PET/CT FAPI: Procedure and evidence review in oncology

Neoplasms are composed of malignant tumor cells, which are surrounded by other non-tumor cellular elements, in what has been defined as the microenvironment or tumor stroma. Evidence on the importance of the tumor microenvironment has not stopped growing in recent years. It plays a central role in cell proliferation, tissue invasion, angiogenesis and cell migration. The paradigm is the family of new FAPI radiopharmaceuticals that show the density of the fibroblast activation protein (FAP) which is overexpressed in the cell membrane of activated cancer-associated fibroblasts (CAF), and its presence is related to poor prognosis. This educational document includes the procedure for performing PET/CT FAPI, biodistribution and the main potentially clinical applications in oncology to date.

Impact of acute psychosocial stress on attentional control in humans. A study of evoked potentials and pupillary response

Psychosocial stress has increased considerably in our modern lifestyle, affecting global mental health. Deficits in attentional control are cardinal features of stress disorders and pathological anxiety. Studies suggest that changes in the locus coeruleus-norepinephrine system could underlie the effects of stress on top-down attentional control. However, the impact of psychosocial stress on attentional processes and its underlying neural mechanisms are poorly understood. This study aims to investigate the effect of psychosocial stress on attentional processing and brain signatures. Evoked potentials and pupillary activity related to the oddball auditory paradigm were recorded before and after applying the Montreal Imaging Stress Task (MIST). Electrocardiogram (ECG), salivary cortisol, and subjective anxiety/stress levels were measured at different experimental periods. The control group experienced the same physical and cognitive effort but without the psychosocial stress component. The results showed that stressed subjects exhibited decreased P3a and P3b amplitude, pupil phasic response, and correct responses. On the other hand, they displayed an increase in Mismatch Negativity (MMN). N1 amplitude after MIST only decreased in the control group. We found that differences in P3b amplitude between the first and second oddball were significantly correlated with pupillary dilation and salivary cortisol levels. Our results suggest that under social-evaluative threat, basal activity of the coeruleus-norepinephrine system increases, enhancing alertness and decreasing voluntary attentional resources for the cognitive task. These findings contribute to understanding the neurobiological basis of attentional changes in pathologies associated with chronic psychosocial stress.

Partial hardware removal in guided growth surgery: A convenient strategy?

BACKGROUND

Tension band plates (TPBs) are frequently used in guided growth (CG) surgeries. Recently, the concept of removing the metaphyseal screw only to stop the growth modulating effect rather than completely removing the implant, has gained popularity. Although this strategy would have certain potential advantages, the associated risks are unknown. The aim of this study is to report the experience of three institutions with this strategy.

METHODS

A database was compiled with the demographic information of patients treated by guided growth using TBPs between January 2014 and January 2019 at three institutions. The cases where only the metaphyseal screw was removed were identified. The records were reviewed to analyze the indications, demographic data, characteristics of the procedure, complications and need for additional procedures.

RESULTS

We reviewed 28 partial hardware removals, performed in 10 patients (all male). Initial surgery was indicated for angular deformity (N = 6), and leg-length discrepancy (N = 4). The average age at the time of surgery was 9.5 ± 2.9 years (range 4 to 13 years). Three procedures were performed on the distal femur, 3 on the proximal tibia, 2 on the distal tibia, and 20 combined. The average follow-up was 23.3 ± 11 months (range 12 to 52 months). We observed recurrence of deformities in 7 of 28 (22%) limbs that required re-insertion of the metaphyseal screw. Two patients presented complications from the procedure: soft tissue irritation (N = 1) and angular deformity (N = 1). Both patients required unplanned surgery.

DISCUSSION

Partial hardware removal in guided growth surgery could favor the presentation of complications. The benefits of this strategy must be considered against the possible undesired effects generated by its application.

STUDY DESIGN

Therapeutic study (Level IV).

Importance of 68Ga-PSMA PET/CT in hospital practice. View of the radiation oncologist

