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Biomedical subjects

G Hammond

Publications and source records attributed to G Hammond.

At least 55 records · Page 3Linked to original sources
PubMed1988

Corticosteroid binding globulin, testosterone-estradiol binding globulin, and androgen binding protein belong to protein families distinct from steroid receptors.

The cDNA nucleotide sequences and the deduced amino acid sequences of human corticosteroid binding globulin (hCBG), human testosterone-estradiol binding globulin (hTeBG), and rat androgen binding protein (rABP) were determined. Studies of the steroid binding sites suggest they are toward the carboxy-terminus in hTeBG and rABP and more central in hCBG. hCBG has remarkable sequence homology with members of a superfamily whose functions have diverged; these include thyroxine-binding protein, serine protease inhibitors, egg white proteins, and angiotensinogen. hTeBG and rABP have a 68% amino acid sequence identity. Hybridization studies suggest that hTeBG is probably even more closely related, if not identical, to hABP. The carboxy-terminal sequences of hTeBG and rABP are also similar to that of protein S, a vitamin-K-dependent clotting factor. There were no nucleotide or amino acid sequence homologies between hCBG, hTeBG, or rABP and other steroid binding proteins such as steroid receptors, albumin, alpha-fetoprotein, and vitamin D binding protein. We conclude that the "extracellular steroid binding proteins" and steroid receptors do not appear to have descended from a common ancestor.

Amino Acid Sequence↗
PubMed1988

Hand asymmetries in interresponse intervals during rapid repetitive finger tapping.

Interresponse intervals (IRIs) were recorded as 8 right-handed male subjects tapped a key separately with the index finger of each hand as fast as possible for twenty 10-s runs. Frequency distributions of the IRIs produced by each hand showed that the shorter mean IRI that is usually reported for preferred-hand tapping is a result of a systematic production of shorter IRIs by the preferred hand. It is not secondary to inflation of the mean IRI of the non-preferred hand by the sporadic occurrence of long IRIs.

Journal Article↗
PubMed1988

Vascular complications associated with spontaneous aortic dissection.

Three hundred twenty-five cases of spontaneous aortic dissection seen at two institutions between 1965 and 1986 were reviewed to assess the incidence, morbid sequelae, and specific management of aortic branch compromise. Noncardiac vascular complications occurred in 33% of the study group, and in these patients the overall mortality rate (51%) was significantly (p less than 0.001) higher than in patients without (29%) such complications. Although aortic rupture was the strongest correlate of mortality (90%), death specifically related to vascular occlusion was common when such occlusion occurred in the carotid, mesenteric, and renal circulation. There was a strong correlation between stroke and carotid occlusion (22/26 cases), yet specific carotid revascularization was only used during the chronic phase of the disease. Similarly, peripheral operation was ineffective in reducing the mortality rate in the setting of mesenteric (87%) and renal (50%) ischemia. Fifteen patients required either fenestration or graft replacement of the abdominal aorta for acute obstruction, rupture, or chronic aneurysm development. Thirty-eight patients (12%) demonstrated some degree of lower extremity ischemia, and one third of these required a direct approach on the abdominal aorta or iliofemoral segments to restore circulation. Selected patients with acute aortic dissection may require peripheral vascular operation in accordance with a treatment strategy that directs initial attention to the immediate life-threatening complications.

Aged↗
PubMed1987

DNA hybridization for diagnosis of enteric adenovirus infection from directly spotted human fecal specimens.

By using a genomic probe, DNA hybridization for adenovirus type 41 (Ad41) showed equivalent sensitivity with a direct spot method from clinical specimens compared with a more laborious DNA phenol extraction procedure. By using this direct spot preparation method, fecal specimens of 67 patients were examined under code for blind testing for the presence of adenovirus by DNA hybridization by using two Ad41 probes (genomic and cloned BglII-D) and an adenovirus type 2 genomic probe. Identical results were obtained with both of the Ad41 probes. Of the fecal specimens from 42 children with adenovirus gastroenteritis studied prospectively (16 of whom had enteric adenoviruses), 13 specimens (81%) were detected by DNA hybridization with a cloned Ad41 BglII-D probe. There were 14 fecal specimens that were positive by electron microscopy (EM) and culture for nonenteric adenovirus, and 2 specimens were positive by DNA hybridization (87% specificity); these 2 specimens may have been from a mixed enteric adenovirus and nonenteric adenovirus infection. None of 26 specimens from age-matched healthy control patients was positive for adenovirus by EM or DNA hybridization. Our data indicated that DNA hybridization gives highly reproducible results. The direct spot technique is the method of choice for specimen preparation in the diagnostic laboratory, since it requires only the simplest manipulations in specimen preparation. By using DNA hybridization with the BglII D fragment of a cloned enteric Ad41, both adenovirus type 40 and Ad41 were detected directly from fecal specimens, but it was less sensitive than EM following direct ultracentrifugation of specimens. The Bg1II-D Ad41 DNA probe was highly specific for enteric adenoviruses, and DNA hybridization with this probe could be a useful diagnostic test for these fastidious adenoviruses.

