Benign paroxysmal vertigo in childhood: a long-term follow-up.

Benign paroxysmal vertigo in children is characterized by sudden attacks of vertigo lasting seconds or minutes. During the attack, the child has nystagmus and is unable to stand without support. Initially, the attacks are frequent, later slowly disappearing. Nineteen children who were diagnosed in 1975-1981 participated in a follow-up study. Sixteen of them were examined with audiometry and electronystagmography. Age at onset was from 5 months to 8 years, and the symptoms disappeared after 3 months to 8 years. The follow-up was performed 13 to 20 years after diagnosis. Twenty-one percent developed migraine which is somewhat more than in a normal population of this age. Thirty-nine percent had a family history of migraine which is a figure considerably lower than in a migraine population. None still had vertigo or a balance disorder. Our conclusion is that benign paroxysmal vertigo has a favorable outcome, and it is not a general precursor of migraine.

Infant care in rural Malawi. A prospective study of morbidity and growth in relation to environmental factors.

In connection with the introduction of piped surface water delivered by community taps in a rural area of Malawi, 46 infants were studied prospectively during a 10-month period to monitor infant care and health. Compared with the reference population, newborn infants generally weighed less and were shorter. Breastfeeding was universal and appeared adequate for catch-up in weight during the 1st 3 months. Growth faltering occurred from the age of 3 months when the prevalence of infectious diseases gradually increased and suitable supplementary foods were lacking. Babies were given highly contaminated water from the 1st days of life, but, in spite of this, diarrhoea was infrequent during the 1st 5 months when respiratory tract infections and episodes of fever were the most common symptoms of disease. Diarrhoea became a problem from the age of 5-6 months. No differences in morbidity or growth patterns were observed between infants using piped and traditional water sources. Thus, the quality of drinking water seemed to have no substantial effect on the health of the studied infants during the 1st months of life.

PIP: All 36 children (18 boys and 18 girls) born in 539 households from October 31, 1984, to February 28, 1985, were studied prospectively. In January 1985, 10 children (7 girls and 3 boys) born between January and April 1984 were also included. During visits, the mother was asked about disease during the preceding month and about feeding practices. The children had a clinical examination and nutritional assessment at each visit. 34 of 36 children began breast feeding within an hour of delivery. At 4 months, all 33 surviving children were still breast-fed. A thin maize gruel was introduced from as early as 2 days to as late as 4.5 months of age. At about 3 months, a thick maize porridge was started, and by 7 months 50% of the infants received this porridge. By May 1985, about 50% of the families (18/34) used piped water. During the first 6 months, the fever reported was significantly related to spleen size at the end of that month (p 0.05), suggesting malaria. Diarrhea gradually increased to an average of about 2 days per month by the age of 5-6 months and reached a peak of 4-5 days per month at the age of 11-12 months. During the first year of life, at least one symptom of disease was reported on 6 days per month on average. During the first 6 months, there was no difference in morbidity prevalence between infants whose families used piped water and infants whose families drew water from traditional sources. The growth rate during the first 6 months was significantly correlated with total morbidity, respiratory tract infections, diarrheal diseases and fever during the month (p 0.05). Four of the newborn children, 1 boy and 3 girls, died during the follow-up period of 7-10 months, giving an estimated probability of dying before 6 months of age of 112 per 1000. Further research is needed why, under apparently similar conditions, some children survive and others do not.

Childhood mortality in relation to nutritional status and water supply--a prospective study from rural Malawi.

In connection with the introduction of an improved method of water supply in rural Malawi, the nutritional status, morbidity, and mortality among 1,178 children under five were studied during three rainy and three dry seasons. Data were collected at fortnightly home interviews. Nutritional assessment was made twice a year. One hundred and thirty-seven of the children died during the study period, and the probability of dying before the age of five was estimated to 270 per 1,000 children. The mortality risk was related to weight for height (p less than 0.001) and height for age (p less than 0.01) as well as to upper arm circumference (p less than 0.001) and triceps skinfold (p less than 0.05). Mortality among children living in households using the new, piped-water supply tended to be lower than mortality for those using traditional water sources, although the difference was not statistically significant (relative risk 0.4, 95% confidence interval 0.1-1.3).

Child health and household water supply: a longitudinal study of growth and its environmental determinants in rural Malawi.

The growth of 1029 children under 5 years of age, in rural Malawi, was studied during 1 year before and 1 year after the introduction of a piped water supply system. The study was performed to evaluate the effect of socio-economic and environmental factors, especially water supply, on growth. In general, the first 2 years of life were highly liable to nutritional impairment. The seasonal variation of growth rate was most pronounced in children under 2 years. It was found that crowding, measured both as population density and as members per household, had a negative impact on the growth of younger children. In households utilizing piped water, children did not display significantly better growth when compared with children in households using traditional water sources. Although clean water in itself is vital, it was not enough to improve the growth of young children under the conditions that we have studied. It is suggested that, when providing an improved water supply, sanitation and hygiene education are necessary additions. Other ways of reducing recurrent infections, in combination with effective nutrition during and after episodes of disease, should also be given increased consideration in order to improve growth.

Water supply, sanitation and health education programmes in developing countries: problems of evaluation.

There are several methodological problems related to evaluating the impact that improved water supply, sanitation and health education projects have on public health. Fifteen studies of intervention programmes, one by the present authors, are discussed. Since non-intervention studies of water supply are difficult to assess, a valid study design must include an intervention programme, even though such studies are more costly and time-consuming. Detailed descriptions of programmes, study plans, and analytical methods are often lacking, and different studies reach greatly diverging conclusions. It may be proposed that studies based on "weak" methodology give a more positive impression of improved public health after improvement of water supply than do before-after studies using comparison groups.

