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Biomedical subjects

J Romero

Publications and source records attributed to J Romero.

At least 19 recordsLinked to original sources
PubMed1992

Peripheral mechanical loading and the mechanism of the tremor of chronic alcoholism.

The tremor of chronic alcoholism, although clinically similar to essential tremor, has been considered a distinct syndrome. Its underlying mechanism was analyzed in five patients (none in the acute stages of alcohol withdrawal) hospitalized in an alcohol detoxification program. All five patients performed tracking tasks in which they pursued a linearly moving "target" light with a response light that they controlled by flexion-extension activity of the wrist. Stationary and dynamic targets were used with both isometric and unconstrained wrist mechanical interfaces. Frequency, torque, and displacement tremor characteristics were examined under varying inertial loading or isometric voluntary torque conditions. Two simultaneous tremor components were present in all patients: a prominent 4- to 7-Hz low-frequency peak and a smaller-amplitude 9.4- to 9.6-Hz high-frequency peak. As the inertia of the hand was augmented during unconstrained tasks, the low-frequency peak decreased, while the high-frequency peak was unaffected. As required voluntary effort was increased during isometric testing, the amplitude of the low-frequency peak increased. These findings suggest that the low-frequency peak represents the significant pathologic component of the tremor of chronic alcoholism and that it has a biomechanical reflex mechanism similar to that of the lower-amplitude normal physiologic tremor.

Adult↗
PubMed1992

The nucleotide sequence and genome organization of the RNA2 and RNA3 segments in broad bean mottle virus.

Complete nucleotide sequences of broad bean mottle virus (BBMV) genomic RNAs 2 and 3 were determined. They consist of 2811 and 2293 nucleotides, respectively. Both RNAs are caped and, unlike in other tricornaviruses, both initiate with an A residue. BBMV RNA2 is monocistronic and encodes an 815 amino acid 2a protein, whereas RNA3 is dicistronic, encoding for a 295 amino acid 3a protein and for the 190 amino acid coat protein. A central, 423 amino acid 2a protein core region is highly homologous among the three bromoviruses, whereas both N- and C-termini are more heterologous. Most of the homologies among 3a proteins are concentrated within the N-termini two-thirds of the molecule that is predominantly hydrophobic, whereas the C-terminal one-third contains a large number of charged amino acids. The homologies among coat proteins are clustered within several mostly hydrophobic, or neutral, domains. The 5' noncoding region of the RNA2 has 110 nucleotides, whereas that of RNA3 contains 330 nucleotides. As in cowpea chlorotic mottle virus, but unlike in Brome mosaic virus, the 5' noncoding region includes subgenomic promoter-like sequences. The BBMV RNA3 intercistronic region also has subgenomic promoter sequences and contains a long poly(A) stretch. At the 3' end, BBMV RNAs 2 and 3 have 257 and 236 noncoding nucleotides, respectively.

Base Sequence↗
PubMed1992

Bladder wash cytology and flow cytometry for the diagnosis of transitional cell carcinoma of the urinary bladder.

The role of bladder wash (BW) cytology and flow cytometry in the diagnosis of low-grade transitional cell carcinoma (TCC) of the bladder is yet to be demonstrated. We have studied a series of BW specimens by both conventional cytology and flow cytometry: there were 16 BW from patients with histologically proven TCC and 14 BW from patients with clinical suspicion of tumor or under follow-up for previous TCC in which no evidence of tumor was found by cystoscopy and multiple biopsies. As control group, 21 BW were studied from patients undergoing cystoscopy for causes other than TCC. In conclusion, the conventional cytologic study of BW specimens was highly sensitive for grade II-III TCC, but missed most grade I TCC; flow cytometric analysis did not improve significantly the detection rate in low-grade TCC.

Carcinoma, Transitional Cell↗
PubMed1992

MHC class I antigen expression is inversely related with tumor malignancy and ras oncogene product (p21ras) levels in human breast tumors.

