RESUMEN
The objective is to establish whether a pattern of intestinal dysbiosis exists in calcium oxalate (CaOx) lithiasis and, if so, to identify its characteristics and explore whether there are differences in the pattern between CaOx dihydrate (COD) and monohydrate (COM) lithiasis. With this aim 24 patients diagnosed with CaOx lithiasis by means of optical microscopy and spectrometry were prospectively recruited. Faecal analysis was carried out by means of RT-PCR 16S rRNA assay and agar plate culture according to the methodology proposed by the Institute of Microecology (Herborn, Germany). The total number of bacteria was depleted due to COD lithiasis (p = 0.036). The mean values of immunoregulating microbiota were normal, but the percentage of normal values was lower in the COD group (30%) than in the COM group (69.2%) (p = 0.062). The total mean values of protective microbiota were normal in both groups. There was a large decrease in the mean values of the muconutritive microbiota Akkermansia muciniphila and Faecalibacterium prausnitzii, the most intense decline being observed in the COD group (p = 0.019). Levels of proteolytic microbiota were elevated in both groups, without differences between them. We conclude that patients with CaOx lithiasis have a chronic pro-inflammatory intestinal dysbiosis pattern characterised by a reduction in the total number of bacteria, a reduction in immunoregulating microbiota and a large reduction in muconutritive microbiota that is significantly more intense in COD lithiasis than in COM lithiasis.
Asunto(s)
Oxalato de Calcio/análisis , Disbiosis/complicaciones , Intestinos/microbiología , Litiasis/química , Litiasis/complicaciones , Femenino , Humanos , Inflamación/complicaciones , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
INTRODUCCIÓN: las urolitiasis implican morbilidad y costos económicos sustanciales. Para su manejo resulta fundamental una evaluación clínica y de laboratorio, que incluya el estudio de la composición química. OBJETIVO: determinar la frecuencia de presentación de los diferentes tipos de urolitiasis según su composición y su relación con el sexo de los sujetos. MÉTODOS: estudio descriptivo, transversal. Se incluyeron las urolitiasis de adultos cubanos, enviadas al Laboratorio de Fisiopatología Renal del Instituto de Nefrología para estudio de composición química, en el período 2001-2011. Las litiasis fueron analizadas con un espectroscopio infrarrojo modelo Philips PU9516. Los diferentes compuestos se identificaron mediante comparación con espectros de referencia. Toda la información fue procesada automatizada (SPSS 15.0.). Se utilizó análisis de distribución de frecuencias. Para probar la existencia de diferencias entre los sexos, en cuanto al tipo de litiasis, se emplearon los tests: de independencia y exacto de Fisher. RESULTADOS: de las 1851 litiasis analizadas, 1316 (71,1 %) eran litiasis simples. Las litiasis simples de oxalato de calcio constituyeron el 46,8 % del total. Dentro de las compuestas, las más frecuentes fueron las de oxalato de calcio más fosfato de calcio (24,7 %). La frecuencia de las litiasis de oxalato de calcio y ácido úrico resultó mayor entre los hombres (p= 0,00), y las de fosfato de calcio y de estruvita (p= 0,00), entre las mujeres. CONCLUSIONES: los cálculos cálcicos, fundamentalmente de oxalato de calcio monohidratado, son los más comunes en la población litiásica estudiada. Las litiasis de oxalato de calcio y ácido úrico son más comunes entre los hombres, mientras las de estruvita y fosfato de calcio lo son, entre las mujeres.
INTRODUCTION: urolithiasis imply significant morbidity and economic costs. For its management, it is fundamental to make clinical and lab evaluation including the study of the chemical composition. OBJECTIVE: to determine the frequency of occurrence of several types of urolithiasis according to their composition and relationship with the individual's sex. METHODS: descriptive and cross-sectional study that included urolithiasis of Cuban adults sent to the Renal Physiopathology Lab of the Institute of Nephrology for the study of chemical composition in the 2001-2011 period. A Philips PU9516 infrared spectroscope served to analyze lithiasis. The various compounds were identified by comparing them with the reference spectra. All the data were collected and processed with SPSS 15.0; the frequency distribution analysis. Independence test and Fisher's exact test were used to confirm the differences between sexes in terms of type of lithiasis. RESULTS: of 1815 analyzed lithiasis, 1316 (71.1 %) were simple. Simple calcium oxalate lithiasis represented 46.8 % of the total number. In the combinations, the most frequent were calcium oxalate plus calcium phosphate (24.7 %). The frequency of calcium oxalate and uric acid lithiasis was higher in men (p= 0.00 and those of calcium phosphate and struvite (p= 0.00) in women. CONCLUSIONS: calcium stones, mainly monohydrated calcium oxalate, are the most common in the studied lithiatic population. Calcium oxalate and uric acid are the commonest in men whereas struvite and calcium phosphate are more frequent in women.
