Growth of vascularized composite mandibular allografts in young rabbits

Forty-one hemimandible allografts were transplanted in young rabbits immunosuppressed with cyclosporine. The majority of the grafts demonstrated normal wound healing, and growth of hair, bone, and teeth. The mandibular body and the premolars showed significant growth in length. The allografted mandibles functioned sufficiently that the rabbits took oral nourishment soon after surgery. Long-term survival was limited by a toxic "wasting syndrome" specific for rabbits under treatment with cyclosporine.     

The use of an antibiotic-impregnated spacer block for revision of the septic total knee arthroplasty

Through the use of an antibiotic-impregnated polymethylmethacrylate spacer block in two-stage exchange arthroplasty, the chronically infected total knee arthroplasty can, in most cases, be effectively salvaged. In a review of 28 such consecutive cases by a single surgeon, all revised implants were retained except one which required arthrodesis. In the remaining cases, mean Hospital for Special Surgery knee scores were 86, with mean total range of motion of 90 degrees . All wounds healed eventually, and seven patients were thereafter able to undergo other total joint arthroplasties. Advantages of this technique included maintenance of ligamentous balance as well as bone stock with weight bearing, local antibiotic delivery, and facilitation of reimplantation.     

Intravenous drug users and AIDS: risk behaviors

Risk-taking behaviors were studied in this assessment of 345 intravenous drug users from Baltimore, El Paso, and Denver. Over 50% reported injecting drugs daily and 70% shared needles with others, averaging 6.3 partners. In addition, 86% had shared a "cooker" and nearly 50% injected in a "shooting gallery." More than half of the males sampled had two or more sex partners, including 18% with five or more. Females averaged 19 sex partners in the preceding 6 months, with 22% reporting sex with five or more. Two-thirds of the total sample never used a condom, while only 6% always used this form of protection. On the other end of this risk continuum were those subjects who did not share needles or always cleaned their needles with an effective agent, had no sexual relations or always used a condom. Subjects following such practices could be considered low risk if they adopted safe behaviors in other associated areas of their lives. However, in an analysis of total risk, it was found that only 14 subjects (4%) practiced safe needle use and safe sex. Despite these findings, some encouraging results were seen. In an analysis of risk according to location, Baltimore subjects were significantly less at risk according to number of needle-sharing partners, borrowing needles, sharing a "cooker," injection in a "shooting gallery," cleaning needles, use of disinfectants, number of sexual partners, and use of condoms than either their cohorts in El Paso or Denver. Street outreach to modity risk behaviors among IVDUs began in Baltimore approximately 2 years prior to funding in El Paso and Denver. These results suggest that there may be a potential to moderate risk through intervention.     

Fatal meningoencephalitis due to Bacillus anthracis

Abstract: We report the first case of fatal anthrax meningoencephalitis in Hong Kong over the past 60 years. A 13 year-old boy presented with right lower quadrant pain, diarrhoea and progressive headache. Lumbar puncture yielded gram positive bacilli initially thought to be Bacillus cereus, a contaminant. He was treated with ampicillin and cefotaxime, but died 3 days after hospitalization. The organism isolated from blood and cerebrospinal fluid was later identified as Bacillus anthracis.     

Survival and developmental disability in infants with birth weights of 501 to 800 grams, born between 1979 and 1994

OBJECTIVE: Because the survival rate has increased for extremely low birth weight neonates, many have raised the concern that the rate of developmental disability among survivors will also increase. To address this concern, we analyzed changes over time in survival and major neurosensory impairment in a sample of extremely low birth weight infants born between July 1, 1979, and June 30, 1994. METHODS: The study sample included 513 infants with birth weights of 501 to 800 g who were cared for in either of the two neonatal intensive care units that serve a 17-county region in northwest North Carolina and who were born to mothers residing in that region. At 1 year of age (corrected for gestation), survivors were examined by a pediatrician and were tested using the Bayley Scales of Infant Development. Major neurosensory impairment was defined as cerebral palsy, a Bayley Mental Developmental Index <68, or blindness. A total of 209/216 (97%) of survivors were examined at 1 year of age. Epoch of birth was defined as follows: epoch 1, July 1, 1979 to June 30, 1984; epoch 2, July 1, 1984 to June 30, 1989; and epoch 3, July 1, 1989 to June 30, 1994. RESULTS: Survival rates for epochs 1, 2, and 3 were, respectively, 24/120 (20%), 63/175 (36%), and 129/218 (59%). In contrast, the proportions with a major neurosensory impairment did not increase over time; rates for successive epochs were 6/24 (25%), 17/61 (28%), and 26/124 (21%). Rates of cerebral palsy were 3/24 (13%), 12/61 (20%), and 9/124 (7%); rates of delayed mental development were 4/24 (17%), 12/61 (20%), and 17/124 (14%); and rates of blindness were 2/24 (8%), 0/62, and 5/124 (4%), respectively. CONCLUSIONS: This analysis suggests that the increasing survival of extremely low birth weight neonates since the late 1970s has not resulted in an increased rate of major developmental problems identifiable at 1 year of age.     

Chromosome aberrations in coeliac and non-coeliac enteropathies

The frequency of chromosomal aberrations in peripheral blood lymphocytes was assessed in three groups of children: untreated coeliac disease (n = 20); non-coeliac disease enteropathies (n = 15); controls (n = 15). The mean frequency of aberrant cells and the total number of aberrations per 100 metaphases was increased in the coeliac disease group compared with controls by factors of 5 and 6, respectively (p < 0.01 for both). Aberrant cells and total aberrations were similarly increased in the non-coeliac disease enteropathy group by a factor of 3.7 in each case (p < 0.05). However, the frequency of aberrations in the two enteropathy groups was not significantly different. Children with coeliac disease, similar to affected adults, have evidence of increased chromosomal instability. However, similarly increased chromosomal aberrations are seen in children with non-coeliac disease enteropathies, indicating that the abnormality is not specific for coeliac disease.     

