Medical phototherapy in childhood skin diseases.

Phototherapy is used for the medical care of cutaneous conditions that do not respond to topical or systemic medical agents, and for conditions that require broad exposure to UV as a stabilizing agent for disease. Numerous wavelengths and delivery devices of ultraviolet light are used in childhood. This article is a brief overview of the medical usage of phototherapy in childhood. In the neonatal nursery blue light (459-460 nm) is used to reduce bilirubin levels and prevent kernicterus. While psoralens and UVA (PUVA) has been demonstrated to be efficacious in a variety of pediatric skin conditions, narrowband UVB therapy (311 nm) has largely replaced psoralens and UVA as initial choice in full-body phototherapy for children. The latter is easier to deliver, with less resultant erythema than systemic psoralens and UVA which requires strict use of 24 hour protective eyewear. Narrowband UVB is therefore preferred for stabilization and clearance of a variety of inflammatory and autoimmune conditions especially atopic dermatitis, psoriasis and vitiligo. Conditions with lymphocytic infiltration, including mycosis fungoides, alopecia areata and pityriasis lichenoides can improve with Narrowband UVB as well. Alternatively, localized delivery of Narrowband UVB can be performed using the excimer laser (308 nm), which has been described for the therapy of vitiligo and alopecia areata in childhood. Some diseases with dermal infiltration including morphea and mastocytosis may do better with Psoralens and UVA or UVA1. Delivery of psoralens can also be performed topically for said conditions and in the setting of alopecia areata, thereby limiting UVA exposure, while retaining efficacy. Phototherapy can be a helpful adjunct in pediatric skin disease, but is limited by compliance issues. Parents can act as partners in the safe and effective delivery of phototherapy by standing outside the booth or inside with the child to ensure lack of movement and to aid in maintenance of eyewear. Choice of type of phototherapy and close monitoring, with parental partnership, is the key to successful treatment.

The impact of dietary protein intake on serum biochemical and haematological profiles in vervet monkeys.

This study evaluated the influence of Westernised and traditional African diets on biochemical and haematological profiles in vervet monkeys (Cercopithecus aethiops). Twelve adult male vervet monkeys bred at the Medical Research Council, all over 4 years of age and weighing more than 5 kg each, were divided into two groups of six individuals. These monkeys were raised on a standard in-house diet post-weaning, before they were fed for 8 weeks on diets containing milk solids (17.2%) or maize + legume (17.4%), as sources of high crude protein (+/- 3.5 g/kg). High protein diets had no significant effect on serum biochemical indices such as aspartate aminotransferase (AST) and gamma glutamyl transferase (GGT) concentrations (P > 0.10). However, alanine aminotransferase (ALT) concentrations were significantly higher during week 8 (P < 0.05) for the maize + legume protein group. Alkaline phosphatase (ALP; P < 0.07), total protein (P < 0.0001), albumin (P < 0.02), and bilirubin (P < 0.003) were elevated in the milk solids group, while glucose levels were also significantly higher for the milk solids group (P < 0.05) between weeks 2 and 6. Elevated protein intake had no significant effect on haematological parameters such as red blood cells (RBC), platelet and white blood cell (WBC) counts, haemoglobin levels and monocyte and neutrophil concentrations (P > 0.10). In contrast, serum lymphocyte levels were significantly raised in the maize + legume protein group (P = 0.03), whereas values for the haematocrit (P < 0.002), mean cell volume (MCV; P < 0.03) and mean corpuscular haemoglobin concentration (MCHC; P < 0.0001) were higher in the monkeys that were fed the milk solids. This investigation showed that the type of dietary protein that is consumed may well affect certain biochemical and haematological indices in vervet monkeys. Compared to the group that were given the traditional African food regime, the animals on the Western-type milk solids diet showed significant elevations in a number of important biological indicators. However, longer-term studies should be completed in this area if we are to make firmer conclusions regarding the link between the nature of dietary proteins that are consumed and its effect on metabolism.

Effect of dietary plant and animal protein intake on sperm quality in monkeys.

This study was conducted to evaluate the influence of animal and plant protein diets on sperm quality indices over 120 days, using the vervet monkey (Cercopithecus aethiops), as a model. These experiments were divided into a 60-day period of high-protein consumption (+/-17% crude protein), followed by a 60-day term of sustainable protein intake (+/-9% crude protein). All the diets were designed to be similar, except for the source of dietary protein that the animals consumed. High-protein diets containing milk solids or maize + legumes had no significant effect on sperm quality parameters over the first 60 days. During the next 60 days of the investigation, sustainable plant and animal protein diets had differential effects on a number of sperm quality indices. When compared to the plant-based diet, the monkeys that were given the animal protein diet containing milk solids had lower sperm counts (p < .04), reduced sperm motility (p = .04), higher sperm midpiece abnormalities (p < .05), and a trend (p = .10) towards increased sperm head defects. These findings shed some light on the impact of variable dietary proteins on sperm quality, but should be followed by longer-term investigations around this important reproductive health issue.

Antimicrobial resistance of bacterial flora associated with bovine products in South Africa.

