Steering the conversion of protein residues to volatile fatty acids by adjusting pH.

This study investigates the influence of pH on protein conversion into volatile fatty acids by anaerobic mixed-culture fermentation, a topic that, in contrast to glucose fermentation, only had scarce and contradictory information available. Several experiments were performed with two model proteins (casein and gelatin) at three different pH values (5, 7 and 9) using chemostats and batch tests. Highest conversion was reached at neutral pH although complete acidification was never achieved. Longer chain carboxylates production was favoured at low pH, while acetic acid was the main product at pH 7 and 9. Amino acids preferential consumption also varied with pH and protein composition. In fact, protein conversion stoichiometry is mainly driven by energetic yields and amino acid molecular configuration. Overall, this study identifies pH adjustment as a way to steer volatile fatty acid production during mixed-culture fermentation of proteins.

Utilidad de la resonancia magnética en el diagnóstico de las enfermedades musculares hereditarias / Utility of magnetic resonance imaging in the diagnosis of hereditary muscular diseases

Hereditary muscular diseases are rare disorders, due to a genetic defect that causes an alteration in the structure or function of the muscle fibers. They may present at any stage of life and their definitive diagnosis usually requires muscle biopsy. While the most frequent hereditary myopathies have a relatively characteristic clinical presentation, there is a substantial part thereof in which the symptoms are non-specific and the definitive diagnosis may take a long time. Magnetic Resonance Imaging (MRI) has earned a place in the diagnostic process of this last group of myopathies, confirming the presence of muscle involvement and raising diagnostic approaches based on its distribution, information that guides the immunohistochemical and/or genetic study necessary for the definitive diagnosis. In this article we review the basic study protocols with MRI of the myopathies and their interpretation, also showing some cases of these diseases.

Las enfermedades musculares hereditarias son patologías raras, debidas a un defecto genético que causa una alteración en la estructura o funcionamiento de las fibras musculares. Pueden debutar en cualquier etapa de la vida y su diagnóstico definitivo suele requerir de biopsia muscular. Si bien las miopatías hereditarias más frecuentes tienen una presentación clínica relativamente característica, existe una parte importante de ellas en que los síntomas son poco específicos y su diagnóstico definitivo puede tomar largo tiempo. La Resonancia Magnética (RM) ha ganado un espacio en el proceso diagnóstico de este último grupo de miopatías, confirmando la presencia del compromiso muscular y planteando aproximaciones diagnósticas en base a su distribución, información que acota el estudio inmunohistoquímico y/o genético necesario para el diagnóstico definitivo.En el presente artículo revisaremos los protocolos de estudio básico con RM de las miopatías y su interpretación, mostrando también algunos casos de estas enfermedades.

Las disartrias / The dysarthrias

The dysarthrias are a group of motor alterations of the speech as consequence of a neurological impairment that represent the 54% of the total of disorders that impair oral communication. Several types of dysarthrias could be determined according to the location of the causing lesion, the neurological mechanisms implicated in its generation, and functional characteristics of the speech. Clinical evaluation of the dysarthrias should include the clinical history, physical examination and the motor assessment of the speech. Prognosis is determined by the etiology and severity of the disorder. The objective of the treatment is to satisfy daily communicational needs of the patient in consideration to the underlying neurological condition (AU)

Comprensión de la pantomima en pacientes afásicos / Pantomime comprensing in aphasics patients

Los afásicos presentan alteraciones en la comprensión de la pantomima, sin embargo, existe controversia sobre si su causa es de tipo simbólica o práxica. Este estudio compara el rendimiento en la Pauta Exploratoria de Comprensión de la Pantomima (PECP) en un grupo de afásicos y un grupo control, se analiza el tipo de error cometido y las variables que influyen en sus rendimientos. Los resultados indican que los afásicos rinden significativamente menos que los normales, el error más frecuente en ambos grupos es el de relación semántica. Las variables que influyen en el rendimiento son: deterioro intelectual, severidad de la afasia y presencia de anosognosia. El estudio muestra evidencia que apoya al déficit del componente simbólico para explicar el déficit en la comprensión de la pantomima en los afásicos.