Asunto(s)
Humanos , Masculino , Femenino , Análisis Espectral/métodos , Cálculos Urinarios/química , Litiasis/química , Urolitiasis/epidemiología , Epidemiología Descriptiva , Estudios Transversales/métodosRESUMEN
BACKGROUND: Because dacryoliths occur at low frequency, few studies have focused on their composition. We aimed to present findings from morphological, chemical, and mineralogic analysis of 86 dacryoliths. METHODS: We studied 86 dacryoliths obtained during 832 dacryocystorhinostomies (DCR) performed for postsaccal obstruction. We examined the samples with atomic infrared spectrometry (80 samples), amino acid analysis (17 samples), scanning electron microscopy, and an electron microprobe with an energy dispersive detector (seven samples). RESULTS: Dacryoliths were found in 86/832 DCRs (10.3 %), mostly in patients with primary acquired nasolacrimal duct obstruction. All the dacryoliths were soft, composed of organic material, including proteins and mucoproteins, with approximately 20 % amino acid content. There were no "hard" dacryoliths composed of calcium phosphate. The stones were composed of lobes and lobules built on an amorphous core material with small cavities, probably as a result of various chemical processes that produced a gaseous product. The most frequent elements found in inorganic inclusions were silicon, magnesium, sulfur, potassium, calcium, sodium, and chlorine. Also, some particles had high contents of bismuth, titanium, iron, and organic fibers. The fibers found in the core of dacryoliths suggested a potential origin from cotton swabs used in cosmetics. CONCLUSION: Dacryoliths are composed almost exclusively of organic material, including proteins and mucoproteins, with approximately 20 % amino acid content.
Asunto(s)
Cálculos/química , Enfermedades del Aparato Lagrimal/diagnóstico , Litiasis/química , Litiasis/diagnóstico , Conducto Nasolagrimal/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Aminoácidos/análisis , Calcio/análisis , Cálculos/ultraestructura , Niño , Preescolar , Dacriocistorrinostomía , Microanálisis por Sonda Electrónica , Femenino , Humanos , Lactante , Enfermedades del Aparato Lagrimal/cirugía , Litiasis/cirugía , Masculino , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Mucoproteínas/análisis , Espectroscopía Infrarroja por Transformada de Fourier , Adulto JovenRESUMEN
AIMS: Excessively acidic urine is the dominant factor in uric acid stone formation. Recent evidence implicating insulin resistance has revived interest in its causation. We reviewed data on uric acid stone formers attending a general stones clinic to find out whether this supports and adds to current concepts. METHODS: A retrospective database study of 1504 stone formers investigated at the Southampton renal stones clinic from 1990 to March 2007. Uric acid stone formers and idiopathic calcium stone formers were compared using non-parametric tests. RESULTS: Fifty-nine patients (3.9%; 43 men) had uric acid stones. In men the commonest associated conditions were diabetes (20%), gout (20%) and an ileostomy (15%); in women, diabetes (33%), urinary infections (27%) and hyperparathyroidism (20%). Most patients with diabetes (85% of men, 75% of women), however, produced calcium stones. Risk factors did not differ significantly between calcium and uric acid stone formers with diabetes, gout or ileostomies. The median urine pH of men with idiopathic calcium stones was 6.20, idiopathic uric acid stones 5.47, diabetes 5.68, gout 6.05, diabetes and gout 5.20 and ileostomy 5.10. Plasma urate was higher with gout and idiopathic uric acid stones. Urate excretion was increased in gout. Oxalate excretion was lower with idiopathic uric acid stones (new finding). Urine volume decreased and oxalate concentration increased with ileostomy. CONCLUSIONS: Uric acid stones are increased in diabetes, but most patients with diabetes make calcium stones. Different mechanisms may explain low pH with diabetes, gout and idiopathic stones. Low oxalate excretion with idiopathic urate stones needs confirmation.