Radiotherapy is a treatment with curative intent, both in patients with primary diagnosis of prostate cancer (PCa) and in patients presenting with biochemical recurrence after radical prostatectomy (RP). Moreover, the use of stereotactic body radiotherapy as a metastasis directed therapy in patients with oligometastatic PCa has significantly increased in the recent years. Conventional imaging techniques, including transrectal ultrasound, computed tomography (CT), morphologic magnetic resonance and bone scintigraphy have traditionally played a minor role in all those clinical scenarios due to its low diagnostic accuracy. The recent development of the positron emission tomography (PET) radiotracer ⁶⁸Ga-PSMA binding to the prostate specific membrane antigen (PSMA), a transmembrane glycoprotein overexpressed in PCa cells, has shown promising results. Detection rates for PCa lesions are higher than CT and higher than the best technique available, the PET/CT with choline. Its superiority has been demonstrated even at very low PSA levels (<1 ng/ml). This increase in diagnostic accuracy represents a potential impact on patient management, especially in radiotherapy. Even if this imaging technique is already available for routine clinical practice in some European countries, in Spain, unfortunately, there is very limited access. In this review, we analyze the main studies that investigate the usefulness of ⁶⁸Ga-PSMA PET/CT in patients with PCa and its potential impact on radiotherapy treatments. In addition, we compared the ⁶⁸Ga-PSMA PET/CT, with the multiparametric magnetic resonance imaging and the PET/CT with choline, in the different clinical scenarios.

Photoprotection and photoreception of intraocular lenses under xenon and white LED illumination

OBJECTIVE

To analyze the photoprotection and phototransmission that various intraocular lenses (IOLs) provide under the illumination of a xenon (Xe) lamp and white LEDs (light emitting diode).

METHODS

The spectral transmission curves of six representative IOLs were measured using a Perkin-Elmer Lambda 35 UV/VIS spectrometer. Various filtering simulations were performed using a Xe lamp and white LEDs. The spectral emissions of these lamps were measured with an ILT-950 spectroradiometer.

RESULTS

The IOLs analyzed primarily show transmission of nearly 100% in the visible spectrum. In the ultraviolet (UV) region, the filters incorporated in the various IOLs did not filter equally, and some of them let an appreciable amount of UV through. The Xe lamp presented a strong emission of ultraviolet A (UVA), and its emission under 300nm was not negligible. The white LED did not present an appreciable emission under 380nm.

CONCLUSIONS

The cut-off wavelength of most filters is between 380 and 400nm (Physiol Hydriol60C(®), IOLTECH E4T(®), Alcon SA60AT(®), Alcon IQ SN60WF(®)), so that their UV protection is very effective. Nonetheless, the IOL OPHTEC Oculaid(®) contains a filter that, when a Xe lamp is used, lets through up to 20% for 350nm and up to 15% for 300nm, which at this point is ultraviolet B (UVB). The OPHTEC(®) Artisan IOL has a transmission peak below 300nm, which must be taken into account under Xe illumination. White LEDs do not emit energy below 380nm, so no special protection is required in the UV region.

Spectral transmission of the pig lens: effect of ultraviolet A+B radiation

OBJECTIVE

To determine the spectral transmission curve of the crystalline lens of the pig. To analyse how this curve changes when the crystalline lens is irradiated with ultraviolet A+B radiation similar to that of the sun. To compare these results with literature data from the human crystalline lens.

PROCEDURES

We used crystalline lenses of the common pig from a slaughterhouse, i.e. genetically similar pigs, fed with the same diet, and slaughtered at six months old. Spectral transmission was measured with a Perkin-Elmer Lambda 35 UV/VIS spectrometer. The lenses were irradiated using an Asahi Spectra Lax-C100 ultraviolet source, which made it possible to select the spectral emission band as well as the intensity and exposure time.

RESULTS

The pig lens transmits all the visible spectrum (95%) and lets part of the ultraviolet A through (15%). Exposure to acute UV (A+B) irradiation causes a decrease in its transmission as the intensity or exposure time increases: this decrease is considerable in the UV region.

CONCLUSIONS

We were able to determine the mean spectral transmission curve of the pig lens. It appears to be similar to that of the human lens in the visible spectrum, but different in the ultraviolet. Pig lens transmission is reduced by UV (A+B) irradiation and its transmission in the UV region can even disappear as the intensity or exposure time increases. An adequate exposure intensity and time of UV (A+B) radiation always causes an anterior subcapsular cataract (ASC).

Ultraviolet radiation at Mediterranean latitudes and protection efficacy of intraocular lenses

PURPOSE

After determining the mean intensity of ultraviolet radiation to which the human eye is exposed at Mediterranean latitudes, this data is used to evaluate the efficacy of the ultraviolet filters incorporated into various intraocular lenses.

METHODS

Ultraviolet radiation measured at Mediterranean latitudes was used as a reference for the theoretical calculation of the amount of radiation to which the human eye is exposed. The spectral transmission curve from 290 to 380 nm was measured for 10 IOLs using a UV/VIS Perkins-Elmer Lambda 800 spectrometer.