Disposition of 4,6,4'-trimethylangelicin in mice maintained in the dark and after UVA irradiation.

The disposition of the furocoumarin 4,6,4'-trimethylangelicin (4,6,4'-TMA) was studied in mice. After oral administration of (3)H 4,6,4'-TMA, radioactivity measured in serum shows fast absorption and slow elimination. Serum protein binding is higher as compared to 8-methoxypsoralen (8-MOP), currently used in photochemotherapy (PUVA) and linearly declines from 30 min to 6 h after administration. Distribution in the various organs was similar to that of 8-MOP and was relatively uninfluenced by UVA radiation, required for the biological effects of 4,6,4'-TMA. Mice eliminate (3)H 4,6,4'-TMA mostly through the urine, but also through the faeces. Two metabolites were identified in the urine and serum of the treated mice, one of which proved to be a derivative of 4,6,4'-TMA, formed by hydrogenation of the double 4',5' bond of the furocoumarin nucleus.

Abnormal expression of MDM2 in prostate carcinoma.

Mutation of p53 is rare in localized prostate carcinoma. The oncoprotein MDM2, whose gene has a response element for p53, promotes the degradation of p53 protein and inhibits its transcriptional activation of genes related to cell cycle arrest and apoptosis, constituting a negative feedback control. We studied p53 and MDM2 expression by immunohistochemistry and looked for mutations in p53 exons 5 to 8 by polymerase chain reaction-single strand conformational polymorphism in 118 patients submitted to radical prostatectomy for localized prostate cancer. In 28 cases, we studied cell proliferation by immunohistochemistry, using antibody for Ki-67, and apoptosis by the deoxynucleotidyl transferase mediated dUTP biotin nick end labeling technique. Although no p53 mutations were found, p53 protein was detected in 31.4% of the cases, and these cases had higher Gleason scores (P = .03) and more advanced tumor stages (P = .02). MDM2 was overexpressed in 40.7% of the cases, and these cases had greater tumor volumes (P = .001). Tumors that were positive for both p53 and MDM2 were larger (P = .003) and of more advanced stage (P = .03). Within the 28-case subset, the proliferative index was higher among MDM2-positive tumors (P = .046), and the apoptotic index was lower among p53-positive tumors (P = .01). We conclude that, although p53 mutation is a rare event in prostate carcinogenesis, the detection of p53 protein by immunohistochemistry is common and is associated with decreased apoptosis and increased histologic grade and tumor stage. We also conclude that the overexpression of MDM2 has a role in prostate carcinogenesis, being frequently detected and associated with increased cell proliferation and tumor volume. Finally, we propose that the MDM2-positive/p53-positive phenotype identifies prostate cancers with aggressive behavior.

Presence of apolipoprotein E epsilon4 allele in cerebral palsy.

The apolipoprotein E gene, which is located on chromosome 19, has three alleles (epsilon2, epsilon3, and epsilon4). Several recent publications associate the presence of the apolipoprotein E epsilon4 allele with the occurrence of neurologic diseases, and consider it a risk factor for the development of central nervous system affections. A group of 40 patients with cerebral palsy was studied and compared to a control group of 40 subjects, and higher occurrence of the allele epsilon4 in the group of subjects with cerebral palsy was observed. A significantly higher risk of developing cerebral palsy was demonstrated among those subjects with the apolipoprotein E epsilon4 allele.

Methylation of the hMLH1 promoter but no hMLH1 mutations in sporadic gastric carcinomas with high-level microsatellite instability.

