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Biomedical subjects

L Voss

Publications and source records attributed to L Voss.

33 records · Page 2Linked to original sources
PubMed1994

Reaction of the pterygomaxillary fissure and the condylar cartilage to intermaxillary Class III magnetic mechanics.

The skeletal reaction to Class III intermaxillary magnetic mechanics was previously found to affect two target areas, the pterygomaxillary fissure (PMF) and the condylar cartilage. The objectives of this study were to analyze, radiographically and histologically, the response of these tissues to Class III intermaxillary functional orthopedic magnetic appliance (FOMA III), and to postulate possible models of their dichotomous biomechanism. Nine Macaca fascicularis monkeys received periodic administration of vital bone procion dye and were treated for 4 months with FOMA III (6 subjects) and sham appliance (3 subjects). The PMF (the target area of the midfacial complex) demonstrated a decreased skeletal reaction in inferosuperior and lateromedial directions. Cephalometrically, the lowermost PMF point was displaced inferiorly 1.98 +/- 1.74 mm and 0.42 +/- 0.38 mm and anteriorly 1.42 +/- 0.96 mm and 0.58 +/- 0.38 mm in the treated and control groups, respectively. The displacement of the uppermost PMF point, compared with the lowermost point, was three to five times lower. Histologically, two modes of response were found; first, a sutural response (disarticulation and osteogenesis) of the palatomaxillary and pterygopalatine sutures, which was distinctive of the lateral PMF aspect, and second, a dentosutural response, which was characteristic of the medial PMF aspect (bony microfractures between the third molar germ and the maxillary tuberosity in conjunction with mild sutural response). In the mandible, a discrepancy was found between the histologic and the cephalometric findings. Radiographically, mandibular length was unaffected after 4 months of treatment, and the distance condylion-pogonion was equally increased in the treated (0.75 +/- 0.78 mm) and the control animals (0.77 +/- 0.32 mm). Histologically, however, the condylar cartilage demonstrated increased osteoclastic activity at the zone of endochondral ossification and a decreased apposition rate at the adjacent bony trabeculae. Conceivably, the two target areas (PMF sutures versus condylar cartilage) demonstrate two diverse time-related responses that are either unrelated or interrelated to each other. An unrelated tissue response suggests that tissue stimulation (sutural) is always superior to tissue suppression (condylar). Another possible unrelated tissue reaction implies diverse response velocity (high sutural, low condylar). An interrelated mechanism suggests that an applied force will dissipate initially at the less resistant target area (sutures), and will subsequently affect the more resistant target area (condyle) once the sutural resistance exceeds a certain threshold. The fact that no pathologic change was found in the condylar cartilage encourages a long-term use of the FOMA III appliance, initiating treatment at an early skeletal age.

Animals↗
PubMed1994

Invasive pneumococcal disease in a pediatric population, Auckland, New Zealand.

Streptococcus pneumoniae is one of the major invasive pathogens in childhood. The increasing worldwide prevalence of penicillin-resistant strains makes management of invasive infections difficult and underscores the need for effective vaccines. Currently available vaccines are of limited value in the pediatric age group. Trials are taking place to evaluate conjugated pneumococcal vaccines and in view of this it is important to establish local epidemiology of pneumococcal disease. The aims of this population-based study were to review all of the cases of invasive pneumococcal disease occurring during a 9-year period (1984 to 1992) in Auckland, New Zealand. Through the use of laboratory records and hospital discharge codes, 413 isolates from 407 patients were found. Age-specific incidence for all invasive disease was 22.0/100,000 for children less than 15 years old but 56.0/100,000 for children less than 5 years old (chi 2 Yates corrected 18.20; P = 0.001). Two-thirds were less than 2 years old. The rates were higher in Maori and Pacific Island children than in Caucasian children. A total of 70 isolates from 68 patients with meningitis occurred. The majority were less than 5 years old (incidence of meningitis was 10.0/100,000) and 84% were less than 2 years old. The overall mortality from meningitis was 4.3%. Of the 129 isolates serogrouped or serotyped, 14, 6 and 19 accounted for 23%, 16% and 16%, respectively, of cases. Although 98% of serotypes identified would be covered by the currently available 23-valent vaccine, two-thirds of the children affected by these isolates would be unprotected because of poor immunogenicity of polysaccharide vaccines in children less than 2 years old.

