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Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 595 records · Page 33Linked to original sources
PubMed1989

Dental caries at five and twelve years in a South African Indian community: a longitudinal study.

In 1979, 515 of 767 available Indian children born in Lenasia in 1974 were examined and their dental caries status was described. In 1986, 515 of the original 715 were re-examined in order to determine the pattern of dental caries in the primary and permanent dentitions of the same individuals. In contrast to studies in the literature in which treatment records have been used, both investigations were formal epidemiological field studies using calibrated examiners and WHO (1971) caries diagnostic criteria. A firm association was found between caries in the primary and permanent dentitions (r = 0.34).

Child↗
PubMed1989

Therapeutic activity of meropenem in experimental infections.

Meropenem and comparative antibiotics were evaluated in five models of infection. All antibiotics were administered parenterally; imipenem was used in combination with cilastatin but meropenem and other agents were given alone. Generalized infections in mice caused by Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Serratia marcescens, Proteus mirabilis or Pseudomonas aeruginosa all responded to low doses of meropenem or imipenem. Immunocompromised mice infected with Ps. aeruginosa responded to slightly higher doses of meropenem or gentamicin but required four to seven times the dose of other agents. Those given a greater challenge of Ps. aeruginosa were treated most successfully by meropenem. Treatment with meropenem, imipenem or ceftazidime caused significant reductions of E. coli in the urinary bladder and kidneys of mice challenged per urethram. Infection with Ps. (Xanthomonas) maltophilia localized to the subcutaneous neck tissue of guinea pigs was also treated successfully. Lung infections caused by Ps. aeruginosa in guinea pigs were treated effectively by meropenem, imipenem, and ceftazidime at the dose of 10 mg/kg but only meropenem eradicated bacteria from all the tissues examined. These results demonstrate that meropenem has excellent antibacterial activity in vivo in both normal and immunocompromised animals and in some models of infection is superior to imipenem.

Animals↗
PubMed1989

Changes in head posture and nasopharyngeal airway following surgical correction of mandibular prognathism.

It was the aim of the present study to cast light on the role of the mandible in relation to head posture and airway space by evaluating patients before and after surgical correction of mandibular prognathism. The material comprised standardized profile cephalograms of 52 patients with mandibular prognathism. All patients had received orthodontic adjustments prior to mandibular osteotomy. Mean age of the patients was 24.3 years, and 12 males and 40 females participated in the study. The first profile radiograph of each patient was obtained the day before surgery in the natural head (mirror) position. All patients underwent mandibular surgery with a bilateral vertical ramus osteotomy. Approximately one year after surgery, the cephalometric investigation was repeated. Head posture was evaluated by the craniocervical angulation (NSL/CVT and NSL/OPT) and airway space as nasopharyngeal airway size (ad1 and ad2). Changes in posture and airway (ex.2-ex.1) were evaluated by paired t-tests. The results showed a mean increase in head posture of 2.7 degrees (p less than 0.001) and a mean reduction in airway space of 2.3 mm (p less than 0.001).

Adolescent↗
PubMed1989

Cognitive and social correlates of DSM-III disorders in preadolescent children.

The relationships between some cognitive and social measures and the major syndromes found in a large preadolescent sample of children from the general population are described. The measures discriminated between disorder-no disorder for most variables examined and between the broad groups of externalizing and internalizing disorders, but not between individual diagnostic categories. An important exception was that ADDH and conduct disorder occurring as single disorders could be distinguished, but the frequent comorbidity of these and other disorders complicated many between-group comparisons.

Child↗
PubMed1989

Effect of limb tourniquet on cerebral perfusion pressure in a head-injured patient.

Thirty percent of patients with severe head injury also have significant extracranial injuries. Treatment for these injuries should not be allowed to jeopardise the brain which is more susceptible to damage in these circumstances. A case is presented in which significant decrease in cerebral perfusion pressure occurred consequent upon use of a lower limb tourniquet.

Adolescent↗
PubMed1989

Platelet aggregation induced by type IIb platelet von Willebrand factor.

Platelet lysates from five patients with a form of type IIb von Willebrand's disease (vWd), associated with spontaneous platelet aggregation and thrombocytopenia, induced platelet aggregation of normal and other vWd's platelet-rich plasma (PRP). Platelet lysate from normals, type I or type IIa vWd did not cause platelet aggregation of normal PRP. When polyclonal monospecific antibodies directed against plasma von Willebrand factor (vWf) were incubated with the type IIb platelet lysate, they inhibited the platelet aggregation. Monoclonal antibodies directed against the glycoprotein (GP) Ib binding domain of plasma vWf incubated with the type IIb platelet lysate did not inhibit the platelet aggregation. Normal platelets suspended in afibrinogenaemic plasma did not aggregate when type IIb vWd platelet lysate was added. Normal platelets incubated with monoclonal antibodies directed against the fibrinogen and vWf binding site(s) on the GPIIb/IIIa were not aggregated by the type IIb platelet lysate. Bernard-Soulier PRP aggregated when type IIb vWd platelet lysate was added, while Glanzmann's thrombasthenic platelets did not. Peptides containing the RGDS sequence or the sequence of the carboxy terminal 15 amino acids of the gamma chain of fibrinogen inhibited the type IIb vWd platelet lysate-induced platelet aggregation. These data suggest that type IIb platelet vWf can cause platelet aggregation of PRP without the addition of any agonist. This interaction is different from that observed with the plasma vWf from these patients.