Microsatellite instability (MSI) in tumors from patients with hereditary non-polyposis colorectal cancer (HNPCC) is caused by germline mutations in mismatch repair (MMR) genes, principally hMSH2 and hMLH1. In contrast, somatic mutations in MMR genes are relatively rare in sporadic MSI(+) colon cancers. Rather, the majority of mutation-negative, MSI(+) cases involve hypermethylation of the hMLH1 promoter and subsequent lack of expression of hMLH1. The details of the mechanisms of this epigenetic gene silencing remain to be elucidated. In some colon cancer cell lines, hMLH1 promoter methylation is accompanied by mutation of 1 of the 2 alleles, whereas in other cell lines and tumors, such combinations have not been reported. To contribute to the characterization of MSI in gastric cancer and to directly investigate whether hMLH1 promoter methylation is accompanied by gene mutation in these cancers, we have analyzed 42 gastric tumors and corresponding normal tissue for MSI, hypermethylation of the hMLH1 promoter, and mutations in hMLH1 as well as hMSH2. We found that 10 (23.8%) of 42 cases of sporadic gastric cancer were MSI(+) and that 8 had at least 2 of 12 altered microsatellite loci. All samples with at least 2 altered loci exhibited methylation of the hMLH1 promoter region, but none had detectable mutations in hMLH1 or hMSH2. Our results confirm the importance of methylation of the hMLH1 promoter region in MSI(+) gastric tumors and suggest that methylation takes place in the absence of hMLH1 mutations in these tumors.

Microsatellite instability in tumors as a model to study the process of microsatellite mutations.

We screened 42 sporadic gastric tumors and found that seven of them had significant microsatellite instability. These were then studied at 26 microsatellite loci, comprising di-, tri- and tetranucleotide repeats. The instability level of individual microsatellites in the tumors was found to be positively correlated with the population average heterozygosity and variance of repeat number of the microsatellite loci, as predicted by the stepwise mutation model. Moreover, as is known to occur in human populations, instability was strongly correlated with the number of repeats at each microsatellite locus and with the perfection of the reiterated sequence. These results demonstrate that microsatellite mutations in unstable tumors show similarities to germline mutations and suggest that their study may be useful in understanding the mechanisms that generate microsatellite variability in human populations. We used this model to test the claims that the microsatellite mutation process is biased towards increased size and heterozygosity with wide differences in allele sizes. These assertions were not confirmed.

Prevention of neoplastic port site implants in laparoscopy: an experimental study.

Enthusiasm about the application of videolaparoscopy to oncologic diseases has been limited by the growing number of port site implants. Adult Wistar rats were submitted to 6-7 mm Hg carbonic gas pneumoperitoneum. Rats were randomly divided into two groups: group I rats with tumor (200,000 viable cells of Walker tumor) and group 11 rats with no tumor. The pneumoperitoneum was deflated after 30 min. Group I was further randomized into five groups: no treatment; or abdominal irrigation with saline, heparin, chemotherapy (doxorubicin), or chemotherapy associated with heparin. After a period lasting no more than 18 days, the abdominal wall and intraperitoneal organs macroscopically affected were studied histologically. Chemotherapy groups had no port site implants and were significantly different (p < 0.05) than the no treatment, saline, and heparin solution groups, which had incisional implants at frequencies of 100%, 85.7%, and 82.5%, respectively. Intraperitoneal irrigation with chemotherapy solution was effective in preventing incisional implants in this animal model.

Long-term follow-up of cranial bone graft in dorsal nasal augmentation.

A follow-up of 363 cranial bone grafts for nasal reconstruction is presented. The main indications for the surgery were congenital, posttraumatic, or postrhinoplasty deformity. The results were satisfactory in the vast majority of cases. The complications associated with the grafts and with the donor site are discussed, as are the methods to treat and prevent these complications from occurring.

Genetic damage in exfoliated cells of the uterine cervix. Association and interaction between cigarette smoking and progression to malignant transformation?

