4% from extrapulmonary tuberculosis. 5.3% of these patients had both manifestations. The tuberculin tine test was positive in 95.7% and negative in 4.3%. In 63.9% of all patients the tuberculosis was localized in the upper lobe of the lung. The tuberculosis was established bacteriologically in 56.0% and histologically in 16.5%. Both methods were applied in 13.6%. The tuberculosis was deteriorated by chronic alcoholism. Malignant diseases were recorded in 17 (2.1%) of the patients. 22 (2.8%) died during their stay at the hospital.

Adult↗
PubMed1991

Rapid antimicrobial susceptibility testing of gram-negative bacilli using Baxter MicroScan rapid fluorogenic panels and autoSCAN-W/A.

The MicroScan Rapid Neg MIC/Combo panels and autoSCAN-W/A (Walk Away) system utilize automated fluorescence technology for rapid antimicrobial susceptibility testing of Gram-negative bacilli. In a three site clinical study eleven antimicrobial agents were evaluated by comparing results obtained with 741 clinical isolates, using rapid fluorogenic expanded dilution MIC panels and corresponding frozen microdilution reference panels determined visually. Results for 31%, 40%, 12% and 9% of the isolates were available within 3.5, 4.5, 5.5 and 7.0 hours respectively. Results for 7.3% were not available within that time period. For the seven drugs analyzed using a Minimum Inhibitory Concentration range of dilutions, overall agreement (+/- 1 dilution) was 94%, with 1.5% very major, 0.9% major and 2.5% minor errors. For the four drugs analyzed using a Breakpoint range of dilutions, overall agreement (+/- 1 dilution) was 97%, with two percent very major, and one percent major errors. The MicroScan Rapid Neg MIC system is an accurate and rapid method for same day determination of susceptibility of Gram-negative bacilli.

Anti-Bacterial Agents↗
PubMed1991

Primary care and the asymptomatic HIV patient.

Most patients with HIV infections are asymptomatic or minimally symptomatic. Primary care physicians can play a unique and vital role in their care. They should: 1. Look for cases. Treatment can prevent or delay progression of disease. 2. Know how to interpret the serologic tests for HIV infection. 3. Collect an adequate data base to assess extent and severity of disease and screen for certain coexisting infections. 4. Intervene appropriately with counseling and prophylactic therapy. 5. Refer early when neoplasia, opportunistic infections, or diagnostic uncertainties occur.

HIV Infections↗
PubMed1990

Sleep modulation of neuroendocrine function: developmental changes in gonadotropin-releasing hormone secretion during sexual maturation.

To assess sleep-associated changes in gonadotropin-releasing hormone secretion during sexual maturation, we studied nighttime and daytime patterns of LH and FSH secretion in two groups with qualitatively similar sex steroid levels: girls with central precocious puberty and young adult women in the early follicular phase of an ovulatory menstrual cycle. In the girls with central precocious puberty, all indices of LH secretion were significantly higher at night than during the day (mean LH levels, 12 +/- 2 versus 5 +/- 1 IU/L, p less than or equal to 0.01; LH pulse amplitude 16 +/- 2 versus 7 +/- 1 IU/L, p less than or equal to 0.01; and LH pulse frequency 0.70 +/- 0.05 versus 0.35 +/- 0.08 pulse/patient-h, p less than or equal to 0.01). Girls with a history of menses, who were presumably the most mature, lacked this diurnal variability. Mean nocturnal FSH levels were only slightly higher than daytime levels (7.6 +/- 0.5 versus 7.2 +/- 0.5 IU/L, p less than or equal to 0.05) resulting in alternating periods of LH (nighttime) and FSH (daytime) predominance in this pubertal population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Testosterone and oxandrolone, a nonaromatizable androgen, specifically amplify the mass and rate of growth hormone (GH) secreted per burst without altering GH secretory burst duration or frequency or the GH half-life.

