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Biomedical subjects

S Medina

Publications and source records attributed to S Medina.

At least 73 records · Page 4Linked to original sources
PubMed1991

Porphyria cutanea tarda associated with autoimmune hypothyroidism, vitiligo and alopecia universalis.

The aetiology of porphyria cutanea tarda (PCT) has not been elucidated, but the possibility of an autoimmune mechanism has been proposed. We report a case of an unknown clinical combination of PCT with autoimmune hypothyroidism, alopecia universalis and vitiligo with thyroid and parietal cell circulating antibodies. This is highly suggestive of underlying autoimmune damage in this patient.

Adult↗
PubMed1984

Colonic surgery. The splenic connection.

Colonic resections, particularly those that require mobilization of the splenic flexure, occasionally will lead to injury of the spleen. Under these circumstances, the abdominal surgeon has traditionally considered incidental splenectomy to be the only safe alternative. Currently, a better understanding of splenic physiology and its role in sepsis prevention has reversed this trend. These efforts to preserve splenic function have resulted in various options available to the surgeon, herein reviewed. The results obtained in 36 general surgical patients with splenic injuries suggest that the salvage of the spleen is a safe alternative. In situations where salvage is impossible, the surgeon can resort to omental autotransplantation of the removed spleen, a recently described technique of appealing simplicity. The results obtained with this procedure in 23 other patients are presented.

Colon↗
PubMed1982

Prophylactic inferior vena cava clipping in colonic surgery.

Incidental prophylactic inferior vena cava clipping (IVCC) has been used in 30 patients undergoing colonic operations. The results obtained compare quite favorably with other methods of preventing postoperative pulmonary embolism (PE). This procedure would be justified in patients with a postoperative PE risk greater than 5 to 10 per cent. Practical criteria to identify this group of patients are presented, and the value of utilizing a risk profile is emphasized. There is no mortality from the procedure itself, and the morbidity was limited to lower-extremity edema in three patients who otherwise could have been expected to develop PE. The edema lasted two months in one patient and cleared rapidly in the other two. Attesting to the procedure's effectiveness, there were no cases of recurrent PE. Caval partition is an appealing mode of prophylaxis in high-risk patients because of its safety, efficacy, and permanence.

Aged↗
PubMed1975

Effect of nonspecific stimulation on the defense mechanisms of inbred mice.

Acquired resistance to facultative intracellular parasites was investigated in C57BL/6J inbred mice susceptibe to Salmonella typhimurium but inherently resistant to Listeria monocytogenes and in A/J inbred mice which showed the reverse relationship. A/J but not C57BL/6J mice were protected against S. typhimurium challenge by S. typhimurium phenol vaccine, S. typhimurium purified RNA, or L. monocytogenes purified RNA. C57BL/6J but not A/J could be protected against L. monocytogenes challenge by L. monocytogenes phenol vaccine, S. typhimurium RNA, or L. monocytogenes RNA. Yeast RNA, calf thymus RNA, BCG and poly (I:C) protected A/J against Salmonella and C57BL/6J against Listeria challenge. Enumeration of viable organisms in the RNA and BCG-stimulated animals after challenge indicated that macrophage activation had probably taken place. The RNA-elicited protection was long lasting and waned after about 60 days. Enhanced resistance to S. typhimurium and L. monocytogenes can be stimulated by nonliving substances bearing no known antigenic relationship to the pathogen. Enhanced resistance is elicited only in the host with a background of inherent resistance to the specific pathogen.

Animals↗
PubMedDate not supplied

Cytogenetic and molecular characterization of a congenital mesoblastic nephroma.

A newborn baby boy was diagnosed with the mixed form of congenital mesoblastic nephroma (CMN) representing both classic and cellular histology features in the renal tumor. Additionally, the patient had skin and bone lesions consistent with multifocal involvement of a generalized infantile fibromatosis (IFS). Both skin and bone lesions were distinctly different from CMN and did not represent metastasis. The primary tumor cell line (MCH-MN-1), established from the resected right kidney tumor, had a diploid DNA content. Cytogenetic studies revealed deletion on the long arm of chromosome 3 (q21q24) and duplication on the short arm of chromosome 11 (p15). MCH-MN-1 cells expressed ETV6-NTRK3 gene fusion transcripts, characteristic of cellular and mixed forms of CMNs. The cells had high p21 and low Bax mRNA expression in the reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The high level of proliferative marker (Ki67) mRNA expression correlated well with the pluripotent nature of MCH-MN-1 in tissue culture (cell doubling time = 12.4 h). Our results showed that MCH-MN-1 might be a good model cell line for investigations on mesoblastic nephroma.

Chromosome Deletion↗
PubMedDate not supplied

Prenatal and perinatal lead exposures alter acoustic cry parameters of neonate.

