Optimization of skin dose using in-vivo MOSFET dose measurements in bolus/non-bolus fraction ratio: A VMAT and a 3DCRT study

In‐phantom and in‐vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected. Skin dose showed higher values with 3DCRT technique compared with VMAT. The increase in skin dose due to the use of bolus was quantified. It was observed that, in the case of VMAT, the bolus effect on the skin dose was considerable when compared with 3DCRT. From the point of view of treatment time, bolus cost, and positioning reproducibility, the use of bolus in these situations can be optimized.

Lack of association of CYP1A1-MspI SNP and GSTM1 null genotypes with cancer in a Brazilian family with unusually high cancer incidence

Research has shown that genetic polymorphisms in biotransformation enzymes, such as CYP1A1 and GSTM1, are related to a greater or lesser susceptibility to various cancers. We made an analysis of CYP1A1m1 SNP and GSTM1 null genotypes in a family group (71 members) related by consanguinity who had an unusually high incidence of cancer and a high frequency of smokers. There were no significant differences in genotype frequencies in this family when compared to data for Brazilian populations. Possibly, the high incidence of cancer in this sample is associated with smoking and/or other factors not detected in this survey.

Early onset of primary hypogonadism revealed by serum anti-Müllerian hormone determination during infancy and childhood in trisomy 21

Male patients with an extra sex chromosome or autosome are expected to present primary hypogonadism at puberty owing to meiotic germ-cell failure. Scarce information is available on trisomy 21, a frequent autosomal aneuploidy. Our objective was to assess whether trisomy 21 presents with pubertal-onset, germ-cell specific, primary hypogonadism in males, or whether the hypogonadism is established earlier and affects other testicular cell populations. We assessed the functional status of the pituitary-testicular axis, especially Sertoli cell function, in 117 boys with trisomy 21 (ages: 2months-20year). To compare with an adequate control population, we established reference levels for serum anti-Müllerian hormone (AMH) in 421 normal males, from birth to adulthood, using a recently developed ultrasensitive assay. In trisomy 21, AMH was lower than normal, indicating Sertoli cell dysfunction, from early infancy, independently of the existence of cryptorchidism. The overall prevalence rate of AMH below the 3rd percentile was 64.3% in infants with trisomy 21. Follicle-stimulating hormone was elevated in patients <6months and after pubertal onset. Testosterone was within the normal range, but luteinizing hormone was elevated in most patients <6months and after pubertal onset, indicating a mild Leydig cell dysfunction. We conclude that in trisomy 21, primary hypogonadism involves a combined dysfunction of Sertoli and Leydig cells, which can be observed independently of cryptorchidism soon after birth, thus prompting the search for new hypotheses to explain the pathophysiology of gonadal dysfunction in autosomal trisomy.

Premature thelarche: clinical and laboratorial assessment by immunochemiluminescent assay

In order to establish cut-off limits and to distinguish isolated premature thelarche (IPT) from precocious puberty (PP), we evaluated data from 79 girls with premature thelarche, comparing basal and stimulated LH and FSH serum concentrations with those from 91 healthy girls. A GnRH stimulation test was performed in 10 normal girls and in 42 with premature thelarche. Comparison among groups was performed by Kruskal-Wallis and Dunns tests. LH values were significantly greater in girls with IPT than in control groups. Basal gonadotropin concentrations were higher in patients with PP than in controls, but not different from patients with IPT. Peak LH levels after GnRH stimulation distinguished those two groups, with a cut-off value of 4.0 IU/L, but still with minimal overlap. In conclusion, a girl with premature thelarche and LH peak value above 4.5 IU/L has, indeed, PP, but values between 3.5 and 4.5 IU/L point to careful follow-up.

Assessment of basal and gonadotropin-releasing hormone-stimulated gonadotropins by immunochemiluminometric and immunofluorometric assays in normal children

CONTEXT

Recently, new methodologies have been applied to commercial immunofluorometric (IFMA) and immunochemiluminometric (ICMA) LH and FSH assays.

OBJECTIVE

The objective of the study was to use ICMA to establish basal and GnRH-stimulated LH and FSH reference values in normal subjects of different ages and sexual development, compared with IFMA.

DESIGN AND METHODS

We established basal and GnRH-stimulated LH and FSH levels of 315 prepubertal and pubertal children (170 males and 145 females) divided into five groups according to Tanner stage. Of these, 106 subjects (59 males and 47 females) were submitted to GnRH test. The prepubertal upper limit of normal for basal LH, determined by the 95th percentiles of the prepubertal population, were 0.2 IU/liter (ICMA) and 0.6 IU/liter (IFMA) in both genders.