Adolescent↗
PubMed1994

Epidemiology, management, and prevention of meningococcal infections.

Neisseria meningitidis is the cause of significant morbidity and mortality worldwide, both in epidemic and endemic disease form. The use of serotyping, subtyping, and multilocus electrophoresis has had a significant impact on determination of the epidemiology of meningococcal disease. Recent advances in understanding the pathogenesis of meningococcal disease, include information on the role of cytokines and other inflammatory mediators, which may contribute to establishment of additional diagnostic and treatment options. Early treatment is required to improve outcome along with the use of prophylaxis to prevent secondary disease. Vaccines against groups A, C, Y, and W135, are available but have limitations, with regard to efficacy and duration of protection. Over the past decade there has been rapid progress in the development of a vaccine against group B disease, with protective trials underway in several countries. However, varying results have been found and these vaccines have not reached a stage of providing universal protection against group B meningococcal disease.

Adolescent↗
PubMed1993

Disturbance of colour perception in Parkinson's disease.

A computer-aided method for the determination of colour fusion time (CFT) was developed. CFT indicates the acuity of the perception of monochromatic contours. CFT was determined in 36 patients with Parkinson's disease (PD) and compared with a group of 36 age- and sex-matched controls. Patients with PD generally had a shortened fusion time, especially for dark-green, light-blue and dark-red stimuli. The results give evidence to the hypothesis of a colour perception disorder in PD. The physiological and pathoanatomical basis of this phenomenon is unknown, but a functional deficit of cortical neurons may be a probable cause.

Adult↗
PubMed1992

Autoantibodies to endogenous growth hormone in short children (the Wessex Growth Study).

Small stature is associated with low growth hormone secretion, but in most cases the reason is unknown. The commonest cause of hormone insufficiency is autoimmunity, and autoantibodies to hormones are often found where there is autoimmune disease of the corresponding gland. Displaceable growth hormone binding by the sera of 125 short (< 3rd centile) but otherwise normal school entrants was significantly higher (P < 0.05) than by the sera of 100 age-matched children of normal height (10th-90th centile), and binding in 21 (17%) of the small children exceeded the upper limit of 95% of the normal population. Furthermore, urinary growth hormone excretion was significantly lower in the small children (total overnight output 0.6-1.7 ng) compared with controls (1.5-3.7 ng) (P < 0.05) even when corrected for body surface area. Thus, growth hormone binding and growth hormone excretion discriminated between two groups of children selected only on the basis of height. The assay used for growth hormone binding was specific for IgG, suggesting that the binding factor was antibody. Autoimmunity merits further investigation as a basis for poor growth.

Autoantibodies↗
PubMed1992

Successful intervention in a group A meningococcal outbreak in Auckland, New Zealand.

During two consecutive winter seasons (1985 and 1986) Auckland, New Zealand, experienced epidemic rates of Group A meningococcal disease, a pattern not previously recognized in New Zealand. The overall rate was 8.3/100,000/year. The highest annual rate (64.7) occurred in children 0 to 23 months of age. A city-wide vaccine campaign commencing in May, 1987, was conducted over 6 weeks among children 3 months to 13 years of age with special emphasis on reaching populations at highest risk (Maori and Pacific Island Polynesian children in certain geographic regions of Auckland). Children from 2 to 13 years of age received a single dose of monovalent Group A meningococcal vaccine. Children ages 3 to 23 months received two doses at least 1 month apart. Overall approximately 130,000 doses were delivered; coverage was approximately 90% in the single dose target group. Among the younger children approximately 89% received the primary dose. Only approximately 26% received the recommended "booster" dose. After 2 1/2 years of active surveillance (1987 to 1989) there were no cases of invasive Group A meningococcal disease in children appropriately vaccinated for age. In contrast to this 100% efficacy the efficacy of a single dose of monovalent Group A meningococcal vaccine to prevent illness in the youngest children during the 1987 epidemic period was 52% (95% confidence interval (-330%, 95%)) falling to 16% (95% confidence interval, (-538%, 90%)) after 1 year. Four cases that occurred in infants 3 to 7 weeks before the scheduled "booster" campaign supports limited true efficacy. However, the prescribed 1 to 3-month interval between the two doses in infants may be too long.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Vaccines↗
PubMed1989

The clinical features of paediatric meningococcal disease Auckland, 1985-87.