We performed acoustic analyses on cries elicited from a subset of healthy babies born to the Mexico City Prospective Lead Study at 2 days (n = 75), 15 days (n = 176), and 30 days (n = 166). Lead was measured in maternal blood every 8 weeks during pregnancy from week 12 to delivery and in umbilical cord (1-38 micrograms/dL, 0.05-1.84 mumol/L). Percent nasalization and number of cries decreased in babies born to mothers with higher lead levels in the last two trimesters while median fundamental frequency increased in babies born to mothers with higher lead at 12 weeks of pregnancy, and with higher cord lead in multiple regression analysis. Decreased percent nasalization was related to increased brainstem auditory evoked response latencies and interpeak intervals in a subset of the sample. The results suggest an effect of gestational exposure to lead on apparatus innervated by cranial nerves and/or lead effect on cry mediated by lead-altered auditory function. Altered baby cry and auditory function associated with lead might contribute to developmental delays by affecting early communication between caretaker and baby.

Acoustics↗
PubMedDate not supplied

Effect of polyethylene particles on human osteoblastic cell growth.

In this study, we have analyzed the direct effect of ultrahigh molecular weight polyethylene (polyethylene) on the osteoblastic cell growth in primary cultures. The cells were cultured from human bone samples obtained during reconstructive joint surgery. When cell cultures reached confluence (4-6 weeks) they were separated into three subcultures. One subculture was without particle addition (plain culture). In the other two subcultures, polyethylene or alumina was added. Two different sizes of particles were used, <80 and <160 microm. The subcultures were incubated until confluence. Proliferation of each subculture was measured by cell counts after 3, 6, 9 and 13 days, and the area under the curve (AUC) was calculated. Polyethylene particles of <160 microm induced a decrease in growth, whereas alumina of the same size did not. Polyethylene and alumina particles of <80 microm induced an inhibition in the osteoblastic cell growth; <80 microm polyethylene induced a higher inhibition than alumina of the same particle size. In conclusion, we have observed a direct effect of polyethylene on osteoblastic cell growth. This study shows that polyethylene may decrease the growth rate of human osteoblastic cells in primary cultures. Smaller particles produce a more marked reduction.

Biocompatible Materials↗
PubMedDate not supplied

Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities.

PURPOSE: The purpose of this work was to assess the performance of helical CT angiography (CTA) in the diagnosis of injuries to large arteries of the extremities. METHOD: We performed helical CTA on 45 consecutive patients referred for conventional angiography for evaluation of suspected arterial injuries after sustaining trauma to the extremities (13 upper, 32 lower). Two radiologists interpreted the helical CTA studies independently. Diagnostic performance parameters evaluated included sensitivity, specificity, receiver operating characteristic (ROC) curves, and interobserver agreement (kappa statistics). Conventional angiography was used as the standard of reference for determination of final diagnoses. RESULTS: Forty-three of 45 patients (96%) had diagnostic helical CTA examinations. Final diagnoses in these 43 patients were arterial occlusion (n = 7), partial obstruction (n = 3), pseudoaneurysm (n = 5), arteriovenous fistula (n = 1), pseudoaneurysm and arteriovenous fistula (n = 3), and normal findings (n = 24). Sensitivity and specificity were 90% [95% confidence interval (CI), 80-99] and 100% (95% CI, 99-100), respectively, for Reader 1 and 100% (95% CI, 99-100) and 100% (95% CI, 99-100), respectively, for Reader 2. ROC curve analysis revealed high diagnostic performance, with areas under the curve of >0.9 for both readers. Interobserver agreement was 0.9. CONCLUSION: The diagnostic performance of helical CTA for detection of major injuries of large arteries of the extremities is high.

Adolescent↗
PubMedDate not supplied

[A review of original papers that analyze the effects of air pollution on mortality, 1994-1998].

The different studies published and indexed in Medline and in the Spanish Medical Index (IME) from 1984 up to 1998 (IME: 1971-1996) are reviewed. To start with, an assessment was made of the number of publications put out which have to do with the impact of pollution on human health as well as the percentage thereof which analyze the mortality as a health indicator. Afterward, the original works published within the January 1994-June 1998 period were reviewed in detail. Most of the original articles are combined time series studies which analyze, on a single-day basis, the relationship between the levels of pollution and the mortality for non-accidental causes. Other original articles were also summarized based on an approach other than the time series one, highlighting different cohort studies which relate the levels of pollution to the mortality on an individual level and which confirm the findings of prior ecological studies. The pollutants analyzed most often are the different types of particles, although studies are also common regarding the impact of sulfur dioxide, nitrogen dioxide, ozone and carbon monoxide. The method of analysis most used is the Poisson regression, into which different confusion variables bearing an impact thereon such as seasonality and tendency, temperature and relative humidity and day of the year are basically added. In the studies reviewed, the positive significant findings prevail, being consistent especially for particles, which is the pollutant most analyzed. The articles studying other pollutants, although fewer in number, also indicate a significant relationship between pollution levels and the mortality.

Air Pollutants↗