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Biomedical subjects

B Wood

Publications and source records attributed to B Wood.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of secondary structures in water of chondroitin-4-sulfate and dermatan sulfate: implications in the formation of tertiary structures.

Chondroitin-4-sulfate (CS4) and dermatan sulfate (DS) were examined in D2O solution, with or without NaCl, by NMR at 300 MHz, to investigate the physicochemical consequences of epimerization of glucuronate (GlcUA in CS4) to iduronate (IdoUA in DS). Nuclear Overhauser effects (NOEs) and spin-lattice relaxation times following selective and nonselective inversion were measured at up to 70 degrees C. (1) NOEs confirmed 4C1 conformations of sugar rings in N-acetylgalactosamine and GlcUA, and 1C4 or 2S0 in IdoUA. Conflict between NMR data and periodate oxidation kinetics over IdoUA conformations is resolvable by postulating conversion of monodentate periodate-1C4 complexes to conformations in which periodate oxidation can procede. (2) Pairs of glycosidic protons in CS4 and DS showed strong NOEs, implying that stretches of 2-fold helix were present, with carboxylate and acetamido groups close to each other on the same side of tapelike molecules, extending previous work in dimethyl sulfoxide solution. CS4 and DS have large hydrophobic patches in this configuration, similar to those in keratan sulfate and hyaluronan. (3) Selective and nonselective inversion-recoveries implied similar segmental and backbone mobilities and hence flexibilities in CS4 and DS. This is discussed in terms of intrinsic flexibility of glycosidic conformations, modified by hydrogen-bonded arrays. (4) We postulate that hydrophobic and hydrogen bonding drives DS self-aggregation. Stronger self-aggregation of DS compared with CS4 is attributed to increased intermolecular hydrogen-bonding in DS, secondary to decreased intramolecular hydrogen-binding. This is partly because the axial OH groups in 1C4 IdoUA cannot hydrogen-bond to neighboring sugars as can the equatorial OH groups in GlcUA of CS4.

Animals↗
PubMed1995

Presentation of acute Wernicke's encephalopathy and treatment with thiamine.

Thirty two cases of acute Wernicke's encephalopathy were observed in a period of 33 months, and prior to the mandatory thiamine enrichment of Australian bread-making flour in 1991. These cases were carefully assessed by multiple tests at specified intervals prior to, and following thiamine administration until discharge from hospital. Structured scoring of neurological signs and symptoms, CT scans, psychometry, nutritional measurements, and liver biopsies were performed. There was variation in the presentation and severity of clinical signs and symptoms and in response to treatment. All patients had alcohol-related liver disease, and the results indicated that fatty liver was important in presentation and in response to treatment with thiamine. Other forms of alcohol related brain damage were present in these patients, most of whom were in the 4th or 5th decade of life and had been drinking beer to excess for more than 20 years.

Alcoholic Intoxication↗
PubMed1995

Symptomatic fluid retention in patients on continuous peritoneal dialysis.

The clinical features, pathogenesis, management, prognosis, and predictors of symptomatic fluid gain (SFR) were analyzed for 71 episodes occurring in 66 patients on continuous peritoneal dialysis, 94.4% on continuous ambulatory peritoneal dialysis (CAPD) and 5.6% on continuous cycling peritoneal dialysis. Compared with a control group of 149 CAPD patients, the SFR group had a higher percentage of diabetics (64 versus 46%) and a higher frequency of noncompliance with fluid restriction (76 versus 22%), salt restriction (74 versus 23%), and performance of dialysis (30 versus 7%) (all at P < or = 0.015). Peripheral edema (100%), pulmonary congestion (80%), pleural effusions (76%), and systolic (83%) and diastolic (66%) hypertension were the most common manifestations of SFR. The annual hospitalization rate for SFR was 4.1 +/- 5.8 days per patient. SFR resulted in the discontinuation of CAPD in 10 patients and death in 1 patient. Serum sodium concentration was not different between dry and maximal weight in the SFR group. Thirty-eight (58%) of SFR and 61 (41%) of control patients were evaluated by peritoneal equilibration tests (PET). SFR patients had lower PET drain volume (2.08 +/- 0.47 versus 2.54 +/- 0.23 L) and a higher frequency of high peritoneal solute transport (32.2 versus 2.4%). In this group, logistic regression identified dietary noncompliance, low PET drain volume, and young age as independent predictors of SFR. Response to management and preventive measures was inconsistent. The best results were obtained by the use of short dwell exchanges with hypertonic dialysate in compliant patients with high peritoneal solute transport. SFR has serious consequences in CAPD. (ABSTRACT TRUNCATED AT 250 WORDS)

Diet, Sodium-Restricted↗
PubMed1995

A new device for pleural drainage in newborn infants.