An epidemic of group A meningococcal disease began in Auckland in May 1985. There were 122 paediatric cases of meningococcal disease in the next 25 months including 98 cases due to group A. The commonest clinical symptoms were vomiting, headache and photophobia, while frequent signs included fever, seizures, petechial rash and meningism or a bulging fontanelle. Complications were uncommon and included sterile arthritis and prolonged fever. The majority had disease confirmed by positive blood or cerebrospinal fluid culture. Significantly fewer positive cultures were seen in those treated with antibiotics prior to admission. The overall mortality was 7%. If the acute illness was survived, the only detected long term sequela was sensorineural hearing loss seen in 6%. A vaccine programme has been undertaken to control this epidemic.

Adolescent↗
PubMed1989

Haemophilus influenzae type b disease in Auckland children 1981-87.

Haemophilus influenzae type b invasive disease was reviewed in the Auckland paediatric population. A total of 205 episodes were confirmed by sterile cavity culture in 203 patients under 15 years of age over a seven year period. The incidence of invasive disease was 14/100,000/year in those under 15 years and 41/100,000/year in under 5 year olds. The age range was from 1 month to 11 years, with 91% under 5 years and 64% under 2 years. Most cases were due to meningitis (63%). Other diseases included epiglottitis, pneumonia, cellulitis, arthritis, and occult bacteraemia. There was only one fatality. Beta lactamase production was found in 9% of meningeal isolates. Recently a new conjugated haemophilus vaccine has been licensed in the United States for use in children 18 months and older. Consideration should be given to introducing this vaccine in New Zealand.

Age Factors↗
PubMed1989

An outbreak of meningococcal disease in Auckland, New Zealand.

A large epidemic of disease caused by Group A sulfonamide-resistant Neisseria meningitidis has been occurring in Auckland, New Zealand, from June, 1985, and peaking in October, 1985 (spring), and June, 1986 (winter). By the end of 1986 an overall attack rate of 8.3 cases/100,000 total population per year had been calculated. The attack rate in children younger than 15 years was 30.4/100,000/year and the highest rate occurred in children younger than 5 years: all Auckland 68.8/100,000/year; South and Central Auckland 98.7/100,000/year. Seventy-nine percent of cases younger than 15 years of age occurred in 30% of the childhood population. The overall case-fatality ratio was 7% with the highest rate (22%) occurring in male children age 1 to 2 years. An outbreak in an industrialized country of an infectious disease usually seen in developing countries calls for investigation of living conditions and other sociodemographic factors in the population affected. Specific action in the form of a vaccination program particularly targeted to those at risk was planned and implemented before the winter of 1987.

Age Factors↗
PubMed1989

The Wessex Growth Study: first report.

The Wessex Growth Study is a community-based longitudinal survey of short children recruited from two Health Districts in Wessex during 1985-86 (cohort I) and 1986-87 (cohort II). Screening of new school entrants during 1985-86 identified only 1.3% who were at or below the 3rd centile for height as defined by Tanner and Whitehouse, suggesting a strong secular trend and an urgent need for updated height charts. After exclusion of the small number of children with underlying organic pathology and those from ethnic minorities, there were 84 children in cohort I on whom this report is based. These apparently normal, short children were sex- and age-matched with normal controls (10th-90th centile) from the same school class. Forty-two per cent of cohort I had a delayed bone age, and 34% lay above the 3rd centile after correction for parental height. Forty-four per cent were of low birth weight. The correlation between two successive height velocities measured at 6 and 12 months was only -0.14 for cohort I and -0.15 for their controls. Twelve-month mean height velocity SD scores (SDS) were -0.45 and +0.25, respectively, corresponding to the 33rd and 60th centiles, and rather higher than the 25th and 50th centiles expected in view of the heights of these children. Thirty-eight per cent of cohort I had a 12-month height velocity below the 25th centile, and in 16% height velocity was below the 10th centile. As a group, the children in cohort I grew more slowly than their controls, but the height velocity in 88% of cases lay within the control range.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Determination by Skeleton↗
PubMed1986

[Technic of exact lung puncture].

The accuracy can be improved, and the risk of complications can be reduced in the case of cytodiagnostic lung puncture, if one optimises the method whereby the puncture needle is inserted into the lesion. The author describes such a procedure incorporating the use of technical aids for marking the exact puncture point of the cannula. At the same time the procedure results in a reduction of radiation exposure of both doctor and patient.

Biopsy, Needle↗