Limb Defects Research Articles

CHILD syndrome: A rare case report

CHILD syndrome is a rare unilateral icthyosiform naevus, characterized by congenital hemidysplasia with icthyosiform erythroderma and limb defect. It is inherited as X- linked dominant trait with lethality for male embryo. We report a case of 9-year-old female child with right sided patchy psoriasiform epidermal nevus and ipsilateral limb defect. The rarity of the syndrome prompted us to report this case.

Cutis marmorata telangiectatica congenita with limb defects, cleft palate, and ambiguous genitalia

Cutis marmorata telangiectatica congenita (CMTC) is an uncommon, congenital, vascular malformation first described by van Lohuizen in 1922. CMTC is an infrequently reported congenital cutaneous disorder and is usually present at birth but can appear up to 3 months to 2 years of age. Hereby, we report a case of a 2-day-old infant with CMTC involving trunk with rarely reported congenital anomaly involving multiple system, i.e., musculoskeletal, cardiovascular, pulmonary, ophthalmic, excretory, oropharyngeal, and reproductive system.

A Case of VACTERL Association Complicated with Multiple Rib Abnormalities

VACTERL association is an acronym that includes vertebral anomalies (V), anal atresia (A), cardiac defects (C), tracheoesophageal fistula (TEF) or esophageal atresia (EA), renal anomalies (R), and limb defects (L). Rib abnormalities have rarely been reported with the VACTERL association. The second case of VACTERL association complicated with multiple rib abnormalities will be reported in this case report. A 4-year-old girl who had been diagnosed with congenital cardiovascular disease and received surgical corrections soon after birth consulted our institution by complaining congenital scoliosis. The little girl was diagnosed with VACTERL association (congenital cardiovascular disease, scoliosis with hemivertebra and butterfly vertebra, and nephrolithiasis) and congenital multiple rib abnormalities. The Cobb angle of the main curve was 29.3° before surgery, 19.9° after surgery, and 23° at last follow-up. Multiple rib abnormalities may be seen in the VACTERL association. Clinicians should have a high index of suspicion when evaluating patients with rib abnormalities associated with VACTERL. It is extremely necessary for careful physical examination and detailed auxiliary examination to each system (including echocardiography, computed tomography, magnetic resonance imaging, and so on) when diagnosing VACTERL association. Also, recognizing and understanding the congenital multiple system malformation is important, which aids in the diagnosis of disease and accordingly plan the therapeutic interventions. Early diagnosis of congenital scoliosis with appropriate surgical intervention decreases long-term morbidity.

Microbiological Causes Of Defects In Fetal Development And Miscarriage

Abstract During pregnancy many agents can be teratogenic i.e. can be dangerous for embryo or fetus and cause differentiated adverse effects. Teratogenic agents include substances (e.g. many pharmaceuticals, mycotoxins – e.g. aflatoxins and ochratoxin A), radiation (e.g. X/RTG, γ) and infectious agents. The latter include bacteria (e.g. Listeria monocytogenes, Treponema pallidum), protozoa (e.g. Toxoplasma gondii) and viruses (e.g. ZIKV, parvovirus B19, herpesviruses: CMV, HSV, VZV). Quite a few pathogens can be vertically transmitted, i.e. through placenta (poorly understood mechanism), but not all are typical teratogenic agents (TORCH group). Infection during gestation can be oligosymptomatic or asymptomatic for the mother, nevertheless can also be fatal for the child, causing among others IUGR, SNHL, malformation (e.g. microcephaly, limb defects), abortion. Some (but not all) of these abnormalities can be non-invasively diagnosed by ultrasonography (USG) and prevented by vaccination (in case of the rubella and varicella). In some countries routine serological diagnostics for selected pathogens are performed during pregnancy. Generally transplacental transmission occur mostly during initial (primary) infection and are most dangerous during the first and second trimester (intensive morphogenesis and organogenesis). Conversely chance of fetus infection usually increases with time and is highest in the third trimester. 1. Introduction. 2. Placenta. 3. Preterm delivery and vaginosis. 4. TORCH group. 5. Teratogenic microorganisms and viruses. 5.1. Bacteria. 5.2. Protozoa. 5.3. Viruses. 6. Mycotoxins. 6.1. Description of selected mycotoxins. 7. Summary

