Biomedical subjects

G Federico

Publications and source records attributed to G Federico.

At least 19 recordsLinked to original sources

PubMed2006

Assessment of serum IGF-I concentrations in the diagnosis of isolated childhood-onset GH deficiency: a proposal of the Italian Society for Pediatric Endocrinology and Diabetes (SIEDP/ISPED).

The diagnosis of GH deficiency (GHD) is based on the measurement of peak GH responses to pharmacological stimuli. Pharmacological stimuli, however, lack precision, accuracy, are not reproducible, are invasive, non-physiological and some may even be hazardous. Furthermore, different GH commercial assays used to measure GH in serum yield results that may differ considerably. In contrast to GH, IGF-I can be measured on a single, randomly-obtained blood sample. A review of the available data indicates that IGF-I measurement in the diagnosis of childhood-onset isolated GHD has a specificity of up to 100%, with a sensitivity ranging from about 70 to 90%. We suggest an algorithm in which circulating levels of IGF-I together with the evaluation of auxological data, such as growth rate and growth, may be used to assess the likelihood of GHD in pre-pubertal children.

Age of Onset↗

PubMed2006

How do environmental estrogen disruptors induce precocious puberty?

Puberty is regulated by the endocrine system. Disruption of that system by exposure to environmental hormone-mimicking substances (i.e. endocrine disruptors) may, therefore, affect this development profoundly. There has been a great secular trend in the earlier timing of puberty such as both puberty onset and menarche age. This is apparently caused by environmental factors such as improved socioeconomic status, better healthcare and improved nutrition. However, part of the phenomenon could be associated with exposure to endocrine disruptors that have intrinsic estrogen activity or increase endogenous sex hormone levels. These estrogen pollutants tend to degrade slowly in the environment, to bioaccumulate in the food chain and to have long half-lives in humans. Because most of environmental chemicals, called estrogen disruptors or xenoestrogens, are toxic and estrogen/antiandrogen active, they can disregulate hypothalamic-pituitary-gonadal axis potentially inducing reproductive disorders. There are several case reports of accidental exposure to estrogenic compounds in cosmetic products, food and pharmaceuticals. The outbreak of epidemics of premature thelarche in some geographical areas has also been suggested to be linked to exposure to estrogen disrupters such as dioxins, furans and organohalogens. We review data on adverse health and reproductive outcomes have been attributed to estrogen disruptors in laboratory animals and in wildlife as well as in humans, specially focusing on the puberty timing.

Age Factors↗

PubMed2005

Vitamin D status in patients affected by Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an inborn error of cholesterol biosynthesis characterized by developmental delay and multiple malformations. Some of the patients have skin photosensitivity and therefore tend to avoid direct exposure to sunlight.SLOS patients typically have low concentrations of cholesterol and abnormally high concentrations of its precursor 7-dehydrocholesterol (7-DHC) in biological fluids and tissues. 7-DHC is also a precursor in the cutaneous synthesis of vitamin D. Sunlight exposure plays a major role in this pathway and reactions transforming 7-DHC into vitamin D and then into 25-hydroxyvitamin D are known not to be specifically regulated. The aim of this study was to evaluate vitamin D status in SLOS patients. We measured 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D serum concentrations and markers of calcium metabolism in five SLOS patients. Despite abnormally high concentrations of 7-DHC, circulating concentrations of vitamin D metabolites were not significantly different from appropriate controls matched for sex, age and season of blood collection. The analysis of historical serum samples stored in our laboratory from the same cases plus 10 other SLOS patients further supported these findings. Our data suggest that SLOS patients have a peculiar vitamin D metabolism that protects them from vitamin D intoxication. This appears to be due in most cases to decreased transformation of 7-DHC into 25-hydroxyvitamin D, perhaps depending on reduced sunlight exposure as a consequence of photosensitivity. Possible alternative mechanisms are discussed.

Adolescent↗

PubMed2005

[Evaluation of sexual activity after prostatic surgery for benign prostatic hyperplasia assessed by pre-operative and post-operative questionnaire].