RESULTS

No overlap of basal LH levels determined by ICMA was observed between prepubertal and pubertal males, but basal LH determined by IFMA overlapped in 11.8% of subjects. In girls, both methods yielded overlapping values (10.4%, ICMA; and 84.6%, IFMA). The LH peak after GnRH stimulation that defined puberty was 4.1 IU/liter (ICMA) and 3.3 IU/liter (IFMA) in boys and 3.3 IU/liter (ICMA) and 4.2 IU/liter (IFMA) in girls. After GnRH stimulation, values determined by the two methods overlapped in both genders.

CONCLUSIONS

We conclude that ICMA is more sensitive and precise than IFMA, permitting differentiation of pubertal and prepubertal stage in boys under basal conditions. However, in girls the overlap of basal values was marked, indicating the need for the GnRH test to establish maturity of the hypothalamus-pituitary-gonadal axis.

C-cells in colloid goiter

PURPOSE: The aim of this investigation was to quantitatively evaluate C-cells in colloid goiters, analyzing 36 thyroids that were obtained through thyroidectomy from 24 patients with goiter and 12 normal glands from adult patients without thyroid disease, which were used as the control group. MATERIAL AND METHODS: On average, 6 different thyroid areas were sampled and labeled by immunohistochemistry with a monoclonal anticalcitonin antibody, utilizing the avidin-biotin-peroxidase complex. C-cells were counted in fields measuring 1 square centimeter, and the mean number of cells per field was then calculated. Data were statistically analyzed using the Mann-Whitney test. RESULTS: In the colloid goiter group, the number of C-cells ranged from 0 to 23 per field, while in normal controls they ranged from 20 to 148 per field. CONCLUSIONS: These results demonstrate a significant decrease of C-cell number in the colloid goiter group compared with control group, indicating that the hyperplastic process is restricted to follicular cells, to the detriment of C-cells, which probably cease to receive trophic stimuli.

Pubarca precoce: estudo retrospectivo clínico e laboratorial

Analisaram-se 109 prontuários de pacientes atendidos no período de janeiro de 1990-2000, cujo diagnóstico era pubarca precoce, com o objetivo de se avaliar a etiologia e evolução destes pacientes. Os mesmos foram divididos em 4 grupos: G1, n=41 (35F/6M, idades entre 11 meses e 7anos e 11 meses, mediana: 7anos e 1 mês), nos quais foram dosados: 17-OH progesterona (17OHP), DHEA, DHEA-S, androstenediona, testosterona total e/ou livre, e feito teste de estímulo do LH e FSH com GnRH (Relisorm®, 100mig iv); no grupo G2, n=28 (20F/8M, idades entre 9meses e 8anos e 11 meses, mediana: 7anos e10meses), além dos exames mencionados, investigou-se a deficiência da 21-hidroxilase através da dosagem de 17OHP sob estímulo agudo com ACTH (Cortrosina®, 250mig iv), O grupo G3, n=23 (19F/4M, idades entre 1ano e 2meses e 8anos e 10meses, mediana: 7anos e 6meses), além dos exames anteriores, foi investigado para deficiências de 11 beta-hidroxilase e 3beta-hidroxi-esteróide desidrogenase pelas dosagens de 11-deoxicortisol, e relação DHEA/androstenediona, respectivamente. As dosagens de testosterona total e/ou livre, DHEA-S e estradiol (em meninas) foram feitas nos 3 grupos. No grupo G4, n=14 (12F/2M, idades entre 1ano e 1 mês e 8anos e 9meses, mediana: 6anos e 5meses) o diagnóstico foi feito apenas com dados clínicos. Três meninas (6meses, 2anos e 1 mês e 2anos e 7meses) foram consideradas à parte; tiveram puberdade precoce associada a hiperandrogenismo, como primeira manifestação de adenocarcinoma adrenal. A investigação demonstrou níveis muito elevados de DHEA-S e massas adrenais ressecadas posteriormente. Um grupo controle de 18 crianças normais pré-púberes (8F/10M) foi submetido ao teste agudo do ACTH. No estímulo com GnRH, um delta LH > ou = 7,0 foi considerado indicativo de resposta púbere. Andrógenos e estradiol foram dosados por RIE e kits comerciais DPC; LH e FSH foram dosados por métodos imunométricos. As respostas entre pacientes e grupo controle foram comparadas pelo teste de Mann-Whitney. Nos grupos G1, G2 e G3 apenas 4 pacientes responderam com um delta LH > ou = 7,0 e 2 evoluíram com puberdade precoce verdadeira. A resposta da 17OHP ao ACTH (G2 e G3, n=51) diagnosticou 2 casos de deficiência da 21-hidroxilase, forma não-clássica. Nos outros, as respostas não diferiram do grupo controle. Não houve acúmulo de outros precursores testados pelo ACTH no G3. Concluímos que uma minoria de crianças com adrenarca precoce evoluem para puberdade precoce ou têm hiperplasia adrenal congênita na forma não clássica, o que mostra que, após avaliação dos níveis de esteróides basais, o seguimento apenas clínico seria mais prático e econômico, deixando a realização de testes para quando houvesse algum dado inicial ou evolutivo que o indicasse.