Reconstruction of Defects of the Lower Third of the Leg and Foot With a Reverse Sural Island Flap

Background: Closure of lower limb defects asks for thorough knowledge of all the reconstructive options, starting with the use of local tissues. The scarce availability of such, makes this task difficult and demanding. Unique nature of blood supply to the leg, complicates this issue even more. Reverse sural island flap is what we found handy in solving the problem for defects of small to moderate size, on the lower leg and foot. Objectives: The aim of this study is to report our experience with the use of the reverse sural island flap in the reconstruction of complex soft tissue defects of the lower leg and the foot. Materials and methods: Following institutional review board approval, a database search was completed to identify all patients who underwent reconstruction of distal lower extremity and foot defects with a reverse sural island flap between 2011-2019. Data were collected from the medical records of patients, as regards: demographics, history of trauma or nature of the wound, personal medical history (accompanying diseases, smoking status), location of the defect, dimensions of the flap after being elevated, pedicle length etc. Results: 15 cases received a reverse sural island flap, all the cases except one, being acute trauma. The remaining one was a chronic wound after a previous burn. In one of the cases the flap was delayed. In three of them flap it was used to cover defects of the dorsum of the foot. Flap dimension varied from 7 × 4 cm to 15 × 12 cm, length of the pedicle from 6 to 16 cm, two of the flaps were very close to the distal popliteal crease. In all of the cases, except one, donor area of the flap needed be skin grafted. Only two of the flaps were complicated: one by a partial necrosis, the other by a venous stasis, which in the end were both treated successfully. In none of the patients a detailed examination of vascular supply of the area was needed, all of them being nondiabetic and nonischemic legs. Conclusions: Reverse sural island flap is a very useful tool for the reconstruction of small to moderate defects of the lower leg and foot, relatively easy to be raised, with no special needs for complicated vascular preoperative workup, and with a low rate of failure and complications in carefully selected patients.

3D-CTA assisted anterolateral thigh lobulated perforator flap in repairing soft tissue defect of limb: 11 cases report

Objective To investigate the effectiveness of preoperative 3D-CTA in assisting the preparation of free thinned anterolateral thigh lobulated perforator flap with nerve in repairing soft tissue defect of limb. Methods Between February, 2010 and May, 2018, free super-thin anterolateral thigh lobulated perforator flap with nerve was transferred to repair soft tissue defect of limbs in 11 cases. There were 8 males and 3 females with an average age of 35 (range, 22-56) years. The defect area was 8.0 cm×11.0 cm-9.0 cm×23.0 cm. Preoperation CT scan of the free flap donor site was performed to obtain 3D images of the region with arterial blood supply by digital 3D reconstruction CT, and to determine the origin, direction, classification, length, diameter and the position of pedicle perforator. Postoperative regular followed-up was carried according to the Upper Limb Function Evaluation Trial Standards of Chinese Medical Association of Hand Surgery and Enneking Evaluation System. Results All 11 flaps survived. No vascular crisis happened. All 11 cases were followed-up for 3 to 12 (average, 5) months. The flaps were supple and elastic with near normal color. There was no bulkiness. Sensory function was recovered well and two point discrimination was 3.0-6.0 mm. According to the Upper Limb Function Evaluation of Upper Limb of Chinese Medical Association of Hand Surgery, the results were excellent in 1 case, good in 3 cases and fair in 1 case. The Enneking system was used to assesse the lower limbs recovery. The average score was 21, an average of 70% of limb function restored. Conclusion The free super-thin anterolateral thigh lobulated perforator flap with nerve offers advantages to the traditional anterolateral thigh flap. The survived flaps are ideal in terms of covering limb defects and restoring functions. Preoperative 3D-CTA in the anterolateral thigh perforator flap transplantation is an accurate and useful method. It helps a safer and successful operation with optimal outcome. Key words: 3D-CTA; Anterolateral thigh perforator flap; Lobulated flap; Repair; Limb

Epidemiological study of congenital and hereditary anomalies in Sialkot District of Pakistan revealed a high incidence of limb and neurological disorders