OBJECTIVE: To determine, through the micronucleus (MN) test, the cytogenetic effects of cigarette smoking on exfoliated cells from the uterine cervix in women with normal smears and women with inflammatory atypia, squamous intraepithelial lesion (SIL) (cervical intraepithelial neoplasia [CIN] 1-3) and cervical cancer. STUDY DESIGN: The study group consisted of 200 women divided into three subgroups: group 1 (n = 116), women periodically undergoing cervical cytology and residents of Salvador-Bahia; group II (n = 57), women residing in São Paulo and previously selected because of a possible cytopathologic test positive for such conditions as human papillomavirus infections or malignant or premalignant cervical lesions (CIN 1-3); group III (n = 27), inmates of the Tatuapé Penal Institution, São Paulo. All the women underwent cytologic and colposcopic examination, and biopsies were performed on 68 of them. RESULTS: Considering the samples as a whole and using the chi(2) test for rare events, the number of MNs in smokers was significantly greater than in nonsmokers. It was also greater in women with larger exposure to smoking. The occurrence of MN was significantly lower in women with normal smears (smokers and nonsmokers) than in those showing any kind of pathologic alteration. In nonsmokers the occurrence of MN was similar between those with inflammatory atypia (IA) or low grade (L) SIL (CIN 1) and significantly higher in women with more severe lesions or high grade (H) SIL (CIN 2 and 3). Smokers with LSIL (CIN 1) showed a higher number of MNs than nonsmokers with a comparable diagnosis and smokers with IA. No differences were observed when compared with smokers with HSIL (CIN 2 and 3). MN occurrence was not associated with other risk factors for SIL or cancer development, such as age at first coitus, number of sexual partners, multiparity and use of hormonal contraceptives. CONCLUSION: These results suggest that the mutagenic effect of cigarette smoking occurs in cervical cells and that the progression of SIL is associated with increased frequency of chromosomal damage. Moreover, the data suggest that cigarette smoking introduces an additional risk to the progression of low grade LSIL (CIN 1). MN testing would be helpful in monitoring smokers with this kind of lesion.

PIP: Previous studies have shown that cigarette smoking increases the risk of developing squamous intraepithelial lesion (SIL) and cervical cancer. The present study used the micronucleus test to assess the cytogenic effects of smoking on exfoliated cells from 3 subgroups of Brazilian women: group 1 (n = 116), women periodically undergoing cervical cytology; group 2 (n = 57), women with a possibly positive cytologic test for human papillomavirus or malignant or premalignant cervical intraepithelial neoplasia (CIN 1-3); and group 3 (n = 27), inmates of the Tatuape Penal Institute. Overall, micronucleus frequency was significantly greater in smokers than in nonsmokers. The occurrence of micronuclei was significantly lower in women with normal smears (regardless of smoking status) than in women with any evidence of pathologic alterations. In nonsmokers, micronucleus frequency was similar in women with inflammatory atypia or low-grade CIN and significantly higher in women with more severe lesions and CIN 2-3. Smokers with CIN 1 had more micronuclei than nonsmokers with a comparable diagnosis and smokers with inflammatory atypia. No differences were observed in comparisons with smokers with CIN 2-3. Micronucleus occurrence was not associated with age at first coitus, number of sexual partners, multiparity, or use of hormonal contraception. These findings suggest that the mutagenic effect of smoking occurs in cervical cells and that SIL progression is associated with an increased frequency of chromosomal damage. The data further suggest that smoking adds to the risk of progression of low-grade SIL (CIN 1). Micronucleus testing, along with the cervical cytologic smear, is recommended to monitor smokers with this type of lesion.

Hemodynamic and metabolic effects of CO2 pneumoperitoneum in an experimental model of hemorrhagic shock due to retroperitoneal hematoma.

BACKGROUND: Diagnostic laparoscopy has been used in abdominal trauma patients, although its role is not well defined. The safety of laparoscopic evaluation in trauma patients with severe intraabdominal hemorrhage has not yet been analyzed. The purpose of this study is to evaluate the hemodynamic and metabolic effects of CO2 pneumoperitoneum (COI) in hemorrhaged animals through a retroperitoneal hematoma (RH). METHODS: Twenty-two 15-20-kg mongrel dogs were monitored for systemic and pulmonary hemodynamics, inferior vena cava pressure, and arterial blood gases. After 1 h of baseline, all animals were submitted to a RH. After 45 min the dogs were randomized into two groups. Control (CTR): dogs were submitted only to a RH; pneumoperitoneum (PN): dogs were submitted to a RH and 45 min later they were insufflated to an intraabdominal pressure of 10 mmHg with medical-grade CO2 gas for 30 min. Echocardiography was performed, only in PN animals, at baseline, 45 and 60 min after RH. RESULTS: RH induced a shock condition with low, sustained levels of arterial pressure, cardiac index, left ventricular stroke index, base excess, and oxygen delivery which were further depressed following COI. Three deaths occurred in the PN group, all of them toward the end of COI. During COI, hypercapnia was observed in one animal. COI did not impair systolic function or ejection fraction. CONCLUSIONS: COI with an IAP of 10 mmHg may be deleterious in animals with hemorrhagic shock due to an intraabdominal lesion. These findings could be clinically significant in abdominal trauma patients.