Asunto(s)
Cálculos/química , Cálculos/epidemiología , Cálculos/etiología , Ácido Úrico/análisis , Calcio/análisis , Femenino , Humanos , Litiasis/química , Litiasis/epidemiología , Litiasis/etiología , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
A 4-year-old, female, spayed, Labrador retriever was presented with a painless swelling of the left ventromedial eyelid and epiphora of 3 months duration. Bilateral patency of the nasolacrimal system was confirmed by the appearance of fluorescein dye at both nares. Ultrasonography revealed a well-demarcated fluid-filled structure containing echogenic ill-defined material in close proximity to the nasolacrimal system. A transconjunctival surgical approach confirmed the close anatomical proximity of the cyst and the absence of a communication with the inferior canaliculus. The cyst contained multiple intraluminal calculi (dacryoliths). Following surgical excision of the cyst, the epiphora resolved and no recurrence was noted over a 12-month follow-up period. On histopathology, the cystic structure was lined by stratified squamous epithelium, consistent with lacrimal canaliculus epithelium. Presumed progression of a canalicular diverticulum to a cyst with the formation of intraluminal dacryoliths was suspected. Mineral analysis of the dacryoliths revealed a calcium carbonate composition.
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Enfermedades de los Perros/diagnóstico , Enfermedades del Aparato Lagrimal/veterinaria , Litiasis/veterinaria , Minerales/química , Animales , Enfermedades de los Perros/patología , Perros , Femenino , Enfermedades del Aparato Lagrimal/diagnóstico , Enfermedades del Aparato Lagrimal/patología , Litiasis/química , Litiasis/diagnóstico , Litiasis/patologíaRESUMEN
The authors review the mineralogical methods and techniques of analyzing calculi, stony concretions in the body. They discuss the main types of kidney stones (prostate, testicular, salivary, and bile) and the different diagnostic methods in mineralogy. By applying the techniques of optical microscopy and electron microscopy, they describe the different characteristics of human stones, based on extensive experience as evidenced by their numerous studies.
Asunto(s)
Cálculos/diagnóstico , Técnicas Citológicas , Geología/métodos , Litiasis/diagnóstico , Cálculos/química , Cálculos/ultraestructura , Cálculos/orina , Cristalización , Cristalografía por Rayos X , Cisteína/química , Femenino , Enfermedades de los Genitales Masculinos/diagnóstico , Humanos , Cálculos Renales/diagnóstico , Litiasis/química , Litiasis/ultraestructura , Litiasis/orina , Masculino , Microscopía Electrónica , Ácido Oxálico/química , Fosfatos/química , Valor Predictivo de las Pruebas , Enfermedades de la Próstata/diagnóstico , Ácido Úrico/químicaAsunto(s)
Enfermedades del Íleon/diagnóstico , Litiasis/diagnóstico , Fosfatos de Calcio/análisis , Femenino , Humanos , Enfermedades del Íleon/diagnóstico por imagen , Enfermedades del Íleon/patología , Enfermedades del Íleon/cirugía , Litiasis/química , Litiasis/diagnóstico por imagen , Litiasis/patología , Litiasis/cirugía , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
BACKGROUND: Rhinolithiasis is masses that result from the deposition of salts around an intranasal foreign body. Rhinoliths are rare and rhinolithiasis is generally reported in the literature in single case studies. This study presents 21 cases of rhinolithiasis with a large series of clinical findings, diagnosis, and treatment. METHODS: A total of 21 patients diagnosed with rhinolithiasis were identified. Clinical presentations, signs, and symptoms of the patients with radiological findings are presented, and x-ray diffraction analyses of three of the removed rhinoliths were performed to assess their mineralogical composition. RESULTS: A total of 21 patients (9 male and 12 female patients; age range, 4-63 years) diagnosed with rhinolithiasis were reviewed in this study. The most common symptoms were noted as purulent rhinorrhea and nasal obstruction. The other symptoms were headache, oral malodor, and recurrent epistaxis. Nasal endoscopic examination was used for diagnosis of all patients. Endoscopic nasal examinations and computerized tomography (CT) findings revealed that rhinolithiasis was accompanied by sinusitis, chronic vestibulitis, allergic rhinitis, septum deviation, and squamous cell carcinoma. Rhinoliths were fully excised by using endoscopic nasal surgery. Mineralogical analyses of the three removed stones revealed dahllite [Ca(5)(PO(4),CO(3))(3)OH]. CONCLUSION: Cases of rhinolithiasis are seen rarely. It should always be considered in patients complaining from long-term unilateral nasal obstruction and unilateral purulent rhinorrhea. The treatment involves the removal of the rhinolith and the use of appropriate antibiotic therapy to control local infection. Rigid nasal endoscopy is the most important method to be used in diagnosis and treatment.