Abstract Background Pakistan faces high incidence of congenital anomalies (CA) and hereditary anomalies due to various factors, including a high rate of consanguinity, early marriages, and predominance of extended families. There is a paucity of epidemiological studies that could provide a baseline for management strategies for these anomalies. Objectives We aimed to elucidate the pattern, as well as the clinical and genetic aspects, of CA prevalence among the general population in Sialkot District of Pakistan. Methods In a cross-sectional sampling design, subjects and families with a certain type of CA were recruited from hospitals and medical centers in Sialkot District. Subjects were also selected from various towns and remote villages by visiting public places. Phenotypic and descriptive data were obtained, pedigrees were constructed, and parental and demographic attributes were recorded. Results A total of 241 independent subjects and/or families with CA were recruited. The malformations were classified into five major and 56 minor categories. Limb defects had the highest representation (n = 113; proportion = 0.469; 95% confidence interval (CI) = 0.406–0.532), followed by neurological anomalies (n = 76; proportion = 0.315; 95% CI = 0.257–0.374). Among the limb defects, polydactyly and talipes were most prevalent while, among neurological disorders, intellectual disability and cerebral palsy were more frequent. In this cohort, sporadic occurrence was customary compared to the familial presentation (n = 144 vs 97). Analyses of various attributes, such as gender differences, parental consanguinity, and paternal ages, as well as pedigree analyses, revealed marked heterogeneity among the major and minor categories of CA. Conclusion The pattern of anomalies witnessed in this cohort and a high occurrence of sporadic cases point to a substantial role of nongenetic etiological factors, which could be minimized by strengthening the health-care system.

An audit of microvascular free tissue transfers for post-traumatic lower limb defects

An audit of microvascular free tissue transfers for post-traumatic lower limb defects

Application of anteromedial thigh perforator flap in repair of soft tissue defects of lower limbs

To investigate effectiveness of anteromedial thigh perforator flap in repair of soft tissue defects of lower limbs. Between January 2015 and October 2018, 7 patients with soft tissue defects of the lower limbs were repaired with the anteromedial thigh perforator flaps. The patients were males, aged 8-30 years (median, 23 years). There were 5 cases of traffic accident injuries (the time from injury to admission was 1-4 hours, with an average of 1.5 hours), 1 case of scar formation after traffic accident, and 1 case of scar deformity after burn. The defect located in calf in 5 cases, foot in 1 case, and thigh in 1 case. The area of soft tissue defects ranged from 12 cm×4 cm to 21 cm×7 cm; and the area of flaps ranged from 14 cm×5 cm to 24 cm×8 cm. The donor sites were sutured directly. The flaps survived completely after operation in 6 cases, and the wounds healed by the first intention; the partial necrosis of flap occurred and healed after skin graft repair in 1 case. One incision partially ruptured in the donor site and healed after dressing change; the other incisions healed by the first intetion. All patients were followed up 6 months to 2 years with an average of 9 months. Except 1 case complained of edema of the flap, the other patients had good shape, good color, and no swelling. For patients with soft tissue defects of lower limbs that cannot be repaired with anterolateral thigh perforator flap, the anteromedial thigh perforator flap can be used for good results.

A rare case report of Goltz syndrome and review of literature

A rare case report of Goltz syndrome and review of literature - IJCED- Print ISSN No: - 2581-4710 Online ISSN No:- 2581-4729 Article DOI No:- 10.18231/j.ijced.2019.075, IP Indian Journal of Clinical and Experimental Dermatology-IP Indian J Clin Exp Dermatol

The Clinical Application of Medial Sural Vessels as Recipient Vessels in Repairing Traumatic Tissue Defects in the Lower Limbs.

The use of medial sural vessels (MSVs) as recipient vessels to repair wounds in the lower limbs has been previously reported. However, there is controversy regarding the methods used to expose MSVs and the repairable area of the wound. Eight fresh cadavers were used to determine the shape, outer diameter, and length of the MSVs arising from the popliteal vessels. Lower extremity wounds were repaired in 7 patients using free latissimus dorsi flaps with the MSVs as recipient vessels. The flap area ranged from 18 × 11 cm to 24 × 17 cm, and the postoperative follow-up time ranged from 7 to 60 months. The outer diameter of the medial sural artery from the starting point of the popliteal artery was 2.48 ± 0.24 mm. After descending 29.98 ± 4.62 mm, the vessels entered the muscle; the outer diameter of the blood vessel upon entry was 2.24 ± 0.17 mm. Notably, the outer diameter of the vessel was 1.88 ± 0.09 mm only 2 cm after entering the muscle. Seven cases were treated clinically. In 6 cases, we used an approach between the medial head of the gastrocnemius muscle and the tibia to expose and anastomose the MSVs. In 1 case, the vascular diameter was mismatched. After surgery, the flap survived completely in 6 cases. The remaining case experienced epidermal necrosis in the distal part of the flap, which resolved spontaneously. There were no obvious complications. An approach between the medial head of the gastrocnemius muscle and the tibia can easily expose and anastomose the MSVs in a lateral position. Latissimus dorsi flaps were useful in repairing limb wounds as far as the talocrural region with the MSVs as the recipient vessels.

