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Biomedical subjects

T Howard

Publications and source records attributed to T Howard.

At least 73 records · Page 4Linked to original sources
PubMed1993

Fatal cerebral gunshot wounds: factors influencing organ donation.

Patients with clinical brain death following head injury are important potential cadaveric organ donors. We analyzed our series of cranial gunshot wounds with particular attention to the frequency and patterns of organ donation after fatal injuries. Sixty-six patients with gunshot wounds to the head, including 59 with intracranial involvement (43 male, average age 26 years) were seen during a 4-year period. Injuries were limited to the head in 50 of 59 patients. Overall mortality was 66 per cent. Predictors of mortality included Glasgow Coma Scale (GCS) of six or less (93%), self-inflicted gunshot wounds (75%), and computed tomography (CT) findings of bihemispheric injury (87%) or ventricular injury (82%). Of the 39 patients who died, 28 met standard criteria for brain death, and nine of these went on to organ procurement. Thirteen families refused donation, and six patients were not harvested for reasons including old age, pregnancy, suspicion of AIDS, coroner refusal, and failure to pursue consent. Principles essential to maximal organ retrieval include: 1) Recognition that patients suffering cerebral gunshot wounds represent potential organ donors and that certain factors are predictive of mortality; 2) Critical care/trauma team approach with standardized management and timely declaration of brain death; 3) Early search for family members and prompt notification of organ procurement agencies; 4) Sensitivity to cultural issues influencing donation; and 5) Programs to increase public awareness of organ donation.

Adolescent↗
PubMed1993

Relative mitogenic activities of wild-type and retinoblastoma binding-defective SV40 T antigens in serum-deprived and senescent human diploid fibroblasts.

A novel gene transfer approach was used to investigate whether the retinoblastoma (Rb)-binding domain of simian virus 40 (SV40) T antigen is required for efficient T antigen-mediated stimulation of DNA synthesis is quiescent or senescent human embryo fibroblasts. In senescent cells, comparison between wild-type T antigen and a mutant defective in Rb binding (Glu-107-->Lys) revealed the latter to have approximately 15-fold lower activity. In contrast, comparison of wild-type and Rb- T antigens in serum-deprived quiescent cells revealed a much smaller (1.8-fold) difference. Surprisingly, an 18-fold differential could be induced by treating quiescent cells with the differentiating agent sodium butyrate. These results suggest that the role of Rb in control of the cell cycle is strongly dependent on the physiological state of the cell and the mechanism of growth arrest.

Antigens, Polyomavirus Transforming↗
PubMed1992

Clinical effects of a sorbent suspension dialysis system in treatment of hepatic coma (the BioLogic-DT).

Fifteen patients with acute deterioration of liver function, high serum ammonium, and an average coma level of 3.9 were identified. Eleven of the patients were on respirator support, and eleven had kidney failure pursuant to the liver failure. The patients were treated for 8-12 hours daily with the BioLogic-DT system, in which membranes of a cellulosic plate dialyzer actively pump blood through a single access at over 200 ml/min, and the dialysate contains a suspension of powdered activated charcoal (300,000 square meters surface area) and cation exchanger (160 meq capacity). No anticoagulant was used. In spite of the declining condition of the patients prior to treatment, there was a statistically significant improvement in neurologic status during individual treatments, and a positive trend over 1-12 (average four) daily treatments. Four patients recovered liver function and another four improved enough to receive a liver transplant operation. The BioLogic-DT system appears to be safe in treatment of patients with hepatic insufficiency and coma. The neurologic improvement of these patients indicates that many toxins of hepatic failure are dialyzable across cellulosic membranes and bound by charcoal.

Acute Disease↗
PubMed1991

Morphology and mobility of oyster hemocytes: evidence for seasonal variations.