MHC class I antigens participate in the immune response by presenting peptides to CD8+ cytotoxic T cells. Decreased expression of these antigens in tumor cells may contribute to an evasion of immune system and consequently to enhanced tumor growth. However, not all tumors expressing low levels of HLA antigens show increased malignancy, probably as a result of the differential activity of the oncogenes involved in malignant transformation. The ras family of cellular oncogenes is one of the most frequently detected families of transformation-inducing genes in human solid tumors. The aim of this work is to study the expression of MHC antigens and the ras oncogene product, p21ras, in 60 primary breast tumors in order to define its clinical significance in tumor progression. HLA antigen expression and p21ras levels were measured on breast tumors using immunohistochemistry methods and enzymoimmunoassay, respectively. The results demonstrate that more invasive tumors have both a decreased expression of HLA class I antigens and higher levels of p21ras protein expression than less aggressive tumors. These findings indicate that the capacity of breast cancers to grow and metastasize is related to low levels of MHC class I antigens and enhanced p21ras expression, thus supporting the involvement of MHC and ras oncogenes in breast tumor malignancy.

Breast Neoplasms↗
PubMed1992

[New epidemic outbreak of cholera in Lima].

We report a new outbreak of cholera on the beginning of last Summer (Dec. 91 and Jan 92). Were 281 patients, 63% male and 36% female, treated in our Cholera Unit of treatment; all of them coming from marginal-urban populations. There was a rate of lethality of inpatients of 0.46% and a mortality of 0.25% over the total of patients that we saw in our hospital; on this summer the outbreak is early and greatest than the summer of 1991. We can conclude that because of epidemic behavior during the whole 1991 and in the time elapsed of 1992, Peru has become an endemic zone of this new disease, while the current epidemiologic settings stay unchanged.

Cholera↗
PubMed1991

[Neuroepithelial tumors in the pediatric population].

We have studied the neuroepithelial tumors in childhood, about their epidemiological, clinical and histological aspects, the macroscopic tumoral structure and the findings obtained by magnetic resonance imaging. We stress the differential diagnosis features among the various tumoral types, based on bibliography and our own clinical experience.

Astrocytoma↗
PubMed1991

[Normal myelination patterns].

The MR images obtained of brain during the process of myelination taking place from birth to 2 years of age are analyzed. Basically, the study focuses on the changes in signal intensity experienced by the elements of the brain in the different sequences, consisting in an increase (T1 weighted sequence) or decrease (T2 sequences) in the signal. The chronological evolution of these changes is compared with the classic myelination pattern, described prior to the development of MR, based on necropsies. Also assessed were the progressive changes in the signals of the gray and white matter, reflecting their hydric contents, throughout the period of maturation of the brain structures. It is concluded that MR imaging is presently the diagnostic method of choice in the monitoring of myelination. MR spectroscopy studies offer important perspectives for assessment and follow up of this process from the metabolic point of view.

Aging↗
PubMed1990

[Evaluation of an agglutination method of latex particles sensitized for the detection of vaginal candidiasis].

We assayed clinically and experimentally a rapid method for detection of Candida in vagina by slide latex agglutination test (SLA). A total of 50 vaginal swabs from women with clinical evidence of candidiasis were examined for yeast by microscopical examination, mycological culture and compared with the Candida antigen test. We also studied experimentally the sensibility of the SLA test. We found better results with SLA than microscopy for rapid diagnosis. Of the women with certain vaginal candidiasis, 60% were diagnosed by microscopy and 100% by SLA. SLA provided similar information than culture, but is faster and the clinician can use its information choosing the appropriate antifungal treatment.

Candida↗
PubMed1990

Characterization and complementation of a cephalosporin-deficient mutant of Streptomyces clavuligerus NRRL 3585.