We investigated the mechanisms by which androgens increase mean circulating GH concentrations in boys. We tested two hypotheses: 1) testosterone increases serum GH concentrations at least in part via an androgen receptor-mediated mechanism, rather than exclusively by way of aromatization to estrogen; 2) androgen augments one or more specific features to GH secretion (secretory burst number, amplitude, and/or duration) and/or prolongs the half-life of GH removal. To examine these hypotheses, prepubertal boys with constitutionally delayed development and/or growth were given injections of testosterone (100 mg monthly; n = 7) or treated with oral oxandrolone, a nonaromatizable androgen (1.25 mg twice daily; n = 5). Pulsatile GH release was studied before and during androgen administration by sampling blood at 20-min intervals for 24 h. The immunoreactive GH time series were subjected to a novel deconvolution technique, which revealed that 1) testosterone and oxandrolone each increased mean (24-h) serum GH concentrations significantly; 2) both androgens augmented the daily endogenous GH secretory rate significantly; 3) increased GH production resulted from a higher mass of GH secreted per burst and a higher maximal rate of GH secretion within each burst; and 4) androgens amplified the magnitude of the nyctohemeral rhythm in the mass (but not frequency) of GH secretory pulses. The observed effects of androgen were specific, since the number and duration of GH secretory bursts and the subject-specific GH half-life were unaltered by androgen treatment. We conclude that androgen acting apart from conversion to estrogen is capable of specifically activating the somatotropic axis via distinct neuroendocrine secretory mechanisms.

Adolescent↗
PubMed1988

Impact of sex steroids and their suppression on skeletal growth and maturation.

Forty girls with central precocious puberty (CPP) were studied before and during 1-3 yr of luteinizing hormone-releasing factor (LHRH) agonist (LHRHa) administration to examine the impact of gonadal steroid secretion and its suppression on skeletal growth and maturation. Pubertal growth velocity (GV) was 10.1 +/- 0.7 (SE) cm/yr and, when normalized for chronological age (CA) and bone age (BA), demonstrated that the effects of sex steroids were most profound in patients with the youngest CA and BA. GV decreased significantly to 5.8 +/- 0.3 (n = 40), 4.6 +/- 0.3 (n = 30), and 3.2 +/- 0.6 cm/yr (n = 12) during 3 yr of gonadal suppression and correlated negatively with starting BA. Skeletal maturation was markedly accelerated by premature sex steroid secretion (BA/CA = 1.8 +/- 0.1), was slowed significantly with gonadal suppression (mean delta BA/delta CA less than 1), and also was negatively correlated with the starting BA. Cumulative increases in predicted adult height were observed regardless of starting BA and averaged +2.0 +/- 0.4, +5.2 +/- 0.5, and +6.7 +/- 1.2 cm after 1, 2, and 3 yr of gonadal suppression. The comparable changes in height predictions across all BAs despite highly variable GVs underscore the need for use of developmental (i.e., BA-based) rather than CA-based standards in the analysis of growth during gonadal steroid exposure and suppression in childhood.

Body Height↗
PubMed1987

Augmentation of growth hormone secretion during puberty: evidence for a pulse amplitude-modulated phenomenon.

The augmentation of GH secretion that occurs during puberty has been attributed to changes in sex steroid levels that enhance the frequency and amplitude of GH pulses. To investigate the specific GH pulse characteristics responsible for such augmentation we analyzed the serum GH concentration profiles of 10 boys in Tanner stages I-II of sexual development (group A; aged 10 5/12-15 1/12 yr) and compared their GH pulse characteristics with those of 5 boys at Tanner stages IV-V of development (group B; aged 14 8/12-15 1/12 yr). We also reanalyzed previously reported data from 5 prepubertal boys (group C; aged 13 6/12-15 5/12 yr) before and after 10 weeks of treatment with testosterone enanthate (100 mg/4 weeks, im). Using a pulse detection algorithm that constrains the false positive pulse detection rate to less than 5% (Cluster), we found that group B boys had a significantly higher mean serum GH pulse amplitude compared to group A boys (17.1 +/- 2.6 vs. 8.6 +/- 1.7 ng/mL; P = 0.012), but both groups had the same mean GH pulse frequency (group B, 5.4 +/- 0.5 pulses/24 h vs. group A, 5.5 +/- 0.4 pulses/24 h; P greater than 0.05). Similar changes were found in group C boys before and after testosterone therapy; there was no significant change in GH pulse frequency (6.6 +/- 0.9 before vs. 7.6 +/- 0.5 pulses/24 h after treatment; P greater than 0.05), but there was a significant increase in the GH pulse amplitude after therapy (6.8 +/- 1.6 before vs. 15.4 +/- 2.4 ng/mL after treatment; P = 0.04). When the 24-h GH concentration profiles were analyzed using a mathematically distinct method for the estimation of pulse amplitudes, namely the Fourier expansion time series, we confirmed a significant increase in GH pulse amplitude with later stages of puberty and androgen treatment. We conclude that the augmentation in GH secretion that occurs during either spontaneous puberty or exogenous testosterone therapy is an amplitude-modulated phenomenon, relatively independent of changes in pulse frequency. Such an effect may be secondary to the action of sex steroid hormones modulating either the responsivity of somatotrophs to endogenous GH-releasing hormone, the amount of GH-releasing hormone secreted, or the tonic inhibitory tone of somatostatin.