RESULTS

At Mediterranean latitudes, at sea level, with a mean annual solar irradiation of 50 j/cm(2), the human eye receives a quantity of UVA and UVB that is lower than the threshold toxic dose for the rabbit crystalline lens (93 j/cm(2) for UVA and 6.45 j/cm(2) for UVB). However, at higher altitudes and with albedo approaching 0.9 (fresh snow), the amount of radiation increases, with duration of exposure potentially playing a significant role. The UV filters incorporated into the IOLs studied are, in general, protective against such levels of radiation.

CONCLUSION

At Mediterranean latitudes, at sea level, the amount of UV radiation to which our eyes are exposed is insufficient to damage the crystalline lens; however, at higher altitudes, the risk of such damage exists. UV filters incorporated into intraocular lenses are generally effective, since they filter all radiation with wavelengths under 380 nm.

Cardiac sympathetic impairment parallels nigrostriatal degeneration in Probable Dementia with Lewy Bodies

AIM

Dementia with Lewy Bodies (DLB) must be distinguished from other types of dementia because of important differences in patient management and outcome. Both reduction in cardiac 123I-metaiodobenzilguanidine (MIBG) uptake and decreased 123I-FP-CIT binding in basal ganglia have been described in DLB. The aim of this study was to assess the relationship between cardiac sympathetic activity and nigrostriatal degeneration in patients with probable DLB.

METHODS

Twenty-eight patients (15 males; mean age 77 years, range 64-88 years) with clinical international criteria of probable DLB were included in the study. All patients underwent a cardiac MIBG scintigraphy and a FP-CIT SPECT. Global cardiac MIBG uptake was semiquantified by means of heart-to-mediastinum ratio (HMR) (normal >1.56). FP-CIT binding in basal ganglia was calculated and compared with an age-matched control group. The relation between cardiac MIBG uptake and FP-CIT uptake in basal ganglia, and the relationship of these two techniques with distinctive symptoms of DLB, features of past medical history and data from the neuropsychological examination were assessed.

RESULTS

Cardiac MIBG uptake was decreased in 23 of 28 patients (HMR=1.32, range 0.95-1.85). The FP-CIT binding in basal ganglia was significantly lower than in control group (2.01±0.5 vs 2.62±0.2, P<0.05). All patients with reduced cardiac HMR showed decreased FP-CIT binding in basal ganglia. There was a positive correlation between the HMR and specific binding ratio of striatum (P<0.01). A high correlation between FP-CIT SPECT and the presence of parkinsonism also was found. No correlation between cardiac MIBG uptake and demographic, clinical or neuropsychological data was found.

CONCLUSION

In probable DLB cardiac MIBG uptake and FP-CIT binding in basal ganglia are reduced. The positive correlation between both measures suggests that cardiac sympathetic degeneration and nigrostriatal degeneration parallel similarly in patients with probable DLB.

Identification of viral pathogens in aborted fetuses and stillborn piglets from cases of swine reproductive failure in Spain

The objective of the present study was to determine the presence of recognised abortifacient viruses such as porcine reproductive and respiratory virus (PRRSV), Aujeszky's disease virus (ADV), porcine parvovirus (PPV) and porcine circovirus type 2 (PCV2), in tissues from aborted fetuses and stillborn neonates in cases of late reproductive failure in swine. A total of 293 specimens (fetuses aborted in the last third of gestation and stillborn piglets) from 100 different cases of late-term abortions and premature farrowing from 15 different Spanish provinces were studied. PRRSV was detected in 9/100 cases by RT-PCR. Only 1/100 cases analysed (corresponding to a late-term aborted fetus with a negative PRRSV RT-PCR result) was positive for PCV2 by PCR. Neither ADV (monitored by viral isolation plus antigen detection) nor PPV (monitored by ELISA antigen capture test) infection was identified. The results suggest that PRRSV is one of the most important infectious agents, if not the most relevant one, associated with fetal infection leading to abortion or premature farrowing in Spain. Moreover, other viral pathogens such as ADV, PPV and PCV2 seem to have a minor impact on reproductive disease.

Incidence of incisional hernia following vertical banded gastroplasty

BACKGROUND

Our aim was to determine which patient-related factors influence the incidence of incisional hernia after vertical banded gastroplasty for morbid obesity.

METHODS

We reviewed the medical records of 80 morbidly obese patients operated on between 1986 and 1993. All the operations were performed by only one surgeon, and the midline laparotomy was closed by means of continuous polyglactin 910 suture. Statistical analysis was performed using the Fisher exact test, and significance was assigned for values of P<0.05.