AIM: Different authors showed a 5-40% incidence of erectile dysfunction after prostatic surgery for benign prostatic hyperplasia. The aim of our study was to evaluate the effect of prostatic surgery due to benign prostatic hyperplasia on sexual activity. METHODS: We evaluated 56 patients (mean age 63 years, range 49-70) who underwent transurethral resection of the prostate (30 patients, mean age 64 years, range 56-70) and open prostatectomy (26 patients, mean age 59 years, range 49-70) with a questionnaire regarding the presence of sexual dysfunction before and 3, 6, 12 months after surgery. All patients were not affected by previous or present metabolic, neurological, cardiovascular diseases. RESULTS: Twenty percent of the patients with a normal sexual activity before treatment presented erectile dysfunction after surgery. However, 35% of patients with erectile dysfunction before treatment presented an improvement of their erectile function after surgery. CONCLUSIONS: A high incidence of erectile dysfunction was observed in patients undergoing prostatic surgery. Patients with erectile dysfunction should also recover a normal behaviour after prostatic surgery as well as an improvement of the erectile dysfunction.

Aged↗

PubMed2004

Indications and strategies for continuing GH treatment during transition from late adolescence to early adulthood in patients with GH deficiency: the impact on bone mass.

GH plays an important role in longitudinal bone growth and maturation during childhood and adolescence. However, GH has important metabolic functions other than bone growth, which become more apparent during young adulthood, when growth has been completed. Indeed, GH deficiency (GHD) in adult life is a recognized clinical syndrome which includes symptoms such as increased central adiposity, decreased lean body mass, reduced bone mineral density (BMD), increased atherogenic risk, cerebrovascular and cardiac morbidity and mortality, and reduced quality of life. As approximately one quarter of the children with GHD should continue GH administration in adulthood, it is important to reconfirm GHD at the end of growth in order to select patients with severe GHD who need to resume GH therapy with an appropriate age-related dosage. Some evidence indicates that most peak bone mass (PBM) is achieved by the end of adolescence but small increases in BMD continue during the period of transition from late adolescence to young adulthood. Some young adults with GHD show a persistent increase of lumbar BMD after the completion of growth even after discontinuation of treatment suggesting a spontaneous progression towards lumbar PBM or a continuing effect of the treatment. The data indicates that adolescents with GHD who do not reach lumbar PBM at the time of discontinuation of GH treatment can achieve a BMD lower than their genetic potential if they are not treated during the transition to young adulthood.

Adolescent↗

PubMed2003

Best approach for prostate cancer detection: a prospective study on transperineal versus transrectal six-core prostate biopsy.

OBJECTIVES: To compare the efficacy of transperineal versus transrectal six-core prostate biopsy. Transrectal sextant biopsy is the most common method for prostate cancer detection. However, the cancer detection rate with this technique is increasingly considered inadequate. Different prostate biopsy procedures, mainly based on addition of additional transrectal cores to traditional sextant biopsy, have been proposed to increase the cancer diagnosis rate. The efficacy of the transperineal approach has not yet been fully established. METHODS: In a prospective study, 107 patients with elevated prostate-specific antigen levels (greater than 4.0 ng/mL) underwent prostate biopsy with six transperineal cores, using a "fan" scheme, plus six transrectal cores, according to the sextant technique. The median prostate-specific antigen level was 8.2 ng/mL (range 4.1 to 240). RESULTS: The overall cancer detection rate was 40% (43 of 107); prostate cancer was found in 38% (41 of 107) of patients with the transperineal approach and in 32% (34 of 107) of patients with the transrectal approach. Of 43 diagnosed cancers, 41 (95%) were found with the transperineal approach and 34 (79%) with the transrectal approach (P = 0.012). No patient had low-grade cancer (Gleason score 2 to 4), 25 patients had intermediate-grade cancer (Gleason score 5 to 6), and 18 patients had high-grade cancer (Gleason score 7 to 10). CONCLUSIONS: This is the first report comparing in vivo two different approaches to prostate biopsy. Transperineal biopsy seems superior to transrectal biopsy to detect prostate cancer. Both the transperineal and the transrectal approach should be familiar to the urologist who needs to obtain an adequate cancer detection rate. Transrectal sextant biopsy cannot be considered the standard technique for prostate cancer detection.

Aged↗

PubMed2003

Etanercept induces improvement of arthropathy in chronic infantile neurological cutaneous articular (CINCA) syndrome.