Diagnostic value of fluorometric assays in the evaluation of precocious puberty

To establish normative data and determine the value of fluorometric AutoDELFIA assays (Wallac Oy) in the investigation of precocious puberty, we determined serum levels of LH, FSH, testosterone, and estradiol under basal and GnRH-stimulated conditions in 277 normal subjects at various pubertal stages and in 77 patients with precocious puberty. A substantial overlap was observed in basal and GnRH-stimulated gonadotropin levels in normal individuals of both sexes with pubertal Tanner stages 1 and 2. The 95th percentile of the normal prepubertal population was the cut-off limit between prepubertal and pubertal levels. These limits were 0.6 IU/L in both sexes for basal LH, 9.6 IU/L in boys and 6.9 IU/L in girls for peak LH after GnRH stimulation, 19 ng/dL in boys for basal testosterone, and 13.6 pg/mL in girls for basal estradiol. Basal and peak LH exceeding these limits were considered positive tests for the diagnosis of gonadotropin-dependent precocious puberty. According to these criteria, the sensitivities of basal and peak LH for the latter diagnosis were 71.4% and 100% in boys, and 62.7% and 92.2% in girls. The specificity and positive predicted value were 100% in both sexes for basal and peak LH levels. The negative predicted values for basal and peak LH were 62.5% and 100% in boys, and 40.6% and 76.5% in girls. Basal and GnRH-stimulated FSH levels overlapped among the various pubertal stages in normal subjects and were, in general, not helpful in the differential diagnosis of precocious puberty. In conclusion, basal LH levels were sufficient to establish the diagnosis of gonadotropin-dependent precocious puberty in 71.4% of boys and 62.7% of girls. In the remaining patients, a GnRH stimulation test was still necessary to confirm this diagnosis. Finally, suppressed LH and FSH levels after GnRH stimulation indicate gonadotropin-independent sexual steroid production.

Calcitonin deficiency in early stages of chronic autoimmune thyroiditis

OBJECTIVES

Although calcitonin (Ct) deficiency has been described in chronic autoimmune thyroiditis (CAT) it is unclear at what stage in the disease it develops. We have analysed the Ct secretory responses of patients in two different evolutionary stages of CAT, namely the goitrous and atrophic phases.

DESIGN

We studied the Ct response to combined calcium (2 mg/kg) and pentagastrin (0.5 microgram/kg) intravenous infusion in 27 patients with CAT and 30 normal adult controls. The cases were divided into two groups. The first comprised eleven women with CAT and goitrous subclinical hypothyroidism (GH), aged 28.6 +/- 10.1 years--at diagnosis they had increased thyroid autoantibody titres and cytological features compatible with stages 1 and 2 of Hashimoto's thyroiditis. The second comprised 16 females with CAT and an atrophic thyroid confirmed by ultrasound scan, aged 38.0 +/- 9.2 years--these patients were severely hypothyroid at diagnosis and were termed AH (atrophic hypothyroidism). Both groups (GH and AH) received replacement doses of thyroxine sufficient to restore euthyroidism for at least six months before the stimulation tests. Control group (C) consisted of 20 healthy women (A), aged 30.0 +/- 9.6 years, and 10 healthy men (B), aged 34.7 +/- 8.0 years. Serum Ct was measured by IRMA. The Ct secretory response was related to thyroid size and cytological data, when available.

RESULTS

Basal Ct concentrations in groups GH (0.08 ng/l, median) and AH (0.07 ng/l, median) were significantly lower than those of female controls (0.58 ng/l, median). Stimulated Ct peak values in groups GH (0.08 ng/l, median) and AH (0.19 ng/l, median) were significantly lower than those of female controls (13.61 ng/l, median). Also, both basal (2.72 ng/l, median) and stimulated Ct levels (35.73 ng/l, median) in male controls were significantly higher than in female controls given already. A positive correlation between the Ct secretory reserve and thyroid dimensions, evaluated by ultrasound scan, was found only in patients with thyroid atrophy (AH; rs = 0.61, P < 0.05).