Risk of Stillbirth for Fetuses With Specific Birth Defects.

To estimate the risk of stillbirth (fetal death at 20 weeks of gestation or more) associated with specific birth defects. We identified a population-based retrospective cohort of neonates and fetuses with selected major birth defects and without known or strongly suspected chromosomal or single-gene disorders from active birth defects surveillance programs in nine states. Abstracted medical records were reviewed by clinical geneticists to confirm and classify all birth defects and birth defect patterns. We estimated risks of stillbirth specific to birth defects among pregnancies overall and among those with isolated birth defects; potential bias owing to elective termination was quantified. Of 19,170 eligible neonates and fetuses with birth defects, 17,224 were liveborn, 852 stillborn, and 672 electively terminated. Overall, stillbirth risks ranged from 11 per 1,000 fetuses with bladder exstrophy (95% CI 0-57) to 490 per 1,000 fetuses with limb-body-wall complex (95% CI 368-623). Among those with isolated birth defects not affecting major vital organs, elevated risks (per 1,000 fetuses) were observed for cleft lip with cleft palate (10; 95% CI 7-15), transverse limb deficiencies (26; 95% CI 16-39), longitudinal limb deficiencies (11; 95% CI 3-28), and limb defects due to amniotic bands (110; 95% CI 68-171). Quantified bias analysis suggests that failure to account for terminations may lead to up to fourfold underestimation of the observed risks of stillbirth for sacral agenesis (13/1,000; 95% CI 2-47), isolated spina bifida (24/1,000; 95% CI 17-34), and holoprosencephaly (30/1,000; 95% CI 10-68). Birth defect-specific stillbirth risk was high compared with the U.S. stillbirth risk (6/1,000 fetuses), even for isolated cases of oral clefts and limb defects; elective termination may appreciably bias some estimates. These data can inform clinical care and counseling after prenatal diagnosis.

АССОЦИАЦИЯ VACTERL (ОБЗОР ЛИТЕРАТУРЫ И КЛИНИЧЕСКИЙ СЛУЧАЙ)

В статье рассматривается диагностика, эпидемио­логия синдрома VATER (VACTERL), включающего мно­жественные пороки развития: дефекты развития позвоночника, пороки сосудов, атрезию ануса, тра­хео­пищеводный свищ и атрезию пищевода, аномалии лучевой кости и почек, а также пороки сердца и конечностей. Синдром встречается с частотой от 1:10000 до 1:40000 новорожденных. Отражены и подробно обсуждаются составляющие синдрома. Произведен разбор клинического случая сочетания синдрома VACTERL с агенезией правого легкого. Отмечен положительный эффект корригирующих оперативных вмешательств и реабилитационных мероприятий по поводу пороков, входящих в синдром VACTERL, однако состояние ребенка и прогноз в значительной степени обусловлены другим пороком – агенезией правого легкого.

Growing up with a rare genetic disease: an interpretative phenomenological analysis of living with Holt-Oram syndrome