Does a single plasma phenylalanine predict quality of control in phenylketonuria?

A 1993 MRC working group on phenylketonuria suggested standardising blood phenylalanine measurements by taking blood samples at the same time each day. Since it is not known how representative of a 24 hour period a single phenylalanine concentration is, the aim of this study was to investigate the 24 hour variability of plasma phenylalanine in well controlled children with phenylketonuria. Sixteen subjects, 12 girls and four boys aged 1 to 18 years, had hourly venous blood samples collected for 13 hours between 09.00 and 21.00 on one day. Serial skin puncture blood specimens were then collected at 24.00, 03.00, and 06.00 within the same 24 hour period. All food and drink was weighed. The median variation in plasma phenylalanine concentration was 155 mumol/l/day, with a minimum of 80 and a maximum of 280. The highest concentration occurred in the morning between 6.00 and 9.00 in 63% of subjects; the lowest occurred between midday and midnight in 94%. Concentrations < 100 mumol/l occurred in 46% of children below 11 years, three having concentrations < 30 mumol/l for two, six, and seven hours respectively. Three of five subjects had concentrations above the MRC guidelines for 24% of the period studied. Except in two subjects, the blood concentrations did not rise in response to phenylalanine consumption. However, the greater the quantity of protein substitute taken between waking and the 16.00 specimen, the larger the decrease in daytime phenylalanine concentration (r = -0.7030) (p < 0.005). There is therefore wide variability in phenylalanine concentrations in a 24 hour period in children with phenylketonuria which is not reflected in a single observation. Further study is needed to investigate the effects of timing of protein substitute on the stability of phenylalanine concentrations.     

Management of colorectal cancers

The management of colorectal cancers, published in a recent issue of Effective Health Care, is reviewed.     

Subarachnoid meperidine (Pethidine) causes significant nausea and vomiting during labor. The Duke Women's Anesthesia Research Group

BACKGROUND: The combined spinal-epidural (CSE) technique using bupivicaine-fentanyl has become an established method of pain control during parturition. One limitation is the relatively short duration of effective analgesia produced by bupivicaine-fentanyl. In contrast, subarachnoid meperidine has been shown to provide a long duration of anesthesia in nonobstetric patients. Therefore, the authors tested the hypothesis that subarachnoid meperidine produces a significant increase in the duration of analgesia compared with bupivicaine-fentanyl. METHODS: Based on a power analysis of preliminary data, the authors intended to recruit 90 patients for the study, randomized to three groups: 2.5 mg bupivicaine-25 microg fentanyl, 15 mg meperidine, or 25 mg meperidine. However, after enrolling 34 patients, the study was discontinued because of a significant increase in nausea or vomiting in the study patients. RESULTS: Nausea or vomiting was substantially increased in both meperidine groups compared with the bupivicaine-fentanyl group: 16 with nausea or vomiting in the meperidine groups (n = 21), compared with 1 in the bupivicaine-fentanyl group (n = 11), P = 0.0011. The mean duration of analgesia provided by 25 mg meperidine was 126 +/- 51 min, compared with 98 +/- 29 min for bupivicaine-fentanyl and 90 +/- 67 min for 15 mg meperidine. These data were not significant (P = 0.27). CONCLUSIONS: Although intrathecal meperidine could potentially prolong subarachnoid analgesia during labor, its use was associated with a significant incidence of nausea or vomiting. These data do not support the use of subarachnoid meperidine in doses of 15 or 25 mg for labor analgesia.     

The rheological properties of self-emulsifying systems, water and microcrystalline cellulose.

The rheological properties of mixtures of equal parts of a range of ratios of a self-emulsifying system (MP) and water (W) added to microcrystalline cellulose (MCC), have been measured by an extrusion capillary rheometer. These measurements allow assessment of both the shear and tension components of flow plus the elastic behaviour of the wet powder masses, although the results for the estimation of shear stress require careful interpretation due to the limitation of the measuring system and the assumptions made in their derivation. The results indicate that there are three regions of behaviour of the systems, which are all significantly different from the mixtures containing only W and MCC. At low MP contents (1.5--23%), the masses increase in their resistance to shear and elongational flow and have lower elasticity. These similarities in behaviour occur in spite of considerable increase in the viscosity of the MPW mixtures and a change to non-Newtonian flow of the fluid. The behaviour of the 46% MP system is intermediate between these systems and the high MP concentrations (69, 80 and 92%). These latter systems show less resistance to shear and elongational flow than the first group of concentrations, but show considerably higher levels of elasticity. As the resistance to shear decreases, so does the impairment of the surface of the extrudate. There is clear evidence of a systematic change in behaviour of the wet powder masses as the values for the angle of entry of the wet mass into the die when plotted against the ratio of the resistance to die entry (upstream pressure loss) to the shear stress within the die, is linear on a log/log scale. Also, the values of compliance of the systems as a function of shear stress fall on a common curve. Changes in the ratio of the MPW to MCC for a system for a single level of MP (46%) resulted in a change in the values of the rheological parameters but not the type of behaviour. As all these wet powder masses had been shown previously to form pellets by the process of extrusion/spheronization, it is clear that systems with a wide range of rheological characteristics can be processed and no single rheological parameter can be used to provide complete characterisation of the processability of such systems.