Asunto(s)
Litiasis/diagnóstico , Enfermedades Nasales/diagnóstico , Adolescente , Adulto , Niño , Preescolar , Endoscopía , Femenino , Humanos , Litiasis/química , Litiasis/cirugía , Masculino , Persona de Mediana Edad , Enfermedades Nasales/cirugía , Tomografía Computarizada por Rayos XRESUMEN
Se presenta por primera vez un estudio sobre la frecuencia de litiasis urinaria en la ciudad de San Luis, Argentina, a partir de datos de espectroscopía infrarroja. Se analizaron los espectros infrarrojos de 169 cálculos urinarios provenientes de centros sanitarios tanto públicos como privados. Los componentes químicos encontrados fueron oxalato de calcio monohidrato, uratos, fosfato de calcio, fosfato amónico magnésico hexahidrato y de composición mixta. El análisis cuantitativo de los datos, utilizando la estadística descriptiva, permitió determinar el tipo de composición litiásica más frecuente en el total de los sujetos y la distribución de los tipos encontrados según sexo y edad. La frecuencia de oxalato de calcio monohidrato y de uratos fue mayor en hombres que en mujeres correspondiendo a una franja etaria entre 21 y 60 años y entre 41 y 70 años, respectivamente. Esta relación se invierte en los fosfatos de calcio o magnesio presentando mayor incidencia en mujeres. Los cálculos de composición mixta se distribuyen de igual manera entre hombres y mujeres.
A study dealing with urinary lithiasis frequency in San Luis city, Argentina, applying infrared spectroscopy is reported for the first time. The infrared spectra of 169 urinary stones provided by public and private sanitary centers were analyzed. The most frequent chemical components found were calcium oxalate monohydrate, urates, calcium phosphate, magnesium ammonium phosphate hexahydrate and mixed compositions. Quantitative data analysis, performed by descriptive statistics enabled the determination of the most frecuent lithiasic composition for all the cases, as well as its distribution according to the corresponding age and sex. Calcium oxalate monohydrate and urates were more frequently found in men than in women ranging between 21- 60 and between 41-70 years old, respectively. The inverse ratio is determined for calcium or magnesium phosphates, women being the most affected. Stones with mixed composition showed the same incidence in women and men.
Asunto(s)
Humanos , Espectroscopía Infrarroja Corta/estadística & datos numéricos , Urolitiasis/orina , Argentina , Enfermedades Urológicas/orina , Litiasis/químicaRESUMEN
BACKGROUND: Microlithiasis has been identified as a cause of idiopathic acute pancreatitis in patients with an intact gallbladder. Microlithiasis has also been identified in the bile of some patients who have undergone cholecystectomy. However, it is unknown whether bile microlithiasis causes postcholecystectomy pain. OBJECTIVE: To identify bile microlithiasis in patients with postcholecystectomy pain and to investigate the therapeutic effect of ursodeoxycholic acid (urso) on such patients with microlithiasis in the bile. DESIGN: Prospective randomized trial. SETTING: Tertiary medical center. PATIENTS: Patients with postcholecystectomy pain and bile crystals. INTERVENTIONS: Urso treatment. MAIN OUTCOME MEASUREMENTS: The severity and frequency of right upper-quadrant abdominal pain were compared with and without urso treatment, and before and after urso treatment. RESULTS: A total of 118 patients with postcholecystectomy pain were screened for the study. Twelve patients (10%) were identified with bile crystals. In the first phase, 6 of these patients received urso treatment, whereas the other 6 patients did not receive urso treatment. In the second phase, the latter 6 patients were given the urso treatment. After using urso for a few months, their biliary-type abdominal pain significantly improved or resolved. In the control group, there was no improvement in symptoms. There was a significant difference between the 2 groups (P = .01). LIMITATIONS: Single-center, small number of patients. CONCLUSIONS: This study provided evidence that supports the hypothesis that bile microlithiasis is indeed a cause for postcholecystectomy pain. Patients with such postcholecystectomy pain may benefit from a microscopic examination of bile for crystals or microlithiasis, and urso treatment if bile crystals are identified.