Background Holt-Oram syndrome (HOS) is a rare genetic disease characterized by variable radial upper limb and cardiac defects. The aim of this research was to shed light on people’s subjective perceptions of their diseases, how these perceptions provide meaning, and the consequences the syndrome can have in daily life and across all life stages. Methods Semistructured interviews with ten participants diagnosed with HOS were conducted in France and analyzed using interpretative phenomenological analysis. Results Participants’ experiences fall under two main themes, namely, “stages of self-construction as different” and “when I am no longer the only one involved”, each of which has three subthemes. From childhood onwards, symptoms monopolize the physical and psychological spheres. The feeling of being different is unavoidable until the patient can appropriate his or her condition, and by the end of adolescence, the patient generally feels that he or she has adapted to the syndrome. In adulthood, other concerns arise, such as the fear of rejection, the need to better understand the genetic issues of the condition and the desire for offspring to not experience the same life difficulties. Conclusion The findings underscore the specific psychological issues associated with the syndrome at different life stages and the need for holistic genetic treatment with dedicated reference centers to improve care and further address these issues. IMPLICATIONS FOR REHABILITATION Holt-Oram syndrome is a genetic disease characterized by abnormalities of the upper limbs and shoulder girdle and associated with a congenital heart defect. Specific issues arise at different stages of life: the physical consequences of the syndrome arise during childhood, the self-construction of pervasive difference during adolescence, the fear of being rejected as a young adult, and concerns about future parenthood and the transmission of the syndrome and the desire that one’s child not be confronted with the same difficulties in adulthood. The complexity and entanglement of medical and existential issues related to HOS requires the development of multidisciplinary consultations that promote holistic care. The rarity of the syndrome and the lack of knowledge about HOS among health professionals and the general public make it necessary both to establish reference centers and to create patient associations to support patients.

Septo-optic dysplasia with amniotic band syndrome sequence: a case report

IntroductionDe Morsier syndrome, or septo-optic dysplasia, is a rare, heterogeneous, complex condition with a highly variable phenotype. It is characterized by optic nerve hypoplasia, pituitary gland hypoplasia, and midline brain abnormalities, including absence of septum pellucidum and corpus callosum dysgenesis. Diagnosis is made clinically by the presence of any two or more features from the clinical triad.Case presentationWe report a case of a premature African newborn male baby born to nonconsanguineous parents who presented to our institution with agenesis of the septum pellucidum, unilateral optic nerve hypoplasia, and pituitary stalk hypoplasia. However, he had intact central endocrine function. He also presented with limb defects due to constricting amniotic band syndrome. Other dysmorphic features were low-set ears, microcephaly, and bilateral talipes equinovarus. He otherwise had a normal neurological examination result. Over time, he had an adequate weight gain and was managed by a multidisciplinary team.ConclusionDe Morsier syndrome still represents a diagnostic challenge, despite advances in neuroimaging and genetic studies, due to the heterogeneous nature of the disorder. This case adds to existing knowledge on the vascular pathogenesis of septo-optic dysplasia.

The Effect of Piracetam on Valproic Acid Induced Congenital Malformations in Swiss Albino Mice

Valproic acid (VPA) is an antiepileptic drug which is widely used in humans and is a well known teratogenic agent when used during pregnancy. Piracetam is a nootropic or cognitive enhancer drug used to treat cognitive impairment in aging, brain injuries as well as dementia. In the present study, these two drugs VPA and Piracetam were administered orally to Swiss albino mice in the doses of400 mg/kg and 800 mg/kg body weight respectively from gestational day (GD) 6-11 in order to see the protective effect of Piracetam against VPA induced teratogenesis. The fetuses were collected on GD 18 after uterotomy and observed for gross malformations if any. In VPA treated group the malformations observed were exencephaly, cranioschisis, limb and tail defects, haemorrhage, resorptions and retardation. No such anomalies were observed in control and Piracetam treated groups. However,in VPA+ Piracetam treated group some resorptions and growth retardation were noted. This group showed highly significant (p < 0.001) protection against the teratogenic effects of VPA treated group though the developmental parameters were significantly reduced (p < 0.001) in comparison to those of group I (control) and group III (receiving piracetam). These findings suggest that Piracetam, if given in higher doses might protect the development in utero against the teratogenic effects of VPA.