We have characterized a mutant of Streptomyces clavuligerus NRRL 3585 which is almost completely blocked in cephalosporin biosynthesis and exhibits depressed activities of both the delta(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (ACV) synthetase and cyclase enzymes of the cephalosporin pathway. A wild-type DNA region was cloned which partially restores antibiotic production, ACV synthetase and cyclase activities to this mutant. The recombinant plasmid exhibits a variable copy number in different transformants. Hybridization experiments indicate that sequences homologous to the cloned region are present in various beta-lactam-producing Streptomyces spp. but absent in species which are not known to produce this class of antibiotics. Furthermore, the chromosomal copy of the cloned region lies in close proximity to a gene coding for the isopenicillin N synthase gene of the cephalosphorin pathway.

Bacterial Proteins↗
PubMed1990

Infectious endocarditis in children.

With the object of analyzing current characteristics of infectious endocarditis (IE) in children, we carried out a retrospective study of 23 cases of IE in children under 15 years of age seen at the Hospital Ramón y Cajal in Madrid (Spain) between 1977 and 1985. The incidence was high (1.3 cases per 1000 children admitted). The male/female ratio was 2:1. Eight patients were under 2 years of age and 15 over 2 years, the majority being adolescents. The two groups presented marked etiological and prognostic differences. Congenital heart disease was the predisposing factor in 20 of the 23 cases. Streptococcus viridans (nine cases) and Staphylococcus aureus (eight cases) were the most frequent organisms. Fourteen cases were on a native valve and nine were secondary (seven of these on prosthetic patches). In spite of advances in therapy, IE continues to be a severe illness: the mortality rate in our series was 26%. Factors associated with a poor prognosis were: age less than 2 years, Staphylococcus aureus as the causative agent, and the presence of prosthetic material.

Adolescent↗
PubMed1990

[Prevalence of viral hepatitis B in a group of prostitutes living in Chimbote (Peru)].

We have studied HBV markers in 56 sera from 56 prostitutes who were registered to the Health Ministry Zonal Hospital of Chimbote on October, 1987. We used micro-Elisa solid phase technics to study the HBs Ag, HBs Ab, HBc Ab (Total IgG) and HBe Ag markers. From them, 89.3% were positive to any marker: 5.4% were asypmtomatic carriers and 83.9% had markers related to past HBV (immunity). In conclusion, this data shows clearly, that the prostitutes represent an important risk group for the transmission of the Hepatitis Type B virus to people who maintains sexual relations with them. The HBc Ab was the best marker to detect HBV antibodies, that did it in 95.7%.

Adolescent↗
PubMed1990

[Botulism: the first epidemic outbreak in Peru].

The first occurrence of Botulism described in Perú took place in Huancayo city, in November 1988. Twelve persons became ill, two of them died. All of them ate "salchipapas" a very popular meal in the country done with fried potatoes, hot dogs, eggs and dressed with mayonnaise) in a restaurant near their working place. Six of the twelve patients were immediately taken to Lima and admitted in Edgardo Rebagliati Martins National Hospital from the Social Security Peruvian Institute, and treated by the International Medicine Department. We studied five of the six patients; they all had similar symptoms and signs, specially neurological and gastrointestinal ones. Their serological specimens were positive for type B botulin toxin. Clinical, epidemiologic, electromyographic and laboratory findings supported the diagnosis of the first outbreak of Botulism in Perú.

Adult↗
PubMed1989

[Successful treatment of a cheilothorax in lymphangiomatosis of the ribs (Gorham-Stout syndrome)].

In 1955 Gorham and Stout described the syndrome of lymphangiomatosis of the bone resulting in widespread monofocal osteolysis in the skeletal system. The results of therapy are difficult to evaluate as the disease may come to a sudden stand-still. If angiomatosis arises near the thorax, pleural effusion occurs due to simultaneous involution of the thoracic duct. This complication has a fatal outcome and effective treatment is required. A case is reported in a 61-year-old male in whom radiotherapy of the lower ribs on the right thorax reduced the lymphangiomatous swelling and healed the chylothorax.

Bone Neoplasms↗