OBJECTIVE: We tested a chest tube device and insertion technique designed to reduce complications and expedite effective thoracostomy tube placement. METHODOLOGY: This is a case series study. We placed chest tubes using this device in 25 infants ranging in weight from 425 to 3500 g. This investigation was performed in a regional referral center neonatal intensive care unit. RESULTS: Using this device, chest tube insertion was safe and effective. No complications were identified. CONCLUSION: We believe percutaneous placement of small-bore pigtail catheters using this technique represents a useful alternative to the standard approach of thoracostomy tube placement in small infants. SYNOPSIS: To reduce complications during thoracostomy tube placement and to expedite tube insertion, we modified a chest tube device for use in premature infants. This technique and device facilitates quick and accurate placement. We placed chest tubes using this device in 25 infants ranging from 425 to 3500 g. Using this device, chest tube insertion is quick, easy, and safe. No complications were identified. We believe percutaneous placement of small-bore pigtail catheters using this technique represents a useful alternative to the standard approaches of thoracostomy tube placement in small infants.

Birth Weight↗
PubMed1994

Implications of early hominid labyrinthine morphology for evolution of human bipedal locomotion.

The upright posture and obligatory bipedalism of modern humans are unique among living primates. The evolutionary history of this behaviour has traditionally been pursued by functional analysis of the postcranial skeleton and the preserved footprint trails of fossil hominids. Here we report a systematic attempt to reconstruct the locomotor behaviour of early hominids by looking at a major component of the mechanism for the unconscious perception of movement, namely by examining the vestibular system of living primates and early hominids. High-resolution computed tomography was used to generate cross-sectional images of the bony labyrinth. Among the fossil hominids the earliest species to demonstrate the modern human morphology is Homo erectus. In contrast, the semicircular canal dimensions in crania from southern Africa attributed to Australopithecus and Paranthropus resemble those of the extant great apes. Among early Homo specimens, the canal dimensions of Stw 53 are unlike those seen in any of the hominids or great apes, whereas those of SK 847 are modern-human-like.

Animals↗
PubMed1994

Anophthalmia, cleft lip/palate, facial anomalies, and CNS anomalies and hypothalamic disorder in a newborn: a midline developmental field defect.

We describe an infant with a unique pattern of midline defects, including anophthalmia, cleft lip and palate, macrocephaly, cutis aplasia, and micrognathia. CNS anomalies including massive hydrocephalus with destruction of most recognizable structures were observed. The infant also developed panhypopituitarism, diabetes insipidus, and a seizure disorder. We postulate that this patient could represent a more complex form of the Delleman syndrome or a new morphogenetic syndrome secondary to ventral induction with extension to the developmental fields of the first and second branchial arches.

Abnormalities, Multiple↗
PubMed1994

Paranthropus boisei: an example of evolutionary stasis?

Of the presently recognised early hominid species, Paranthropus boisei is one of the better known from the fossil record and arguably the most distinctive; the latter interpretation rests on the numbers of apparently derived characters it incorporates. The species as traditionally diagnosed is distributed across approximately one million years and is presently confined to samples from East African sites. The hypodigm has been examined for evidence of intraspecific phyletic evolution, with particular emphasis on the areas best represented in the fossil record, namely the teeth and mandible. The results of this examination of 55 mandibular and dental variables which uses the gamma test statistic for the detection of trend, and nonparametric spline regression (Loess regression) for investigating pattern and rate of temporal change, show that within Paranthropus boisei sensu stricto most evidence of temporally related morphological trends relates to the morphology of the P4 crown. There is little or no evidence of any tendency to increase in overall size through time. Fossils from the Omo Shungura Formation and West Turkana which have been recovered from a time period earlier than the P. boisei sensu stricto hypodigm resemble the latter taxon in some features, but differ from it in aspects of cranial morphology. There is insufficient fossil evidence of the earlier taxon to tell whether it changes through time, but when trends of 47 mandibular and dental variables are assessed across the combined East African "robust" australopithecine sample, there is evidence for a relatively abrupt change around 2.2-2.3 Myr in approximately 25% of the dental and mandibular remains. Some of these changes correspond with the temporal trends within P. boisei sensu stricto, but others, such as mandible height, do not. If the earlier material is ancestral to P. boisei sensu stricto, evidence from the teeth and jaws is consistent with a punctuated origin for the latter taxon.

Africa, Eastern↗
PubMed1994

Acquired immunodeficiency syndrome-related lymphoma of the lung presenting as empyema thoracis.

B-cell lymphoma in patients infected with the human immunodeficiency virus is usually a disseminated process that occasionally involves the lungs. Surgical diagnosis is often necessary to distinguish this from other neoplasms or opportunistic infections of the lung. We report a case of pulmonary B-cell lymphoma in a patient infected with human immunodeficiency virus who presented with a left empyema thoracis and an associated left lower lobe abscess secondary to bronchial obstruction. Resection was performed and the patient subsequently recovered from the acute process and survived an additional 6 months. This report demonstrates that surgical intervention may be necessary for both the diagnosis of pulmonary lymphoma and the definitive management of infectious complications that may arise as a result of pulmonary neoplastic disease in patients with acquired immunodeficiency syndrome.