Chronic infantile neurological cutaneous articular (CINCA) syndrome is a rare disorder of unknown aetiology with neonatal onset, characterized by severe arthropathy, persistent skin rash and central nervous system disease. Joint involvement may vary from minimal swelling to destructive arthritis, with inability to stand or walk. The most striking findings of CINCA syndrome are cartilage anomalies with epiphyseal modifications and abnormal ossification, for which a pathogenetic role of tumour necrosis factor-alpha (TNF-alpha) is postulated. We describe a 4-year-old child affected with CINCA syndrome and presenting progressive joint disease, in whom non-steroidal anti-inflammatory drugs (NSAID) and systemic corticosteroidal therapy had been ineffective. Etanercept, anti-TNF-alpha therapy, was administered over a 6-month-period resulting in a dramatic improvement of the arthropathy. This good response to anti-cytokine treatment supports our hypothesis that TNF-alpha might play an important role in the pathogenesis of CINCA syndrome, which needs to be evaluated and confirmed in further studies.

Antirheumatic Agents↗

PubMed2003

High grade superficial (G3t1) transitional cell carcinoma of the bladder treated with intravesical Bacillus Calmette-Guerin (BCG).

OBJECTIVES: Immunotherapy with Bacillus Calmette Guerin (BCG) has been widely used recently as primary option for treatment of high grade superficial (G3T1) carcinoma of the bladder. We describe our long term experience of therapy of G3T1 bladder cancer. METHODS: From January 1982 to December 2000, 785 patients were diagnosed with superficial bladder cancer. All patients underwent preoperative CT scan and transurethral resection of the bladder. Eighty-six patients (11%) had histological high grade superficial bladder cancer infiltrating the lamina propria. This group was treated with the following schedule of BCG Pasteur strain plus maintenance. Four cycles BCG, 6 instillations per cycle, first cycle weekly x 6, second cycle every 2 weeks x 6, third cycle monthly x 6, fourth cycle (maintenance) every 3 months x 6 instillations. RESULTS: The median follow-up is 91 months (30-197 months). The overall recurrence rate was 35% (30/86). The median time to recurrence was 29 months (5-128 months). Of these patients, 12 (14%) had progression at a median follow-up of 16 months (range 8-58 months). Cystectomy was needed in 8 (9%) patients. Death due to disease occurred in 5/86 (6%) patients. One patient died due to adenocarcinoma at the ureterosigmoidostomy site. Sixty-four (74%) patients are alive at a median follow-up of 71 months (range 28-197 months). Sixty patients (70%) are alive with an intact bladder. CONCLUSIONS: Treatment with BCG is a feasible conservative therapy for patients with primary G3T1 transitional bladder cancer. Long term results of BCG treatment are excellent. Cystectomy shouldn't be considered first line treatment for high grade superficial carcinoma of the bladder.

Administration, Intravesical↗

PubMed2001

Risk factors and prognostic indicators of bacterial meningitis in a cohort of 3580 postneurosurgical patients.

In order to identify the incidence, risk factors and prognostic indicators of postneurosurgical bacterial meningitis, a 9-y retrospective cohort study was performed. The cohort comprised 3580 individuals who underwent neurosurgical operations at the Department of Neurosurgery of Catholic University, Rome, a 1,700-bed university hospital. We observed 52 episodes of postneurosurgical meningitis, with infection rates of 1.4/100 patients, 0.8/100 operations for craniotomies and 2.6/100 operations for internal cerebrospinal fluid (CSF) shunt or ventriculostomy with external drainage. The overall infection rate decreased from 2.5/100 operations in 1989 to 0.9/100 in 1997 (p = 0.03). Logistic regression analysis indicated that duration of ventriculostomy with external drainage [p < 0.01; odds ratio (OR) = 9.67; 95% confidence interval (CI) = 2.44-38.321 and increasing value of the APACHE III score (p <0.01; OR = 8.51; 95% CI = 2.15-33.68) were independent risk factors for development of meningitis. The overall case fatality rate was 8%. Predictors of mortality were low ( < 1.66 mmol/l) CSF glucose concentration (p = 0.001), increasing value of the APACHE IIl score (p = 0.002) and Gram-negative aetiology (p = 0.003).

APACHE↗

PubMed2001

Bone quality assessment by quantitative ultrasound of proximal phalanxes of the hand in healthy subjects aged 3--21 years.