Asunto(s)
Colecistectomía Laparoscópica/efectos adversos , Coledocolitiasis/tratamiento farmacológico , Dolor Postoperatorio/tratamiento farmacológico , Ácido Ursodesoxicólico/uso terapéutico , Adulto , Colangiopancreatografia Retrógrada Endoscópica/métodos , Colecistectomía Laparoscópica/métodos , Coledocolitiasis/diagnóstico , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Litiasis/química , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Dolor Postoperatorio/diagnóstico , Probabilidad , Estudios Prospectivos , Valores de Referencia , Medición de Riesgo , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas , Resultado del TratamientoAsunto(s)
Colagogos y Coleréticos/uso terapéutico , Colecistectomía Laparoscópica/efectos adversos , Coledocolitiasis/diagnóstico , Dolor Postoperatorio/diagnóstico , Colangiopancreatografia Retrógrada Endoscópica/métodos , Colecistectomía Laparoscópica/métodos , Coledocolitiasis/tratamiento farmacológico , Femenino , Estudios de Seguimiento , Humanos , Litiasis/química , Masculino , Dolor Postoperatorio/tratamiento farmacológico , Selección de Paciente , Cuidados Posoperatorios/métodos , Medición de RiesgoRESUMEN
An abnormal chest shadow was pointed out in a 56-year-old woman in a health check in 2001. She had pulmonary tuberculosis at age 11. Because of repeated fever for the previous 2 years, she visited our hospital in 2003 and right upper lobe pneumonia was detected with a calcified nodule that completely obstructed the right upper lobe bronchus on CT. After admission, she spontaneously expectorated a stone. The composition of the stone was 57% calcium phosphate and 43% calcium carbonate. Radiological findings and the composition of the stone suggested that this broncholith was calcified bronchial mucus rather than a calcified lymph node that might have perforated into the airway. Bronchiectasis of the right B3 broncus was observed on CT scan after lithoptysis. Although the bronchiectasis was unchanged 2 years later, she had no symptoms, such as fever or cough.
Asunto(s)
Enfermedades Bronquiales/complicaciones , Bronquiectasia/etiología , Litiasis/complicaciones , Neumonía/etiología , Carbonato de Calcio , Fosfatos de Calcio , Femenino , Humanos , Litiasis/química , Persona de Mediana Edad , Pronóstico , Recurrencia , Remisión Espontánea , Tuberculosis Pulmonar/complicacionesRESUMEN
BACKGROUND: Rhinolithiasis is a rare and under-diagnosed clinical entity whose etiology and pathogenesis is poorly understood. OBJECTIVE: The objective of the study is to review the clinical and radiologic features of rhinolithiasis and mineralogical-chemical composition of the rhinoliths with the aim of shedding light on its etiology and pathogenesis. METHODS: Our subjects consisted of 8 rhinolithiasis cases. Clinical presentations, signs, and symptoms of the patients with radiologic findings are presented, and X-ray diffraction analyses of the stones were carried out to assess their mineralogical composition. RESULTS: Nasal obstruction appeared to be the chief symptom, followed by nasal discharge and facial pain. Neither exogenous nor endogenous nidi were identified in any of the cases. Mineralogical analyses of the rhinoliths revealed Whitlockite [(Ca,Mg)3 (PO4)2] in one and Dahllite [Ca5 (PO4,CO3)3OH] in 7 cases. CONCLUSION: We hypothesized that some substances or organic objects form the nidi of the rhinoliths and are disintegrated over the course of mineral precipitation. This hypothesis was supported by radiologic and microscopic findings.