The administration of subtherapeutic doses of antibiotics to livestock introduces selective pressures that may lead to the emergence and dissemination of resistant bacteria. This study determined the antibiotic-resistance spectra of the microbial flora found on freshly slaughtered and retail beef and in unpasteurized and pasteurized packaged milk. Staphylococci, Enterobacteriaeae, and isolates from total aerobic plate counts were tested for resistance to vancomycin, streptomycin, methicillin, tetracycline, and gentamicin using the disc diffusion susceptibility test and resistance to penicillin was determined by using oxacillin. A larger proportion of resistance to most antibiotics, except for vancomycin, was displayed by isolates from abattoir samples. The incidence of multiple antibiotic resistance (MAR) pathogenic bacteria is also higher in the abattoir. Resistance genes lost because of lack of selective pressure or resistant flora being replaced by more sensitive flora during processing is the reason for the lower incidence of MAR pathogenic bacteria among retail samples. These resistant bacteria can be transferred to humans through the consumption of rare or raw beef and unpasteurized milk, thus rendering the resultant food-related infections difficult to treat. The present findings clearly demonstrate that antibiotic-resistant bacteria in beef and milk pose a serious problem in South Africa.

The influence of dietary crude protein intake on bone and mineral metabolism in sheep.

Increased dietary protein consumption is thought to cause calciuresis, a negative calcium balance and increased bone loss that may result in skeletal deformities and fracture. To explore this hypothesis, 40 approximately 100-day-old meat-type Merino ram lambs were fed, for 6 months, diets with an increasing crude protein (CP) content (114, 142, 171 and 190 g/kg DM) but approximately on an iso-nutrient basis with regard to metabolisable energy, calcium and phosphorus. Increased protein consumption modestly (NS) enhanced calciuresis and resulted in significant (P < or = 0.01) limb skewness. This could not, however, be ascribed to osteopaenic bones, and compared with animals consuming lower protein rations, the bone mineral density (BMD) and vertebral trabecular bone volume of animals fed high protein diets were significantly increased: the BMD of thoracic vertebrae was positively related to the CP intake (r = 0.62; P < or = 0.001). In animals consuming higher protein diets, skeletal radiology and quantitative bone histology revealed no evidence of increased bone turnover as would be expected in animals that are in negative calcium balance. No relationship existed between limb skewness and the growth rate of lambs. However, the ratio of Ca:P in the forelimb (r = -0.98), vertebrae (r = -0.72) and rib (r = -0.42) was found to be inversely correlated with increased protein intake and resulted from an increase in the phosphorus content of bone, while the amount of bone calcium was unaffected. We conclude that qualitative micro-architectural abnormalities, and not mere bone loss, may underlie the skeletal deformities induced by increased protein consumption in sheep.

The effect of dietary protein on the mineral status of vervet monkeys with special reference to the impact of milk solids on calcium excretion.

This study assessed the impact of Westernised and traditional African diets on mineral metabolism in general and calcium status in particular in vervet monkeys. Twelve adult male vervet monkeys (Cercopithecus aethiops), with an average weight of 5+/-0.58 kg each, were divided into two groups of six individuals each and fed traditional diets containing largely maize + legumes (17.4%) or Westernised diets containing milk solids (17.2%) as the source of high crude protein for 8 weeks. Blood was taken at 2-week intervals, the animals were weighed, while urine and stool samples were collected over 24 hours. The monkeys on the milk solids diet had diarrhoea for 6 weeks post-dietary intervention, and produced significantly greater quantities (P<0.02) of stool. These animals also produced significantly more urine (P<0.02). There was no difference in the degree of calciuresis of the two groups, but the monkeys on maize + legume proteins absorbed significantly more calcium during weeks two and six (P<0.04). Furthermore, both groups of monkeys showed a significant decline in plasma calcium levels over the experimental period (P<0.001). The diets had no effect on phosphate levels in the plasma or urine. However, both groups of animals absorbed less phosphate (P<0.09). There was an increasing loss of urinary magnesium (P = 0.03) in both groups, with the milk solids group showing lower plasma levels of this element (P = 0.09). However, the milk solids group lost less magnesium through the stool (P<0.03). In addition, the animals on milk solids showed significant natriuresis (P<0.05), while plasma sodium levels in both groups declined over time (P<0.03). Both diets induced a state of urinary potassium loss (P = 0.0003) and decrease in plasma potassium (P<0.0002). Urinary pH and plasma urea were unaffected by the diets, but the monkeys on maize + legumes excreted significantly less (P<0.001) urinary urea. This study indicates that the milk solids diet compromised mineral homeostasis by interfering with gut and renal functioning, while the traditional African diet did not induce these effects.

Antimicrobial resistance of bacteria isolated from slaughtered and retail chickens in South Africa.