Bone quality by quantitative ultrasound was assessed in 1083 (587 males) healthy white subjects aged 3--21 y. Amplitude-dependent speed of sound (AD-SoS) through the distal end of the first phalanx diaphysis of the last four fingers of the hand was measured by an ultrasound device (DBM Sonic 1200, IGEA, Carpi, Italy). Mean AD-SoS values increased progressively from 3 to 21 y (males, 1845.9--2119.1 m/s, p < 0.0001; females, 1842.3--2098.8 m/s, p < 0.0001). They did not differ (p = NS) between sexes up to age 11, but females showed higher (p < 0.05 - p < 0.0001) AD-SoS values than males in age groups 12, 13, and 14 y. There was no difference (p = NS) of AD-SoS values between sexes in pubertal stages 1, 2, and 5, but females had higher mean AD-SoS values than males in stages 3 (p < 0.01) and 4 (p < 0.001). Independent predictors of AD-SoS were weight, body mass index, pubertal stage, and mean width of fingers in males, and age, pubertal stage, and mean width of fingers in females (p < 0.01 - p < 0.0001). However, 7.8% in males and 3.6% in females of the increment of AD-SoS values can be related to the finger anatomy alone. AD-SoS values probably reflect the architectural organization of growing bone or changes in bone elasticity. Increased bone density and size may be additional factors influencing AD-SOS: Measurement of AD-SoS at the hand phalanxes may be a simple, noninvasive, and radiation-free technique to assess bone quality in children.

Adolescent↗

PubMed2001

The effect of administering gonadotropin-releasing hormone agonist with recombinant-human growth hormone (GH) on the final height of girls with isolated GH deficiency: results from a controlled study.

To assess whether delaying puberty may improve final height in GH-deficient children with a poor height prediction at early puberty, we studied 24 girls with isolated GH deficiency until they reached their final height, in a controlled trial. Patients were taking recombinant human GH (r-hGH) substitutive therapy from 2.1 +/- 0.5 yr (0.1 IU/kg.day sc) before entering the study, without showing any improvement in height prediction (149.6 +/- 2.9 vs.150.3 +/- 2.2 cm) on entering puberty. Fourteen girls agreed to add a GnRH agonist (GnRHa) to r-hGH, whereas the remaining 10 decided against it and served as controls. At the start of the study, girls treated with or without GnRHa had similar auxological characteristics (bone age, 10.9 +/- 0.6 vs. 10.7 +/- 1.3 yr; height SD score for chronological age, -1.87 +/- 0.3 vs. -1.82 +/- 0.2), including pubertal development. The GnRHa (long-acting D-Trp-6-GnRH) was given at 60 microg/kg im every 28 days for 1.9 +/- 0.9 yr, then patients continued the r-hGH at the same dosage (3.1 +/- 0.7 yr). At the end of the study, bone age was 16.2 +/- 0.3 yr in GnRHa-treated girls and 16.6 +/- 0.9 yr in controls. Bone maturation was significantly slower during GnRHa (1.4 +/- 0.2 yr), and height SD score for bone age improved (-0.31 +/- 0.3) in comparison with controls (2.6 +/- 0.4 yr and -1.35 +/- 0.3 SD score; P < 0.001 and P < 0.0001, respectively). As a result, girls given the combined therapy reached a final height higher than that of controls (height SD score, -0.39 +/- 0.5 vs. -1.45 +/- 0.2; P < 0.0001) and also higher than their midparental height (-1.1 +/- 0.5; P < 0.0005). Controls reached their midparental height. In conclusion, our results demonstrate that slowing pubertal development with the administration of GnRHa for a limited time may improve final height in GH-deficient girls selected because of a poor height prediction at early puberty.

Body Height↗

PubMed2000

Brief report: disseminated mycobacteriosis caused by drug-resistant Mycobacterium triplex in a human immunodeficiency virus-infected patient during highly active antiretroviral therapy.

Mycobacterium triplex is a novel species that, until now, has been isolated only from limited clinical samples, and its clinical relevance has been largely unknown. In this report, we describe the first case of disseminated disease caused by M. triplex in a human immunodeficiency virus-infected patient.