Adenoviridae Infections↗
PubMed1981

Catheter-induced pulmonary artery perforation. Mechanisms, management, and modifications.

Six cases of pulmonary artery perforation associated with the use of Swan-Ganz catheters are reviewed. Risk factors included pulmonary hypertension, anticoagulation, and hypothermia. The mechanisms leading to perforation were clarified by the use of postmortem studies employing isolated whole lung preparations. These studies revealed that perforation results from (1) tip perforation of vasculature, (2) eccentric balloon configuration propelling the balloon through the vessel wall, and (3) balloon inflation disrupting the pulmonary artery (mean intraballoon pressure 250 mm Hg). Early clinical symptoms include hemoptysis of bright red blood and/or hypotension. Immediate evaluation may necessitate examination with a fiberoptic bronchoscope and "wedge" angiogram. If massive hemoptysis occurs, isolation of the unaffected lung by endobronchial intubation is mandatory. Pneumonectomy or lobectomy may be required. Revised guidelines for catheter insertion and pulmonary capillary wedge pressure (PCWP) measurements are presented. Finally, consideration is given to redesigning the pulmonary artery flow-guided catheter, particularly for use in patients undergoing cardiac operations with systemic anticoagulation. Modifications should be directed at (1) softer catheter tip with temperature-insensitive body, (2) low-pressure balloon, and (3) balloon pressure relief valve.

Aged↗
PubMed1981

Use of silicone rubber as a pericardial substitute to facilitate reoperation in cardiac surgery.

Reoperations following cardiac procedures have an increased risk because of the danger of damaging the heart, great vessels, or grafts because of adhesions to the sternum and anterior chest wall. We report our experience with the use of silicone rubber as a pericardial substitute in 102 patients--58 children undergoing palliative and corrective operations and 44 adults undergoing porcine valve insertion or coronary revascularization. The pericardial substitute was used only in cases in which reoperation was considered likely. There were no mediastinal infections. One adult had signs of cardiac constriction which improved markedly on administration of anti-inflammatory agents. Seven patients required reoperation for bleeding. Two patients who underwent Fontan procedures developed pericardial effusions necessitating a pericardial window. Reoperation was undertaken 1 to 12 months postoperatively in seven patients, all of whom were children. The silicon rubber greatly facilitated opening of the chest bone but did not affect the formation of adhesions within the pericardium. Postmortem examinations have been obtained in two cases 5 and 9 months postoperatively, and showed a thin layer of dense fibrous tissue adjacent to the silicone rubber. We conclude that silicone rubber may be used as a pericardial substitute and that it facilitates reoperation following cardiac operations. Particular caution should be used in patients undergoing Fontan procedures, as there appears to be a tendency for pericardial effusions and tamponade to develop.

Adult↗
PubMed1978

Radionuclide assessment of ventricular performance during propranolol withdrawal prior to aortocoronary bypass surgery.

The effects of oral propranolol upon left ventricular performance were assessed in 18 patients with angiographically documented coronary artery disease in whom propranolol was tapered prior to elective aortocoronary bypass surgery. Left ventricular ejection fraction, ejection rate, and regional wall motion were obtained on three occasions with first-pass radionuclide angiocardiographic techniques. Patients were studied at peak propranolol dose ( +/- SEM) 224 +/- 29 mg./day; serum propranolol level, 85 +/- 22 ng./ml.), intermediate dose (99 +/- 9 mg./day; serum propranolol, 30 +/- 6 ng./ml.), and 24 hours following discontinuation of propranolol therapy. Heart rate increased significantly (62 +/- 2.3 vs 67 +/- 3.0 vs 73 +/- 2.3 beats/minute, p less than 0.001) during propranolol withdrawal, while systolic blood pressure did not change significantly (114.7 +/- 4.3 vs 110.3 +/-3.0 vs 113 +/- 3.0 mm. Hg, p greater than 0.05). There was no significant change in ejection fraction (59.1 +/- 2.4 vs 60.4 +/- 2.0 vs 59.2 +/- 2.5 per cent) or ejection rate 2.80 +/- 0.18 vs 2.87 +/- 0.18 vs 2.92 +/- 0.20 sec.-1) as propranolol was tapered (p greater than 0.05). No patient demonstrated a change in regional wall motion in response to propranolol withdrawal. The results of this study suggest that oral propranolol in commonly used clinical dosages does not significantly affect radionuclide measures of left ventricular performance in the basal state.

Administration, Oral↗