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Biomedical subjects

R Acosta

Publications and source records attributed to R Acosta.

30 records · Page 2Linked to original sources
PubMed1993

Distal radio-ulnar ligament motion during supination and pronation.

The dorsal and palmar distal radio-ulnar ligaments (DRUL) play an important role in the stability of the distal radio-ulnar joint (DRUJ). Various authorities, however, hold opposite opinions regarding DRUL motion during DRUJ pronation and supination, thus implying opposite techniques for reconstruction of the unstable DRUJ. With the hypothesis that relative displacement would increase in the dorsal DRUL during pronation and would increase in the palmar DRUL during supination, measurements were made of the relative DRUL displacement with a Hall-effect displacement transducer during DRUJ pronation and supination in six fresh cadaver wrists. The hypothesis was confirmed that the dorsal radio-ulnar ligament undergoes relative displacement during pronation, while the palmar radio-ulnar ligament undergoes relative displacement during supination.

Aged↗
PubMed1992

Sickle and thalassemic erythroid progenitor cells are different from normal.

Blood erythroid progenitors (BFU-E) from patients with sickle and thalassemic syndromes were compared with those from normal individuals. The day of maximal colony formation in methyl cellulose was slightly later in the cultures from the patients with hemoglobinopathies than in the normal cultures. The number of colonies/100,000 mononuclear cells was similar in all cultures on day 13, but was higher in the hemoglobinopathy cultures on the day of maximal growth. The number of BFU-E/mL of blood was significantly higher than normal at all times in both sickle cell anemia and thalassemia. The proportional synthesis of gamma globin was twice normal in all sickle cultures, and 4 times normal in those from beta+-thalassemia. Hemin and interleukin-3 increased the numbers of erythroid colonies in all cultures, but did not consistently alter the globin synthesis patterns. Each progenitor population has a unique pattern in terms of time course, number of BFU-E, and level of gamma globin synthesis. These features indicate distinct types of BFU-E, or differences in accessory cells, or both, which distinguish blood-borne erythropoiesis in normals and those with hemoglobinopathies.

Adolescent↗
PubMed1991

Management of auto-emasculation in the psychotic state.

We report 2 cases of self-inflicted penile amputations, which offered differing surgical options and contrasting surgical results due to varying time delays. In 1 case repair was done immediately, while repair in the other case was delayed by 3 days due to the psychotic state of the patient. The psychiatric backgrounds of such episodes are discussed, as well as the techniques of repair and reconstruction.

Adult↗
PubMed1990

Aggressive digital papillary adenocarcinoma.

Aggressive digital papillary adenocarcinoma is a rare neoplasm of eccrine sweat gland origin. An acral location and a high recurrence rate are characteristic features. Its histopathologic features are distinctive, and the tumor expresses carcinoembryonic and S-100 protein antigens. We demonstrated immunoreactivity of the tumor to ferritin antibody, a new immunohistologic marker for sweat gland malignancies.

Adenocarcinoma, Papillary↗
PubMed1987

Stringency in the absence of ppGpp accumulation in Rhodobacter sphaeroides.

Leucine deprivation of either phototrophically or chemotrophically growing cells of Rhodobacter sphaeroides resulted in a restriction in the continued accumulations of cellular RNA, phospholipids, and protein. Phototrophically growing cells also displayed restrictions in the accumulations of cellular carotenoids and bacteriochlorophyll. Leucine deprivation, however, did not provoke the accumulation of cellular ppGpp or alter the steady-state levels of ppGpp, ATP, or GTP in cells of R. sphaeroides.

Guanine Nucleotides↗
PubMed1984

A 37 X 10(3) molecular weight plasmid-encoded protein is required for replication and copy number control in the plasmid pSC101 and its temperature-sensitive derivative pHS1.

Nucleotide sequences were determined for a region essential for autonomous replication and partitioning of pSC101, a plasmid whose replication is dependent on the Escherichia coli dnaA gene product. The essential replication region contains one long coding sequence, rep101 , for a protein composed of 316 amino acids, and a polypeptide approximately 37 X 10(3) Mr in size was identified as the rep101 gene product. rep101 is preceded by two inverted repeat sequences, three directly repeated sequences and a region of high A + T content containing a sequence similar to the E. coli oriC consensus sequence. Because the lesions in seven replication-deficient insertion mutants, four mutants with increased copy number and one temperature-sensitive replication mutant occur within rep101 , the rep101 gene product must control pSC101 replication and copy number. par, a region adjacent to the replication region, which functions in stable plasmid inheritance, contains several inverted repeat sequences.

Autoradiography↗
PubMedDate not supplied

Relationship between morphology and motion characteristics of human spermatozoa in semen and in the swim-up sperm fractions.

In this study, the authors evaluated the morphology pattern and motion characteristics of human spermatozoa before and after swim-up separation. Samples were divided into two, morphologically different groups according to the percentage of normal sperm forms assessed by the strict criteria of the Norfolk laboratory: "good"(G) and "poor" (P) prognosis patterns. The percentages of normal forms, slightly abnormal forms, and severe head defects were significantly different in the two groups. Motile characteristics were analyzed by a computerized semen analyzer with constant parameter settings. Before swim-up there were no significant differences in semen volume, percentage of neck and tail defects, concentration, or percentage of motility and linearity, but the mean velocity was higher in group G. After swim-up the percentage of motility, total number of motile cells, and recovery rate were higher for group G, and the incidence of severe head defects correlated negatively with the percentage of cells with a velocity of greater than 80 microns/sec. The results suggest that patients with a high incidence of sperm head defects have impaired original velocity, and swim-up selects for velocity as well as normal forms and motility. Although motility and velocity improved substantially after swim-up, the recovery rate and percentage of motility were significantly lower in the P group.

Cell Separation↗