Antibodies, Monoclonal↗
PubMed1989

Poor compliance early in filling in the neuropathic bladder.

A total of 30 patients with known neuropathy, mostly spina bifida, developed poor bladder compliance early in filling demonstrated urodynamically; 20 had bilateral hydronephrosis at the time of presentation and 5 also had severely impaired renal function. After appropriate treatment all of those with normal upper tracts or with bilateral hydronephrosis but normal renal function stabilised or improved. However, all 5 with severely impaired renal function progressed to end-stage renal failure. Poor compliance early in filling is an absolute indication for surgical intervention.

Adolescent↗
PubMed1989

Panoramic screening for dental anomalies assessed by professionals with identical and different backgrounds.

The aim of the present study was to evaluate how dental professionals with identical and different backgrounds assess dental anomalies viewed on panoramic radiographs. 101 panoramic radiographs performed of 9-to-10-yr-old children were examined independently by three orthodontists and two radiologists. All observers agreed on the recording of number and identification of congenitally missing permanent teeth. The observers' assessments of malpositioned teeth, teeth in infraocclusion, and primary teeth with atypical/non root resorption varied, however, to a great extent. Two of the orthodontists seemed to report only major deviations from normality (in 38 and 51 of the children respectively) while one reported several more findings (in 85 children). The radiologists reported abnormal findings in 80 and 88 children respectively. In only three children were no dental anomalies reported by any observer. The inconsistent reporting of the majority of dental anomalies (except for agenesis) in children, even among members of subgroups with a similar educational background (e.g. orthodontists), substantiates the need for an evaluation of the expedience of panoramic screening.

Anodontia↗
PubMed1989

Hypopharyngeal reconstruction: a comparison of two alternatives.

Gastric pull-up or free jejunal interposition was used for reconstruction after total laryngopharyngectomy in 31 patients. Complications and functional outcomes of the two methods are compared. Primary swallowing was achieved in 86% of patients after gastric pull-up and in 82% of patients after jejunal interposition. Patients who underwent jejunal interposition were able to swallow sooner and had a shorter hospital stay than patients who underwent gastric pull-up. Esophageal tumor recurrence after jejunal interposition was not observed. Hepatic failure occurred in two gastric pull-up patients, leading to perioperative death in one. Flap necrosis occurred in two jejunal interposition patients and one gastric pull-up patient. Two additional fistulas occurred in jejunal interposition patients as a result of microvascular complications. Stricture developed in four jejunal interposition patients, requiring revision surgery in two. Minor complications were more common in the gastric pull-up group. Long-term speech and swallowing function are compared. Our current choice of jejunal interposition or gastric pull-up for reconstruction after total laryngopharyngectomy primarily depends on the location of the tumor.

Aged↗
PubMed1989

Cow's milk-induced pulmonary hemosiderosis.

Cow's milk protein-induced pulmonary disease is a serious condition which, if recognized, can be treated effectively by avoidance of milk protein; untreated it may lead to early death. It should be considered in any child who suffers recurrent episodes of pneumonia and anemia.

Child, Preschool↗
PubMed1989

Improving interviewing of and compliance by the adolescent.

Effective interviewing of adolescents rests upon a knowledge of developmental processes and biopsychosocial approach to care. The effective interviewer, by building a satisfactory relationship with the adolescent, is much more likely to obtain compliance with therapy. This article contains tips on how to improve interviewing of and compliance by your adolescent patients.

Adolescent↗
PubMed1988

Muscarinic depression of long-term potentiation in CA3 hippocampal neurons.

Behavioral studies have suggested that muscarinic cholinergic systems have an important role in learning and memory. A muscarinic cholinergic agonist is now shown to affect synaptic plasticity in the CA3 region of the hippocampal slice. Long-term potentiation (LTP) of the mossy fiber-CA3 synapse was blocked by muscarine. Low concentrations of muscarine (1 micromolar) had little effect on low-frequency (0.2 hertz) synaptic stimulation but did significantly reduce the magnitude and probability of induction of LTP. Experiments under voltage clamp showed that muscarine blocked the increase in excitatory synaptic conductance normally associated with LTP at this synapse. These results suggest a possible role for cholinergic systems in synaptic plasticity.

Animals↗
PubMed1988

Autoimmunity in IgA nephropathy.

IgG autoantibodies with specificity for glomerular antigenic determinants have been detected in the sera of 23 of 75 patients with IgA nephropathy. The antigen or antigens are distinct from the Goodpasture antigen and have at least three components that bind IgG. The components are of molecular weight 185, 160, and 30-40 kD by high performance liquid chromatography, and, deaggregated, 69 to 30 kD by immunoblotting, with variation in affinity between patients. The autoantibody was detected more frequently in patients with IgG glomerular deposits, was present in sera intermittently, and was associated with clinical evidence of nephritis. IgG autoantibody secretion may be a component of the polyclonal B cell activation that accompanies infection-induced nephritis in IgA nephropathy.

Antibody Affinity↗