Adolescent↗
PubMed1986

The effect of androgens on the pulsatile release and the twenty-four-hour mean concentration of growth hormone in peripubertal males.

Oxandrolone (Ox) and testosterone (T) are used as growth-promoting agents in the therapy of boys with constitutional delay of growth and adolescence. Although the mechanism of action of these androgens is not known, it is recognized that T enhances GH release during GH stimulation tests. We studied the effects of T and Ox on the mean concentration of GH, the pattern of GH secretion, and somatomedin-C (SmC) concentrations in boys with short stature and/or delayed sexual development to determine whether their growth-promoting effects might be mediated through endogenous GH release. Ten boys received Ox (0.1 mg/kg . day, orally) for 65 +/- 5 days (mean +/- SD), and five boys received T propionate (7.5 mg, im, for 7 days), followed by T enanthate (100 mg, im, monthly for 3 months). Serum GH was measured in samples obtained at 20-min intervals for 24 h before and 65 +/- 5 days (mean +/- SD) after the initiation of therapy. SmC levels were measured twice during the same 24-h period before and 65 +/- 5 days (mean +/- SD) after initiation of therapy. In the boys treated with T, there were significant increases in the mean concentration of GH (mean increase, 4.3-fold; range, 2-12), in the number of GH pulses 10 ng/ml or greater [1.6 +/- 2.0 vs. 4.8 +/- 1.5/24 h (mean +/- SD)], and in the SmC levels [0.82 +/- 0.46 vs. 2.3 +/- 0.4 mu/ml (mean +/- SD)]. There were, however, no significant changes in the boys treated with Ox. Both Ox and T significantly improved the growth rates; however, T increased the growth rate by 0.95 +/- 0.24 (mean +/- SD) cm/months, and Ox increased the growth rate by 0.24 +/- 0.26 (mean +/- SD) cm/month. These results indicate that T, but not Ox, at the doses tested increases GH secretion in boys with short stature and/or delayed sexual development. This increase in GH secretion may contribute to the increased growth rate in males at puberty.

Adolescent↗
PubMed1984

Why physicians don't pursue abnormal laboratory tests: an investigation of hypercalcemia and the follow-up of abnormal test results.

For unknown reasons, physicians often ignore unsolicited clinical data. This is thought to impair the quality of medical care and the efficacy of screening programs. To investigate this problem the authors followed 156 consecutive hypercalcemic patients for nine to 15 months. Twenty-eight were lost to follow-up, and the hypercalcemia was ignored in 26. Calcium tests were repeated for 102, and hypercalcemia was confirmed in 53. Of these, 39 were and 14 were not further investigated. Analysis by logistic regression revealed a highly significant relationship between the degree of hypercalcemia and the likelihood that calcium testing would be repeated or that abnormal levels would be further investigated. The authors conclude that, contrary to common opinion, when physicians ignore abnormal laboratory values they are making complex clinical judgments based on the degree of abnormality, the likelihood that further investigation will affect therapy, and the cost of the risk associated with further investigation. Evaluation and attempts to modify this behavior should take into account the complexity of these decisions.

Adult↗
PubMed1984

An agenda for residency training in ambulatory care.

The successful practice of internal medicine in the ambulatory setting must take into consideration a number of factors that differ qualitatively and quantitatively from those important to practice on the hospital ward. The physician's intellectual ability, understanding of pathophysiology, and competence in physical examination are indispensable to practicing in both settings. However, due to the nature of presenting problems, the availability of time, and the role of patient cooperation, the application of these skills and knowledge and the decision-making process differ in the two settings. The recognition of these factors by the resident is likely to enhance his understanding of his therapeutic role, further his capacity to provide care to a diverse spectrum of patients, and promote greater satisfaction for himself and his patients. These considerations are especially important because most practicing internists spend most of their clinical time in the ambulatory settings.

Ambulatory Care↗