Alternatives for harvesting cells grown on microcarriers: effects on subsequent attachment and growth.

In order to facilitate the subpassaging of cells in microcarrier cultures for scaling up culture volumes, alternative procedures for harvesting cells from microcarriers were investigated. A variety of enzymes including trypsin and dextranase were tested separately and in combination to evaluate cell viability after detachment, recovery, and subsequent attachment and growth of cells following inoculation of the cells in the next microcarrier culture. Treatment of confluent microcarriers with dextranase detached cells efficiently and with high viability and in addition totally digested the dextran-based matrix of Cytodex, thus avoiding the possible need to separate the harvested cells from the microcarriers. Dextranase alone resulted in cells harvested as sheets, but if used in combination with trypsin, a single cell suspension of harvested cells was obtained.

Alternative surfaces for microcarrier culture of animal cells.

As part of an effort to broaden the applicability and efficiency of microcarrier cell culture various alternative new microcarriers were synthesized. The microcarriers were compared as substrates for the growth of several types of cells and with respect to binding of proteins from the culture medium. Cross-linked dextran has been found to be the most suitable material for a microcarrier matrix and was used as the matrix for the new microcarriers. One type of microcarrier was synthesized so that the charges necessary for cell attachment were present only in the surface layer of the microcarrier in the form of N,N,N-trimethyl-2- hydroxyaminopropyl groups. The resulting microcarriers had a very low capacity to bind proteins from the culture medium (e.g. albumin and IgG) and such proteins could be removed from the cultures more efficiently than when using previous microcarriers. A new principle was used for the development of the other type of microcarrier. A surface layer of cross-linked denatured collagen provided the surface for growth of cells. These microcarriers provided a "natural" substrate for cell growth and allowed improved attachment and spreading of cells with epithelial morphology. Harvesting cells from these microcarriers with proteolytic enzymes was more efficient than with previous microcarriers. The two alternative microcarriers should result in improved process efficiency and have a potential value in the preparation of live vaccines.

Congenital neurofibromatosis. Multiple subcutaneous tumors with spontaneous regression in twins.

Multiple subcutaneous tumors were found at birth in a pair of identical twins, and the histological diagnosis was neurofibroma. The tumors disappeared within seven months. This disorder must be differentiated from congenital generalized fibromatosis, which usually shows a malignant course.

Harvesting and subculturing cells growing on denatured-collagen coated microcarriers (Cytodex 3).

Selecting correct procedures and conditions for harvesting cells was essential for successful subcultivation of cells when using the microcarrier culture technique. The proteolytic enzymes trypsin, Dispase and collagenase were compared with respect to the yield and the viability of Vero cells when harvested from Cytodex 3 microcarriers. Treatment with Dispase or trypsin resulted in similar viabilities but recovery after trypsin treatment was improved. The advantage of using collagenase was the improved plating efficiency of cells when subculturing to new microcarrier cultures. Pre-washing the confluent microcarriers with EDTA (0.02% w/v) improved the yield and the viability when harvesting with trypsin or collagenase. The stage of the culture cycle when cells were harvested did not influence relative recovery or viability. In contrast, significant differences in recovery and viability were found when harvesting cells grown in the presence of different batches of foetal calf serum. The results confirm that the choice of enzyme for harvesting depends upon the cell type and purpose of the culture.

Benign paroxysmal vertigo in childhood.

Fifteen children with a syndrome called benign paroxysmal vertigo are presented. This syndrome is characterized by attacks of vertigo of sudden onset lasting a few minutes and in extreme cases several hours or even up to 2 days. Additional symptoms are pallor, sweating, vomiting and nystagmus. Consciousness is not impaired. The attacks usually occur in the first 4 years of life. They are recurrent, the appearance varying from several times a week to once a year, and they may cease spontaneously after only months but usually years. The most important differential diagnoses are epilepsy and posterior fossa tumour. The etiology is unknown, but there may be a vascular disturbance affecting the posterior cerebral circulation with secondary disturbances of the vestibular nuclei.

Alternative surfaces for microcarrier culture of animal cells.

As part of an effort to broaden the applicability and efficiency of microcarrier cell culture various alternative new microcarriers were synthesized. The microcarriers were compared as substrates for the growth of several types of cells and with respect to binding of proteins from the culture medium. Cross-linked dextran has been found to be the most suitable material for a microcarrier matrix and was used as the matrix for the new microcarriers. One type of microcarrier was synthesized so that the charges necessary for cell attachment were present only in the surface layer of the microcarrier in the form of N,N,N-trimethyl-2-hydroxyaminopropyl groups. The resulting microcarriers had a very low capacity to bind proteins from the culture medium (e.g. albumin and IgG) and such proteins could be removed from the cultures more efficiently than when using previous microcarriers. A new principle was used for the development of the other type of microcarrier. A surface layer of cross-linked denatured collagen provided the surface for growth of cells. These microcarriers provided a "natural" substrate for cell growth and allowed improved attachment and spreading of cells with epithelial morphology. Harvesting cells from these microcarriers with proteolytic enzymes was more efficient than with previous microcarriers. The two alternative microcarriers should result in improved process efficiency and have a potential value in the preparation of live vaccines.

Child health and household water supply: an intervention study from Malawi

Children in households using improved water supply had significantly lower total morbidity and a tendency toward lower mortality than children in households using water from traditional sources. There was; however; no impact on diarrhoeal diseases; skin and eye infections or growth; which might be due to the fact that nutrition; environmental sanitation and hygiene remained unchanged. The impact of the intervention on total morbidity varied significantly between different villages; suggesting that there were other important factors influencing the effect of an improved water supply