Hemocytes of Crassostrea virginica were video recorded and tracked to determine their locomotive rates and to assign these rates to Wright-stained morphological variants. From 24 oysters examined in January, February, March, and May, 1571 hemocytes were video recorded, identified, and their rate of locomotion (ROL) measured. Granulocytes (three types) and agranulocytes (one lymphoid and three nonlymphoid types) were recognized. Focusing on 15 oysters in March and May, 20,318 hemocytes were counted from duplicate slides to verify the classification and to show that predominant hemocytes vary greatly between samples and among individual oysters, yet population differences can be detected. Measured rates of locomotion indicate that the granulocyte subpopulation moved significantly faster (3.3 microns/min) than the agranulocyte subpopulation (0.7 microns/min) because most (81%) agranulocytes were not mobile. Of the mobile hemocytes, granulocytes were also significantly faster (4.8 microns/min vs. 3.5 microns/min, P less than 0.0001), and basophilic granulocytes (BASOs) were the most active and abundant cell type. Examination of monthly percentages of cells and ROL indicates, however, that granulocyte dominance and ROL are not invariable. Granulocyte percentages of more than 60% in January, February, and March decreased to 32% in May, and BASO dominance was reduced to 15%. Further, percentages of mobile granulocytes decreased from greater than 65% in January, February, and March to 50% in May. ROL for all cells decreased from greater than 2.3 microns/min in these months to 1.0 microns/min in May. The fewer mobile hemocytes tracked in May had significantly (P less than .05) lower average ROL (4.0 microns/min) than those in January and March (4.7 microns/min each). Agranulocytes increased in May due to an increase in nonlymphoid cells.

Animals↗
PubMed1990

Gelsolin-actin interaction and actin polymerization in human neutrophils.

The fraction of polymerized actin in human blood neutrophils increases after exposure to formyl-methionyl-leucyl-phenylalanine (fmlp), is maximal 10 s after peptide addition, and decreases after 300 s. Most of the gelsolin (85 +/- 11%) in resting ficoll-hypaque (FH)-purified neutrophils is in an EGTA resistant, 1:1 gelsolin-actin complex, and, within 5 s after 10(-7) M fmlp activation, the amount of gelsolin complexed with actin decreases to 42 +/- 12%. Reversal of gelsolin binding to actin occurs concurrently with an increase in F-actin content, and the appearance of barbed-end nucleating activity. The rate of dissociation of EGTA resistant, 1:1 gelsolin-actin complexes is more rapid in cells exposed to 10(-7) M fmlp than in cells exposed to 10(-9) M fmlp, and the extent of dissociation 10 s after activation depends upon the fmlp concentration. Furthermore, 300 s after fmlp activation when F-actin content is decreasing, gelsolin reassociates with actin as evidenced by an increase in the amount of EGTA resistant, 1:1 gelsolin-actin complex. Since fmlp induces barbed end actin polymerization in neutrophils and since in vitro the gelsolin-actin complex caps the barbed ends of actin filaments and blocks their growth, the data suggests that in FH neutrophils fmlp-induced actin polymerization could be initiated by the reversal of gelsolin binding to actin and the uncapping of actin filaments or nuclei. The data shows that formation and dissociation of gelsolin-actin complexes, together with the effects of other actin regulatory proteins, are important steps in the regulation of actin polymerization in neutrophils. Finally, finding increased amounts of gelsolin-actin complex in basal FH cells and dissociation of the complex in fmlp-activated cells suggests a mechanism by which fmlp can cause actin polymerization without an acute increase in cytosolic Ca++.

Actins↗
PubMed1988

A structured diagnostic interview for identification of primary alcoholism: a preliminary evaluation.

Forty alcoholic inpatient men were used to evaluate the test-retest reliability and the validity of a new structured diagnostic interview. The Alcohol Research Center (ARC) Intake Interview was constructed from the Schedule of Affective Disorders and Schizophrenia (SADS) parts I and II and from the Diagnostic Interview Schedule family history section by extracting information on diagnoses most likely to be seen in alcoholic patients and by expanding the data set with questions relevant to alcohol and drug use. The test-retest reliability for patients' primary and secondary diagnoses included a kappa of 1.00 for the comparison of interviewers A and B (100% agreement) and of .76 for interviewers A and C. The validity of ARC Intake Interview patient diagnoses as compared to the SADS demonstrated an overall agreement between 91 and 100%. Reliabilities for labeling of families as positive or negative for specific illness in any first-degree relatives revealed a kappa of 1.00; validities on family diagnoses ranged from 77 to 100%, with the ARC Intake Interview identifying more illness in families than the SADS. Although further evaluation of the ARC Intake Interview is needed, this instrument is recommended to investigators attempting to evaluate the clinical course and treatment needs among alcoholics, especially those patients presenting with multiple diagnoses.

Adult↗
PubMed1987

Hormonal regulation of gluconeogenesis in cultured proximal tubular cells: role of cytosolic calcium.