RESULTS

Incidence of incisional hernia in: obese 24%, superobese 51% ( P=0.0165), men 40%, women 34% ( P=0.7671), age<50 33%, age>50 50% ( P=0.3137), nondiabetics 31%, diabetics 66% ( P=0.0610), no wound infection 34%, wound infection 37% ( P>0.9999), no anemia 31%, anemia 50% ( P=0.1675), no vomiting 39%, vomiting 32% ( P=0.6350).

CONCLUSION

The only patient-related factor that significantly influences the incidence of incisional hernia in morbidly obese patients is body mass index.

[Rheumatoid arthritis among mapuche aborigines. A 16 years experience in the IX Region of the Chile]

BACKGROUND

Mapuche, Chilean natives, represent approximately 9.8% of Chilean population and in the IX region of the country, they account for 18.4% of population over 15 years old. They preserve some socio-cultural characteristics that make them different to the rest of the population.

AIM

To describe the epidemiological characteristics rheumatoid arthritis among Mapuche natives.

SUBJECTS AND METHODS

Retrospective review of patients of Mapuche origin with rheumatoid arthritis, seen at Temuco Hospital between 1980 and 1996.

RESULTS

Among 308 cases gathered, only 106 (93 women, aged 55 +/- 10 years old) complied with 1987 American College of Rheumatology (ACR) criteria for rheumatoid arthritis. The disease began between 29 and 52 years old in 73% of patients and the mean delay in diagnosis was 4.4 years. At diagnosis, 99% had symmetric poliarthritis, 28.3% had either fatigue, fever or weight loss, and 46.9% were in class III or in class IV of ACR-1991. Fifty three percent of patients developed Sicca syndrome, 36% developed nodules, 23% developed Raynaud phenomenon, 11% developed pulmonary involvement, 7% developed vasculitis, 5% developed neurological manifestations and 19% developed ophthalmologic involvement. Rheumatoid factor was positive in 78% and 73% had erosions. HLA DR4 was (+) in 60% of 30 patients. Thirty percent required 3 or more disease modifying drugs and prednisone over 10 mg/day. There was no correlation between functional capacity and several other features of the disease.

CONCLUSIONS

Mapuche rheumatoid arthritis patients are detected late and have a poor functional capacity at the time of diagnosis. They also have a higher proportion of extraarticular manifestations, more erosions and require more aggressive treatments.

Effectiveness of doxycycline in the prevention of an experimental infection with Actinobacillus pleuropneumoniae in pigs

The effectiveness of medication with doxycycline in feed in the control of pleuropneumonia in pigs was tested using an Actinobacillus pleuropneumoniae serotype 1 aerosol challenge model. Two groups of 10 animals were used for the challenge, a 'medicated group' and an 'unmedicated group'. A third group of four animals was used as a 'control group'. Pigs from the medicated group were provided with feed containing 250 p.p.m. doxycycline (HIPRAMIX/DOXI) for 8 consecutive days and were challenged on the fifth day of treatment. No clinical signs were observed in pigs from the 'control group'. Four animals from the 'unmedicated group' died within the first 48 h after challenge with clinical and lesional evidence of an acute form of pleuropneumonia. Clinical signs of animals surviving the first 48 h were progressively less severe and showed lesions similar to those described for subacute-chronic forms of the disease. However, only one animal from the 'medicated group' showed clinical signs of a chronic form of pleuropneumonia. Reisolation of A. pleuropneumoniae was more evident from lung tissues of animals fed the doxycycline-free feed (70%), coinciding with the presence of both acute and subacute lesions. However, the micro-organism could be reisolated from only one animal which belonged to the 'medicated group'. It is concluded that the treatment of pigs with 250 p.p.m. doxycycline (HIPRAMIX/DOXI) prevents disease caused by A. pleuropneumoniae.

Prevalence of Haemophilus parasuis serovars isolated in Spain from 1993 to 1997

From 1993 to 1997, 327 strains of Haemophilus parasuis were isolated from spanish swine in our Diagnostic Laboratory and 174 strains (53.2%) were serotyped. Four serotypes, sv. 5 (18.4%), sv 4 (16%), sv. 2 (9.2%) and sv. 13 (8%) were the most frequently isolated and 29.3% of the studied strains were classified as non typable. The results obtained indicate that the distribution of the serotypes in Spain is very similar to that found by other researchers in Germany, Australia, Canada and alike to that found in the United States.