Adult↗
PubMed1994

A new laser-ultrasound transducer for medical applications.

A new type of probe is presented, which combines an ultrasound receiver constructed from piezoelectric polymer materials with a coaxial optical fibre for laser-induced ultrasound. The initial application of this probe, which may be further miniaturized, is in intra-arterial imaging and therapy. Overall diameters of the prototype probes presently range from 2.5 mm to 10.0 mm. Pulsed laser beams are introduced through the optical fibre to form a photoacoustic source within the material under investigation. Ultrasonic waves are induced in the material due to the photo-acoustic effect and received on return by a forward-looking piezoelectric polymer transducer. In principle, other high-power laser beams can also be introduced through the same optical fibre for therapeutic use. Initial development and characterization of this combined probe is reported in this paper, together with some results.

Acoustics↗
PubMed1994

Coalitions and family problem solving with preadolescents in referred, at-risk, and comparison families.

This study tested the hypothesis that the mother-father coalition, parent-child coalitions, and parental warmth expressed toward the child are associated with family problem solving in families with a preadolescent child referred for treatment of behavior problems (n = 30), families with a child at-risk for conduct disorder (n = 68), and a sample of comparison families (n = 90). Referred and at-risk families displayed less effective problem solving. A regression analysis, which controlled for gender of the child, family structure, family income, marital satisfaction, and severity of child problems, showed that strong parental coalitions were linked to low levels of family problem solving in at-risk and referred families. Parent-child coalitions had little apparent impact while parental warmth was highly correlated with better family problem solving. The results may be interpreted as evidence for a tendency for parents in at-risk and referred families to "scapegoat" a preadolescent during family problem-solving sessions. This may undermine progress on family problem solutions and may complicate family-based prevention and treatment programs that use family problem-solving sessions.

Adolescent↗
PubMed1994

Exercise blood pressure response and skeletal muscle vasodilator capacity in normotensives with positive and negative family history of hypertension.

OBJECTIVE: To study exercise blood pressure response in association with exercising muscle maximal vasodilatory capacity in normotensives with a positive and negative family history of hypertension. SUBJECTS: Twenty-eight normotensive healthy subjects were recruited. Of these, two females and 13 males had a positive, and three females and 10 males had a negative, family history of hypertension. METHODS: Both groups of subjects rode a bicycle ergometer while systolic blood pressure, diastolic blood pressure and heart rate were measured at 30%, 60% and peak oxygen uptake rate. The vasodilatory capacity was examined in the lower leg by measuring the minimal vascular resistance during peak reactive hyperemia after 10 min arterial occlusion. RESULTS: Age, body weight, resting blood pressure, peak oxygen uptake rate and casual lower leg vascular resistance were not significantly different between the two groups of subjects. Significantly higher exercise systolic blood pressure (9%) and diastolic blood pressure (9%) were seen in the subjects with positive family history of hypertension compared with the subjects with negative family history of hypertension. Exercise heart rate was significantly higher in the subjects with negative than in those with positive family history of hypertension. The vascular resistance at peak vasodilation was 22% higher in the subjects with positive than in the subjects with negative family history of hypertension. CONCLUSIONS: This study demonstrates that the dynamic exercise blood pressure is exaggerated and skeletal muscle vasodilatory capacity is limited in normotensives with genetic risk of hypertension. This suggests that the higher pressor response to physical stress that is found in normotensives with a family history of hypertension may be attributed to the resistance vessels in the exercising muscle.

Adult↗
PubMed1993

The interparental relationship and family problem solving with preadolescent males.

This study examines associations between the quality of the interparental relationship and how well 68 family triads (mother, father, preadolescent son) solved salient problems which arose at home. Four aspects of the interparental relationship (marital satisfaction, parental agreement, conflict during family problem solving, and parental coalitions) were included in a regression analysis which controlled for family structure and child externalizing. A longitudinal design assessed families when mean child age was 9.7 years and 2 years later. Parental agreement consistently facilitated family problem solving. However, strong parental coalitions inhibited family problem solving, which may be attributed to frustrated autonomy needs of preadolescent males in response to the parental coalition. Stepfamilies had less effective problem solving at Time 1. The results confirm the benefits of parental agreement to child outcomes via enhanced family problem solving but show a reverse effect when agreement occurs in the context of coalitions against a preadolescent son.

Child↗
PubMed1993

Sexual harassment of health care students by patients.

1. Forty percent of the 158 nursing and occupational therapy students surveyed reported being victims of sexual harassment. 2. When confronted with sexual advances or assaults, students used previously learned coping strategies. Thirty-nine percent ignored the behavior or joked about it. 3. A training program was designed and implemented to make students feel better able--and more empowered--to handle sexual harassment.

Adolescent↗