AIDS-Related Opportunistic Infections↗

PubMed2000

Is there a place for combined therapy with GnRH agonist plus growth hormone in improving final height in short statured children?

The availability of recombinant human growth hormone (GH) and the optimization of substitutive therapy have improved final growth in children with GH deficiency, but despite this some of them fail to grow to their genetic potential. In particular, this may occur in patients who started the substitutive therapy too late and/or in whom bone age progressed too fast during GH administration. In these patients, with unfavorable auxological characteristics, the administration of a GnRH agonist in combination with GH may slow down bone maturation and prolong prepubertal growth, mimicking, to some extent, the growth pattern of patients with GH + Gn deficiency who grow better than children with isolated GHD. A different condition in which such a combined therapy might be used is the short normal child. As they are short but normally-growing children, the onset of puberty is in general appropriate for their chronological age but precocious for their height age. Thus, slowing down pubertal maturation may increase the time available for growth. GH would sustain growth during both GnRHa administration and after its withdrawal, when puberty starts again. Our preliminary results suggest that the administration of GH + GnRHa in combination may have a positive effect on final height in selected children with isolated GHD and in short normal children.

Body Height↗

PubMed1999

Mucus of the human olfactory epithelium contains the insulin-like growth factor-I system which is altered in some neurodegenerative diseases.

Growth factors are believed to be involved in the mitotic regulation of the animal olfactory epithelium (OE). We investigated mucus covering the human OE area to see if it contained the insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBPs) and to examine their behaviour in neurodegenerative diseases. Thirty patients with idiopathic late onset cerebellar ataxia (ILOCA), Parkinson's disease, and amyotrophic lateral sclerosis (ALS) and 30 age- and sex-matched healthy subjects were studied. In 10 controls, we also analyzed the mucus of the respiratory mucosa of the nose and tears. We detected IGF-I in the mucus covering the OE and Western ligand blot analysis (WLB) showed IGFBPs with an apparent Mr of 41, 500/38,500, 34,000 and 24,000, which were immunoprecipitated by specific antisera to IGFBP-3, -2 and -4, respectively. Their levels were higher than those observed in the respiratory mucosa of the nose or in tears. Mucus of the OE of the patients contained significantly reduced levels of IGF-I in comparison with those of controls. The intensity of all the IGFBPs-related bands were reduced in the ILOCA, while the remaining patients had a loss in the amounts of IGFBP-3. Plasma IGF-I and IGFBPs levels were similar in patients and controls. In conclusion, our data show that mucus covering the human OE contains IGF-I and IGFBPs, suggesting that these factors have a role in the activity of the OE. The amounts are reduced in the patients' mucus, possibly reflecting a dysfunction of the OE itself.

Amyotrophic Lateral Sclerosis↗

PubMed1999

Mononuclear cell reactivity to food allergens in neonates, children and adults.

A model of antigen-specific T-cell proliferative responses based on reciprocal patterns of responses to dietary and inhalant allergens has been suggested, the former being frequent in infancy but rare in adults, whereas the latter are preserved and expand between infancy and adulthood. We have evaluated the age-related variations of mononuclear cell reactivity to food allergens. The cord blood mononuclear cells (CBMC) of 30 neonates without family history of atopy and the peripheral blood mononuclear cells (PBMC) of 20 healthy children and of 40 healthy adults were stimulated in vitro with beta-lactoglobulin (BLG) or ovalbumin (OVA) and the cultures were harvested after 7 days. Neonates, children and adults were compared for the percentages of positive responses and for the magnitude of response. Adult subjects showed significantly lower percentages of positive responses and reduced magnitude of response than those observed in neonates and children either in BLG or in OVA cultures. We have not observed a decrease of food allergen mononuclear cell reactivity between neonates and children for the frequency of positive responses. The magnitude of response of neonates was significantly lower than that of children in BLG cultures. Our results seem to confirm the loss of mononuclear cell reactivity to food allergens in adult age. However, other reports show conflicting data. We suggest that a rigorous standardization of the methodological steps of in vitro mononuclear cell stimulation with allergen is necessary.

Adult↗

PubMed1999

Vitamin-D receptor genotype does not predict bone mineral density, bone turnover, and growth in prepubertal children.