Methylenetetrahydrofolate reductase polymorphism, dietary interactions, and risk of colorectal cancer

Folate derivatives are important in experimental colorectal carcinogenesis; low folate intake, particularly with substantial alcohol intake, is associated with increased risk. The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate, required for purine and thymidine syntheses, to 5-methyltetrahydrofolate, the primary circulatory form of folate necessary for methionine synthesis. A common mutation (677C-->T) in MTHFR reduces enzyme activity, leading to lower levels of 5-methyltetrahydrofolate. To evaluate the role of folate metabolism in human carcinogenesis, we examined the associations of MTHFR mutation, plasma folate levels, and their interaction with risk of colon cancer. We also examined the interaction between genotype and alcohol intake. We used a nested case-control design within the Physicians' Health Study. Participants were ages 40-84 at baseline when alcohol intake was ascertained and blood samples were drawn. During 12 years of follow-up, we identified 202 colorectal cancer cases and matched them to 326 cancer-free controls by age and smoking status. We genotyped for the MTHFR polymorphism and measured plasma folate levels. Men with the homozygous mutation (15% in controls) had half the risk of colorectal cancer [odds ratio (OR), 0.49; 95% confidence interval (CI), 0.27-0.87] compared with the homozygous normal or heterozygous genotypes. Overall, we observed a marginal significant increased risk of colorectal cancer (OR, 1.78; 95% CI, 0.93-3.42) among those whose plasma folate levels indicated deficiency (<3 ng/ml) compared with men with adequate folate levels. Among men with adequate folate levels, we observed a 3-fold decrease in risk (OR, 0.32; 95% CI, 0.15-0.68) among men with the homozygous mutation compared with those with the homozygous normal or heterozygous genotypes. However, the protection due to the mutation was absent in men with folate deficiency. In men with the homozygous normal genotype who drank little or no alcohol as reference, those with the homozygous mutation who drank little or no alcohol had an 8-fold decrease in risk (OR, 0.12; 95% CI, 0.03-0.57), and for moderate drinkers, a 2-fold decrease in risk (OR, 0.42; 95% CI, 0.15-1.20); no decrease in risk was seen in those drinking 1 or more drinks/day. Our findings provide support for an important role of folate metabolism in colon carcinogenesis. In particular, these results suggest that the 677C-->IT mutation in MTHFR reduces colon cancer risk, perhaps by increasing 5,10-methylenetetrahydrofolate levels for DNA synthesis, but that low folate intake or high alcohol consumption may negate some of the protective effect.

Identification of a Mr 40,000 polypeptide from colorectal cancer which expresses organ-specific cancer neoantigen activity as determined by leukocyte adherence inhibition

Human cancers express organ-specific neoantigens (OSNs) that elicit immune responses in the tumor host. Leukocyte adherence inhibition, an in vitro assay that detects the antitumor immunity, was used to monitor the purification of the OSN from serum-free spent medium of tissue-cultured colon cancer cell lines (HCT-15 and SW-620). A monoclonal antibody (anti-p40) directed to a cross-reactive framework determinant of Mr 40,000 (p40) cell surface polypeptide, which was a principal component of the enriched isolate with OSN activity, was used to monitor the purification of p40 by enzyme-linked immunosorbant assay. About 50 liters of spent medium were generated from 20 m2 of cells, collected, concentrated, and then separated by anion exchange, molecular-sieve, and blue-Sepharose affinity chromatography. OSN and p40 activity coisolated. p40 was then purified by monoclonal antibody anti-p40 affinity chromatography. The affinity-purified fraction was enriched for both p40 and leukocyte adherence inhibition activity that was specific for leukocytes from colon cancer patients in blind leukocyte adherence inhibition assays. When affinity-purified p40 from colon and lung cancers was tested blind in a criss-cross fashion with leukocytes from colon and lung cancer patients, the positive responses were to the appropriate p40. The homologous colon cancer p40 molecule showed size and considerable charge microheterogeneity (pI 6.3 to 7.6). Affinity-purified p40 and OSN coisolated on hydrophobic interaction and hydroxylapatite high-pressure liquid chromatography. Note that not all colon cancer OSN activity was bound by the anti-p40 affinity column. However, unbound OSN activity also eluted from hydrophobic interaction high-pressure liquid chromatography at the same time as affinity-purified p40, and residual p40 activity was detected by enzyme-linked immunosorbant assay. The results indicate that a p40 glycoprotein from the cell membrane of colon cancer cells coisolates with fractions having OSN activity. Impurities do not seem to account for the OSN activity. The OSN epitope on the Mr 40,000 molecule is recognized by leukocytes from colon cancer patients and is distinct from the cross-reactive framework determinant recognized by mouse monoclonal antibody anti-p40.