Using Freestyle Skin Flap in Closure of Defects in Upper Limb

Background: Defects in upper limb may result from primary open trauma, postoperative wound infection, raw area after burns or post burn scar excision, tumor excision, radiation injury. Some defects require skin flap for proper coverage and restoration of function. One of the methods recently used for reconstruction of defects in upper limb is local freestyle skin flap. This flap is based on a perforator which provides blood supply for flap and acts as pivot point when the flap is rotated. Objectives: To evaluate using freestyle flap for reconstruction of defects in upper limb and assess the post-operative results for restoring function and cosmoses. Patients and Methods: This is a prospective study carried out in Plastic & Reconstructive Surgery Department & Emergency Unit, Zagazig University Hospitals in the period from January to July 2018 including 12 patients with soft tissue loss in upper limb managed by freestyle skin flap. Results: 50% of the cases had soft tissue defect after contracture scar release, while 25% were due to traumatic cause and the remaining 25% were post malignancy resection. flap dimensions ranged from 6 - 96 cm². we had no complications in 58.3% of our cases, while minor complications like flap congestion and distal partial necrosis occurred in 33.4% which were resolved within 1 week. Unfortunately, we experienced 1 flap loss (8.3%) which managed later by debridement of necrotic tissue and skin grafting the remaining soft tissue. Conclusion: Freestyle skin flaps are a reliable option for coverage of small to moderate sized defects

Fetal outcomes after maternal exposure to oral antifungal agents during pregnancy: A systematic review and meta-analysis.

ObjectiveTo assess the risk of adverse fetal outcomes after exposure to oral antifungal agents during pregnancy.Search strategyPubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to October 2018.Selection criteriaCohort studies and case–control studies investigating fetal outcomes following maternal exposure to oral antifungal agents.Data collection and analysisTwo reviewers independently assessed studies for inclusion, assessed risk of bias, and extracted data. Pooled estimates were calculated for the frequency of adverse fetal outcomes.Main resultsOverall, eight cohort studies and one case–control study were included. The oral antifungal agents used during pregnancy were fluconazole and itraconazole. The data indicated that oral fluconazole exposure during pregnancy might slightly increase the risk of congenital heart defects and limb defects relative to the general population; oral itraconazole during pregnancy might increase the risk of eye defects. No difference was found between oral fluconazole/itraconazole exposure and non‐exposure in the risk of other birth defects, spontaneous abortion, or stillbirth.ConclusionOral fluconazole or itraconazole may not increase the risk of birth defects. Nonetheless, the risk of congenital heart defects and limb defects after fluconazole exposure and eye defects after itraconazole exposure should be cautiously investigated.

Optimizing the decellularization process of an upper limb skeletal muscle; implications for muscle tissue engineering

Upper limb muscle reconstruction is required following cancer resection, trauma, and congenital deformities. Current surgical reconstruction of the muscle involves local, regional and free flaps. However, muscle reconstruction is not always possible due to the size of the defect and functional donor site morbidity. These challenges could be addressed with the production of scaffolds composed of an extracellular matrix (ECM) derived from decellularized human skeletal muscle. This study aimed to find an optimal technique to decellularize a flexor digitorum superficialis muscle. The first two protocols were based on a detergent only (DOT) and a detergent-enzymatic protocol (DET). The third protocol avoided the use of detergents and proteolytic enzymes (NDNET). The decellularized scaffolds were characterized using qualitative techniques including histological and immunofluorescent staining and quantitative techniques assessingdeoxyribonucleic acid (DNA), glycosaminoglycan (GAG), and collagen content.The DOT protocol consisting of 2% SDS for 4 hours was successful at decellularizing human FDS, as shown by DNA content assay and nuclei immunofluorescence staining. The DOT protocol maintained the microstructure of the scaffolds as shown by Masson's trichrome staining and collagen and GAG content. DET and NDNET protocols maintained the ECM, but were unsuccessful in removing all DNA content after two cycles of decellularization. Decellularization of skeletal muscle is a viable option for muscle reconstruction using a detergent only technique for upper limb defects. Further testing in vivo will assess the effectiveness of decellularized scaffolds for upper limb muscle skeletal tissue engineering.

Comparative evaluation of the prevalence of congenital malformations de novo in newborns from radiation-contaminated territories of the Bryansk region (1999-2014)

On the basis of official statistics for 1999-2014 there was performed the comparative evaluation of the prevalence of congenital malformations de novo: polydactyly, reduction limb defects and multiple congenital malformations in newborns of radiation-contaminated areas of the Bryansk area residing in areas with the various density of radioactive contamination by long lived radionuclides cesium-137 (from 10.0 to 2523.4 kBq/m) and strontium-90 (from 0.7 to 42.5 kBq/m). The findings showed no statistically significant differences in the prevalence of polydactyly, reduction limb defects and multiple congenital malformations in newborns in the South-Western areas compared to medium regional values, although the maximum value of the amount of congenital malformations de novo is found in most radiation-contaminated areas.