Polarity of mutations in tumor-associated microsatellite instability.

Many factors have been implicated in influencing the rate of microsatellite mutations, including the length and base composition of the repeat motif, number of repeats, base composition of flanking sequences and, perhaps most importantly, degree of perfection of the repeats. The latter is of clinical relevance, since in both spino-cerebellar ataxia and fragile X syndrome, alleles with imperfect repeats appear to be much more stable than perfect ones. As yet, the relative importance of increased replication slippage and decreased mismatch repair efficiency in the preference of mutations to occur within perfect repeats has not been fully determined. D13S308E is an asymmetric trinucleotide repeat microsatellite with the sequence (CAT)3CAC(CAT)CAC(CAT)2CAC(CAT)CAC(CAT)15, thus containing two parts: an 11-repeat imperfect portion (underlined above) and a 15-repeat perfect one (bold). We sequenced eight new mutant alleles of D13S308E from three human gastric tumors with instability in this and other microsatellites. In all mutations the size variation occurred exclusively in the perfect part of the microsatellite. These results constitute direct evidence that the molecular basis of microsatellite alterations seen in normal cells is similar to those that occur in human tumors with extensive microsatellite instability. The investigation of mechanisms involved in microsatellite mutations has been handicapped by the fact that they are rare events. The microsatellite instability observed in malignant tumors provides us with a useful general system to study these mechanisms.

The use of genetic instability as a clinical tool for cancer diagnosis.

Human tumors exhibit two fundamentally important characteristics, extensive genetic alteration and clonality. Although it is still unclear to what extent tumors have an elevated mutational burden as compared with normal tissue, their clonality results in their ready detection. Thus, assaying tissues for clonal alterations at frequently mutated microsatellite loci represents a viable approach to cancer diagnosis. The most remarkable extension of this concept is that not only can cancer cells be detected in biological samples, but tumor DNA can also be directly detected in the serum or plasma of patients with some forms of cancer. This recent finding is currently being explored but may represent an important contribution to future diagnostic strategies.

Hyperthermia increases the metastatic potential of murine melanoma.

Hyperthermia, either alone or combined with radio-, immuno- or chemotherapy, can control tumor growth, but its effect on metastasis is still controversial. In the present study, we investigated the influence of hyperthermia on the metastatic potential of B16-F10 murine melanoma cells. Incubation of melanoma cells at 43 degrees C for 30 min led to a significant decrease in cell viability. About half of the cells survived the acute exposure to heat. These thermoresistant cells displayed a longer lag phase as compared to control unheated B16-F10 melanoma cells. Other parameters of cell growth such as doubling time and saturation density were equivalent in both control and thermoresistant cells. Both control and treated cells were adherent, but thermoresistant cells failed to spread during the first 48 h after heat exposure. B16-F10 cells colonize the lungs of C57BL/6J mice when injected intravenously; the number of lung colonies is a measure of the metastatic potential of injected cells. Median values of 22, 10.5 and 31 colonies per injected mouse were observed for control cells, cells heated to 43 degrees C for 30 min and thermoresistant cells, respectively, with statistically significant differences between groups (Mann-Whitney test, P < 0.02). Thus, despite its cytotoxic action, heat exposure induced the acquisition of a more metastatic phenotype in a subpopulation of B16-F10 cells.