Animal feed is increasingly being supplemented with antibiotics to decrease the risk of epidemics in animal husbandry. This practice could lead to the selection for antibiotic resistant micro-organisms. The aim of this study was to determine the level of antibiotic resistant bacteria present on retail and abattoir chicken. Staphylococci, Enterobacteriaceae, Salmonella and isolates from total aerobic plate count were tested for resistance to vancomycin, streptomycin, methicillin, tetracycline and gentamicin using the disc diffusion susceptibility test; resistance to penicillin was determined using oxacillin. Results from the antibiotic code profile indicated that many of the bacterial strains were displaying multiple antibiotic resistance (MAR). A larger proportion of resistance to most antibiotics, except for vancomycin, was displayed by the abattoir samples, therefore suggesting that the incidence of MAR pathogenic bacteria was also higher in the abattoir samples. This resistance spectrum of abattoir samples is a result of farmers adding low doses of antibiotics to livestock feed to improve feeding efficiency so that the animals need less food to reach marketable weight. The lower incidence of MAR pathogenic bacteria in the retail samples is a result of resistance genes being lost due to lack of selective pressure, or to the fact that the resistant flora are being replaced by more sensitive flora during processing. The use of subtherapeutic levels of antibiotics for prophylaxis and as growth promoters remains a concern as the laws of evolution dictate that microbes will eventually develop resistance to practically any antibiotic. Selective pressure exerted by widespread antimicrobial use is therefore the driving force in the development of antibiotic resistance. This study indicated that a large proportion of the bacterial flora on fresh chicken is resistant to a variety of antibiotics, and that resultant food-related infections will be more difficult to treat.

A new high-resolution esophageal electrocardiography recording technique: an experimental approach for the detection of myocardial ischemia.

UNLABELLED: Criteria for ischemic changes in the esophageal electrocardiograph (E-ECG) have not been standardized and validated. The main goal of this study was to evaluate the experimental esophageal recording of myocardial ischemia and to assess the association between ST segment alternans in the E-ECG and ischemia. Experiments were performed on 18 anesthetized sheep with occlusion of a branch of the left anterior descending artery. The bipolar signals were recorded via an esophageal lead containing three chloridized silver electrodes. Electrical signals were amplified in a self-designed, battery-supported preamplifier (gain 1000, frequency range 0.01-2000 Hz, common mode rejection 140 dB, signal noise 5-7 microV p-p), then sent to a digital oscilloscope for display and to a pulse code-modulated recorder. Surface electrocardiography (S-ECG) data were also recorded. Ischemia E-ECG revealed homogenous ST segments without any beat-to-beat alternans. Two minutes after occlusion, 14 of 15 sheep (93%) showed repetitive beat-to-beat fluctuations within the ST segment on the E-ECG. Of the 15 sheep, 7 (47%) showed ischemia in the S-ECG (P < 0.01). For calculation of the dynamic changes in the ST segment in the E-ECG, the difference in the amplitudes of the ST segment of five successive beats to the next beat, performed for 200 consecutive beats, was calculated. The central tendency of the sum of these values before versus during ischemia was 2000 mV/ms versus 5000 mV/ms (Hodges-Lehmann point estimator) (95% confidence intervals 1700/2500 versus 3350/9250 [lower limit/upper limit]). The authors have established a close temporal relationship between the magnitude of ST segment alternans recorded via E-ECG and myocardial ischemia. IMPLICATIONS: The study presents the use of an esophageal electrocardiograph for detection of progressive changes of myocardial ischemia and infarction. During acute myocardial ischemia and infarction in sheep, the esophageal electrocardiograph has visually apparent ST alternans of amplitude in the millivolt range, in part due to a special amplifier (0.01-2000 Hz). This is therefore one very promising technique for better evaluation of electrocardiographic changes of ischemia.

The effects of external mechanical stimulation on the healing of diaphyseal osteotomies fixed by flexible external fixation.

OBJECTIVE: The purpose of this study was to investigate the effect of an externally applied mechanical stimulus on fracture healing under flexible fixation. DESIGN: Stimulation of fracture healing under various conditions of interfragmentary movement in an in vivo fracture model on 41 sheep. BACKGROUND: It is generally accepted that small interfragmentary movements (IFMs) yield better bone healing results than larger IFMs (> 1 mm). However, the optimal size of IFM within the 1-mm range remains undetermined. METHODS: Standardized transverse osteotomy of 3 mm gap size in the left ovine tibia was fixed with an unilateral external fixator. The sheep were divided into four IFM groups of 0.0, 0.2, 0.4 and 0.8 mm and stimulated with this amplitude for 1200 cycles per day at 1 Hz. After a healing period of 6 weeks, bone mineral density and biomechanical stability were evaluated to determine the quality of healing. RESULTS: The amount of callus formation increased significantly with increasing IFM (P <0.05). However, highest biomechanical stability of the healed bone and mineral density of the gap tissue was achieved with an IFM of 0.4 mm, although the differences were not significant. CONCLUSIONS: These results suggest that the optimal interfragmentary movement for acceleration of delayed fracture healing is in the range of 0.5 mm. However, the enhancement of the healing of flexibly-fixed fractures by external application of interfragmentary movement is limited. RELEVANCE: In this model the external application of a mechanical stimulus in addition to the stimulation caused by normal loading and the flexibility of the fixation did not enhance the healing process significantly. It appears that the external application of interfragmentary motion is promising perhaps only for patients unable to stimulate their fracture healing by weight-bearing.