We examined whether the polymorphism for BsmI restriction enzyme in the vitamin-D receptor (VDR) gene influenced radial (distal third) and lumbar (L2-L4) bone mineral density (BMD), phospho-calcium metabolism (calcium, phosphate, intact parathyroid hormone, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D), biochemical markers of bone formation (osteocalcin and carboxy-terminal propeptide of type-I procollagen) and bone resorption (carboxy-terminal telopeptide of type-I collagen and urinary cross-linked N-telopeptides of type I collagen), insulin-like growth factor I and insulin-like growth factor-binding protein 3, and growth in 209 healthy prepubertal children (112 males and 97 females) aged 7.1-10.0 years. Genotype frequencies were BB 19%, Bb 46%, and bb 35% in the pooled group of children. Clinical findings, dietary calcium intake, calcium density, and physical activity rate were not different (p NS) among the VDR genotypes. Radial BMD, lumbar BMDarea and lumbar BMD adjusted for the apparent bone volume (BMDvolume), and all the biochemical parameters did not differ (p NS) in relation to the VDR genotype. In conclusion, our data show that polymorphism for BsmI restriction enzyme in the VDR gene is not associated with radial and lumbar BMD, parameters of phospho-calcium metabolism and bone turnover, growth hormone-dependent growth factors, and growth in prepubertal children.

Alleles↗

PubMed1999

Management of puberty in growth hormone deficient children.

The pubertal growth spurt accounts for approximately one-eighth of adult height and is regulated by complex hormonal interactions involving the somatotropic and gonadal axes. The observation that children with growth hormone deficiency (GHD) may fail to achieve an appropriate pubertal growth spurt led to the development of strategies to optimize GH therapy during puberty. In one strategy the dosage of GH is increased during puberty to support pubertal growth and in keeping with the physiological increase in serum levels of the hormone seen at that age. A different approach is to combine a GnRH analog (GnRHa) to GH to stop pubertal development, delaying epiphyseal fusion and prolonging peripubertal growth. Both strategies require caution. As regards the first strategy, too high doses of GH may shorten the pubertal time for growth; we found a small, nonsignificant, improvement in final height by increasing the dose by less than half. Preliminary results on the second strategy are more encouraging. However, manipulation of puberty should be limited to selected patients who show a statural height SDS for bone age unfavorable in terms of height prognosis.

Adolescent↗

PubMed1998

Altered bone mineral density in patients with complete androgen insensitivity syndrome.

Androgens have major influences on the regulation of bone mineralization. Because of their unique peripheral metabolism androgens may act on bone via activation of the androgen and/or estrogen receptor. Patients with complete androgen insensitivity syndrome (cAIS) are natural models to assess androgen actions on bone. We studied bone mineral density (BMD) in 10 patients with cAIS (mean age 13.70, range 4.7-19.8 years); 3 patients were studied before gonadectomy; the others were castrated and 6 were on hormonal replacement therapy. The BMD area (aBMD) was measured by dual energy X-ray; lumbar 'apparent' volumetric density (vBMD) was calculated using the formula vBMD = aBMD x [4/(pi x width)]. In the patients, aBMD (0.72 +/- 0.16 g/cm2) and vBMD (0.23 +/- 0.04 g/cm3) were significantly (p < 0.001) reduced in comparison with those of a control group (n = 15, age 5.0-20.5 years: aBMD 1.028 +/- 0.20 g/cm2; vBMD 0.35 +/- 0.04 g/cm3). Both aBMD and vBMD were also reduced in comparison with normal values for males (aBMD -2.66 +/- 0. 99 SDS, p < 0.001; vBMD -3.08 +/- 1.53 SDS, p < 0.0005) and females (aBMD -2.88 +/- 1.05 SDS, p < 0.001; vBMD -2.84 +/- 1.18 SDS, p < 0. 0007). Real lumbar bone density, assessed by computed tomography in 1 patient, was also reduced (-6.2 SDS and -3.5 SDS for male and female normal values, respectively). Biochemical markers of bone metabolism were normal and not significantly different in patients and controls. Girls with cAIS did not have more fractures than controls. In conclusion, both aBMD and vBMD are reduced in cAIS patients, while bone turnover and the fracture risk seem not to be increased. Our data indicate that both androgens and estrogens may be required for acquisition of bone density during childhood.

Absorptiometry, Photon↗