Gluconeogenic competence of primary cultures of canine renal proximal tubular cells has been examined. Cells grown in 5 mM glucose media or in glucose-free media exhibited pyruvate-stimulated glucose production, as opposed to cells grown in 20 mM glucose media. By 72 h after the last media change, confluent cells grown in 5 mM glucose medium turn from a predominantly glycolytic to an oxidative type of metabolism. By this time, glucose production exhibited pH, 3-mercaptopicolinate, and insulin sensitivity. Parathyroid hormone, angiotensin II, and phenylephrine stimulated glucose production in a nonadditive fashion. Single-cell cystolic Ca2+ measurements using microspectrofluorometric techniques revealed that all three hormones elicited Ca2+ transients in proximal tubular cells. Ionomycin stimulated glucose production by proximal tubular cells, suggesting that Ca2+ transients could represent a sufficient stimulus for glucose production. When hormone-induced Ca2+ transients were curtailed by a pretreatment with the membrane-permeant Ca2+ chelator, Maptam, hormonal stimulation of glucose production was abolished, suggesting that Ca2+ transients represent not only a sufficient, but a necessary event in the stimulation of glucose production by these hormones.

Adenosine Triphosphate↗
PubMed1987

Vaginoplasty.

Explore the source record for details and available documents.

Adolescent↗
PubMed1986

Viral and bacterial organisms associated with acute pharyngitis in a school-aged population.

To investigate the causes and clinical characteristics of acute pharyngitis among school-aged children (4 to 18 years), we obtained throat cultures for respiratory viruses, Mycoplasma pneumoniae, group A streptococcus, and Chlamydia trachomatis from 320 patients with sore throat and 308 controls without respiratory complaints. The study was conducted from January to April 1985 in a private pediatric practice in central New York State. Sixty percent of the patients and 26% of the control subjects had positive cultures for at least one organism. Forty percent of patients had positive cultures for group A streptococcus, compared with 11.9% of the controls. Fifty (16%) patients had positive viral cultures, compared with eight (2.6%) controls; the predominant viral isolate was influenza A Philippines. Patients infected with influenza A were significantly more likely to complain of cough and hoarseness, and were less likely to have pharyngeal exudate or tender cervical adenopathy, than were patients who had positive cultures for group A streptococcus. Although 49 (15.8%) patients with acute pharyngitis had cultures positive for M. pneumoniae, 53 (17.6%) asymptomatic controls were also had M. pneumoniae-positive cultures. Thus detection of M. pneumoniae in the throat of school-aged children with pharyngitis may not be sufficient to establish a diagnosis of disease caused by this organism. C. trachomatis was not isolated from any patient or control.

Acute Disease↗
PubMed1985

X-ray pelvimetry in a breech protocol: a comparison of digital radiography and conventional methods.

X-ray evaluation of the pelvis plays a pivotal role in selecting term breech presentation for a possible trial of labor. Even minimal degrees of disproportion may have disastrous consequences for the aftercoming head. Our evaluation of x-ray pelvimetry by computerized tomography scanning suggests it is probably more accurate than conventional methods, with a concomitant decrease in fetal x-ray exposure.

Breech Presentation↗
PubMed1985

Plasma dextran levels after abdominal instillation of 32% dextran 70: evidence for prolonged intraperitoneal retention.

Postoperative ascites in patients receiving intraperitoneal dextran 70 may result from slow absorption. We tested this by instilling 250 ml of dextran 70 into the peritoneal cavity of patients undergoing tuboplasty. Serum dextran levels were undetectable until 24 hours after operation and rose during the next 4 days. Ascites in patients with intraperitoneal dextran 70 results from third spacing in response to the persistent osmotic load.

Absorption↗
PubMed1983

Clinical and pathologic correlations in traumatic spondylolisthesis of the axis.

Traumatic spondylolisthesis of the axis ("hangman's fracture") occurred in an 89-year-old man who died of unrelated causes. Postmortem examination of the cervical spine revealed a correlation between the anatomic lesion and clinical treatment and prognosis. Traumatic spondylolisthesis of the axis has a high potential for union because it usually occurs through the superior facet joint, in an area of well vascularized spongy cancellous bone. Fracture through the thin cortical bone of the pars interarticularis, conversely, is predisposed to the development of a nonunion and, hence, may explain this condition. While hyperextension with compression or distraction appears to have caused the injury in some cases, axial compression with flexion was the cause in this case.

Aged↗