Hyperthermia increases the metastatic potential of murine melanoma

Hyperthemia, either alone or combined with radio-, immuno- or chemotherapy, can control tumor growth, but its effect on metastasis is still controversial. In the present study, we investigated the influence of hyperthermia on the metastatic potential of B16-F10 murine melanoma cells. Incubation of melanoma cells at 43 degrees Celsius for 30 min led to a significant decrease in cell viability. About half of the cells survived the acute exposure to heat. These thermoresistant cells displayed a longer lag phase as compared to control unheated B16-F10 melanoma cells. Other parameters of cell growth such as doubling time and saturation density were equivalent in both control and thermoresistant cells. Both control and treated cells were adherent, but thermoresistant cells failed to spread during the first 48 h after heat exposure. B16-F10 cells colonize the lungs of C57BL/6J mice when injected intravenously; the number of lung colonies is a measure of the metastatic potential of injected cells. Median values of 22, 10.5 and 31 colonies per injected mouse were observed for control cells, cells heated to 43 degrees Celsius for 30 min and thermoresistant cells, respectively, with statistically significant differences between groups (Mann-Whitney test, P<0.02). Thus, despite its cytotoxic action, heat exposure induced the acquisition of a more metastatic phenotype in a subpopulation of B16-F10 cells.

Gastro-esophageal isoperistaltic bypass in the palliation of irresectable thoracic esophageal cancer.

METHODS: The authors retrospectively review 22 patients with irresectable esophageal cancer in whom an isoperistaltic substernal gastric esophagogastric bypass was performed. RESULTS: After the operation eighteen patients (82%) regained normal swallowing. Seven patients developed anastomotic stenosis that was successfully treated in six by surgery or endoscopic dilatation. Two patients evolved with cervical fistulae until their death. As a whole, there was a statistically significant improvement in swallowing capability (p = 0.0352). Seventeen patients (77%) had postoperative complications, the most common being cervical fistulae (in 13.59%), pneumonia (in 10.45%) and anastomotic stenosis (in 7.32%). Postoperative morbidity was significantly associated with preoperative diseases and ASA class III (p < 0.05). There were three postoperative deaths (14%). Postoperative mortality was significantly related to severe malnutrition and preoperative associated disease (p < 0.05). CONCLUSIONS: The conclusion is that the procedure has acceptable morbidity and mortality for the population under consideration, permitting palliation of dysphagia in the majority of cases.

[Multicentric myxoid, metachronous and synchronous and multifocal liposarcoma: report of a case]. / Lipossarcomas mixoides multicêntricos e multifocais sincrônicos e metacrônicos: relato de caso.

A case of a male patient, 66 years old, who exhibited in a period of six years many multicentric and multifocal synchronic and metachronic myxoid liposarcomas is reported. The authors made a revision of cytogenetics and DNA alterations recently identified in this type of tumor. The chromosomic alterations are represented by the translocation t(12;16) (q13;p11) and trisomy of the chromosome 8. The genic analysis revealed the presence of altered restriction fragments due to highly specific and reproducible methylation differences. In conclusion the authors suggest that the presence of the multiple tumors of this type in the same patient could be due to a common etiologic factor, not yet known, as being the initiator of this systemic illness of the fat tissue.

[Gastric epithelioid leiomyosarcoma simulating pancreatic pseudocyst. Report of a case and review of the literature]. / Leiomiossarcoma epitelióide gástrico simulando pseudocisto de pâncreas. Relato de um caso e revisão da literatura.

The authors report a case of malignant gastric leiomyoblastoma (epithelioid leiomyosarcoma) which was mistaken for a pseudocyst of the pancreas. The patient was operated several times in another hospital. At one of the operations a cystogastrostomy was performed. In november, 1989, when operated again by us, a large tumoral mass arising from the posterior gastric wall was found. The histopathological diagnosis was leiomyoblastoma of the stomach. It is concluded that the wall of a pancreatic cystic lesion should always be submitted to histologic examination in order to be excluded the possibility of a malignant neoplasm.