CONCLUSIONS

We have found low basal and stimulated calcitonin values in patients with chronic autoimmune thyroiditis and thyroid enlargement, which represents an early phase of chronic autoimmune thyroiditis. Our data have also confirmed previous findings of deficient calcitonin secretion in advanced stages of chronic autoimmune thyroiditis in which thyroid atrophy is usually found. These findings may be associated with C-cell destruction following progressive, nonspecific follicular cell damage caused by lymphocytic infiltration and fibrosis of the gland.

Quantitative analysis of C cells in Hashimoto's thyroiditis

The objective of the present investigation was to study quantitatively C cells in Hashimoto's thyroiditis (HT) by analyzing 22 thyroids obtained at autopsy or thyroidectomy from 16 patients with thyroiditis and from 6 normal subjects. Six different areas were sampled on average and labeled with a monoclonal anticalcitonin antibody by immunohistochemistry using the avidin-biotin-peroxidase complex. Normal thyroids from adult patients with no thyroid disease were used as control. C cells were counted in 1 cm2 fields and the mean number of cells per field was calculated. Data were analyzed statistically by the Mann-Whitney test. The inflammatory process detected in cases of HT was usually moderate (50%) and the number of C cells ranged from 0 to 12.2 per 1 cm2 field. The number of C cells in normal thyroids ranged from 20 to 148 per 1 cm2 field, with a median of 35.2 cells per field. The results demonstrate a significant decrease in C cell number in HT compared with normal thyroids, indicating that the inflammatory process causes destruction of both follicular and C cells, which are replaced by fibrosis.

Minimally invasive coronary bypass surgery: postoperative pain management using intermittent bupivacaine infiltration

Minimally invasive direct coronary artery bypass grafting (MIDCAB) is becoming a popular adjunct to standard cardiac bypass surgery in selected patients with accessible single or double vessel disease. However, the limited anterior thoracotomy used to access the heart involves trauma to the muscle tissue during removal of the fourth costal cartilage and a small piece of connected rib, perhaps leading to more severe postoperative pain compared with patients undergoing routine sternotomy. Intrathecal opioids can be used but have limited therapeutic duration and there is concern regarding anticoagulation. We present a case where soft tissue catheters were placed into the depths of the surgical wounds and pain was diminished greatly by intermittent regular infiltration with bupivacaine.

Arrhythmia/ischemia management during minimally invasive cardiac operation

We present a case of severe arrhythmia and hemodynamic compromise in a patient undergoing minimally invasive coronary artery bypass grafting without cardiopulmonary bypass. This was successfully treated via an extracorporeal shunt from a femoral artery cannula.

Substituted xanthones as selective and reversible monoamine oxidase A (MAO-A) inhibitors

1,3-Dihydroxy-2-methylxanthone (X1), its 4-chloro and 4-bromo derivatives (X1-Cl and X1-Br), and 1,3-dihydroxy-4-methylxanthone were investigated for their inhibition activities toward MAO. A hyperbolic function was derived to fit the data and to calculate IC50 values. The compounds proved to be reversible and selective inhibitors of MAO-A, with X1 displaying the highest activity (IC50 = 3.7 microM).

Serum testosterone fractions in women: normal and abnormal clinical states

The potential usefulness of determining serum testosterone (T) fractions in women, ie, sex hormone-binding globulin (SHBG)-bound T, albumin-bound T (Alb-T), and free T (FT) fractions, was explored in a variety of clinical situations. Serum T, SHBG, and albumin concentrations were measured by standardized methods and using binding constants of T to SHBG and albumin, we calculated serum T fractions, which agreed remarkably with measured values of SHBG-T and nonbound T. Serum T levels did not change in normal women examined during the follicular and luteal phases of the menstrual cycle, but SHBG levels were elevated in the luteal phase, changing the distribution of T, with increased SHBG-T and less T distributed to other fractions. Women taking oral contraceptives had decreased serum T levels, but use of androgen-like oral contraceptives decreased SHBG levels and T distribution to this binding protein, whereas use of non-androgen-like oral contraceptives increased SHBG levels, resulting in the expected shift of T fractions. Women receiving phenytoin for seizure disorders and women with Graves' disease exhibited increased SHBG levels with concomitant increased SHBG-T and decreased distribution of T to nonbound fractions. Women with hirsutism exhibited decreased SHBG levels irrespective of total serum T levels, and the T/SHBG ratio was elevated in this population. However, of interest were women with morbid obesity (nonhirsute) who had similar low levels of SHBG and T/SHBG ratios that were indistinguishable from those of hirsute women.(ABSTRACT TRUNCATED AT 250 WORDS)