Asunto(s)
Litiasis/complicaciones , Minerales/análisis , Obstrucción Nasal/etiología , Senos Paranasales/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Humanos , Litiasis/química , Litiasis/diagnóstico por imagen , Masculino , Obstrucción Nasal/diagnóstico por imagen , Obstrucción Nasal/metabolismo , Pronóstico , Índice de Severidad de la EnfermedadRESUMEN
Measuring crystallization processes for assessing the risk of stone formation or the effect of treatment on that risk. In summary, crystallization processes are involved in the risk for stone formation at several levels. Several tests are available for assessing if crystalization is disturbed. It is important to first establish for which part of the urinary tract the information is sought and then adapt the experimental conditions to that site [53]. This information helps in visualizing what is happening inside the urinary tract of a SF and what the treatment measures prescribed may do to change that situation.
Asunto(s)
Cálculos Renales/química , Litiasis/química , Cristalización , Humanos , Litiasis/metabolismoRESUMEN
OBJECTIVE: To present two cases of intrascrotal lithiasis associated with hydrocele and the results of the crystallographic study. METHODS: Three intrascrotal calculi in two patients aged 72 and 75 years that underwent surgery for hydrocele were analyzed. Two 2-mm. calculi were incidentally discovered during surgery for a right hydrocele in one patient. An ultrasound scan of the other patient showed a left hydrocele with a free-floating, round, hyperechoic, 6-mm. calculus, with posterior acoustic shadow. None of the patients had a previous history of trauma. The 3 calculi were white and smooth, but turned yellow and rough after removal. Scanning electron microscopy and x-ray dispersion studies were performed. RESULTS: All 3 calculi had a center comprised of hydroxyapatite and white organic matter, and an exterior of yellow organic matter. The mineral portion of the center of the 6-mm. calculus and one of the 2-mm. calculi was composed of 33% phosphorus and 67% calcium, and the other 2-mm. calculus contained 32% phosphorus and 68% calcium by x-ray dispersion analysis. CONCLUSIONS: Intrascrotal lithiasis is rare. In the two cases described herein, we observed abundant organic matter, particularly on the stone surface, and hydroxyapatite, particularly in the center. Among the possible etiologic causes, the deposit of organic matter in the presence of high oversaturation of calcium phosphates and absence of crystallization inhibitors, can initiate calcification and the subsequent collection of organic matter makes the process irreversible.
Asunto(s)
Durapatita/análisis , Litiasis/química , Escroto , Hidrocele Testicular/complicaciones , Anciano , Cristalografía por Rayos X , Humanos , Litiasis/diagnóstico por imagen , Litiasis/etiología , Litiasis/cirugía , Masculino , Microscopía Electrónica de Rastreo , Compuestos Orgánicos/análisis , Escroto/diagnóstico por imagen , Escroto/cirugía , Hidrocele Testicular/diagnóstico por imagen , Hidrocele Testicular/cirugía , UltrasonografíaRESUMEN
Pancreatic stones from 25 patients were compared by morphological and/or radiological examination. Twenty patients, mostly alcoholics, had calcified stones. Five (four nonalcoholic women) had radiolucent stones. Aspect and consistency of calcified stones varied from compact and resistant to coralliform and brittle but were identical in the same patient. In the coralliform type, organic fibrils with a diameter up to 10 microm and a length up to a few centimeters were observed, strongly attached to mineral crystals. The lithostathine (formerly called pancreatic stone protein, PSP) content was estimated in each stone significantly lower in the populations with larger stone mass, compared to populations with small amounts of stones. Transparent stones were built up of an amorphous material solubilized at acidic pH and corresponding to degraded forms of lithostathine-S (S for secretory). In one patient, we followed over seven years the evolution of a radiolucent calculus. We observed that the radiolucent core occurred first, and was secondarily wrapped in a calcified shell. We conclude that morphological differences observed in this study among pancreatic stones suggest that different mechanisms have been involved in their formation. Among them, lithostathine transformation into insoluble polypeptides may provide different types of protein aggregates, some of them being able to promote CaCO(3) apposition and others having no affinity for calcium.