Assessment of the quality of neonatal echocardiographic images transmitted by ISDN telephone lines

OBJECTIVE

To assess the quality of echocardiographic images from neonates transmitted over Integrated Service Digital Network 2 (ISDN2) channels.

DESIGN

Echocardiographic images were viewed live in real time either by a direct video link or by transmission over the commercial network, using one, two, or three ISDN2 channels. The order of the viewing formats was random and four observers marked each view for potential for provision of complete diagnostic information and quality.

SETTING

Cardiology department of tertiary referral centre for paediatric cardiac services. ISDN lines were positioned in two nearby rooms. Telephone connection was through the commercial network and video connection by a direct video cable.

PATIENTS

10 neonates were studied (weight 2600 to 3900 g). In each, nine echocardiographic studies were undertaken to assess imaging (M mode and cross sectional) and Doppler (spectral and colour) quality.

RESULTS

No significant differences were found in diagnostic ability between the different formats for M mode, colour, or spectral Doppler studies. For cross sectional imaging the diagnostic information and image quality increased with increasing numbers of ISDN channels. With six channels there was little difference from the directly connected images.

CONCLUSIONS

In echocardiographic assessment of the newborn, one or two ISDN2 channels will transmit images of satisfactory quality in many situations but three or more channels are necessary to ensure minimum degradation of the live image.

Effects of oral chlortetracycline and dietary protein level on plasma concentrations of growth hormone and thyroid hormones in beef steers before and after challenge with a combination of thyrotropin-releasing hormone and growth hormone-releasing hormone

The objective of this study was to determine the effect of a subtherapeutic level of chlortetracycline (CTC) fed to growing beef steers under conditions of limited and adequate dietary protein on plasma concentrations of GH, thyroid-stimulating hormone (TSH), and thyroid hormones before and after an injection of thyrotropin-releasing hormone (TRH) + GHRH. Young beef steers (n = 32; average BW = 285 kg) were assigned to a 2x2 factorial arrangement of treatments of either a 10 or 13% crude protein diet (70% concentrate, 15% wheat straw, and 15% cottonseed hulls) and either a corn meal carrier or carrier + 350 mg of CTC daily top dressed on the diet. Steers were fed ad libitum amounts of diet for 56 d, and a jugular catheter was then placed in each steer in four groups (two steers from each treatment combination per group) during four consecutive days (one group per day). Each steer was injected via the jugular catheter with 1.0 microg/kg BW TRH + .1 microg/kg BW GHRH in 10 mL of saline at 0800. Blood samples were collected at -30, -15, 0, 5, 10, 15, 20, 30, 45, 60, 120, 240, and 360 min after releasing hormone injection. Plasma samples were analyzed for GH, TSH, thyroxine (T4), and triiodothyronine (T3). After 84 d on trial, the steers were slaughtered and the pituitary and samples of liver were collected and analyzed for 5'-deiodinase activity. Feeding CTC attenuated the GH response to releasing hormone challenge by 26% for both area under the response curve (P<.03) and peak response (P<.10). Likewise, CTC attenuated the TSH response to releasing hormone challenge for area under the response curve by 16% (P<.10) and peak response by 33% (P<.02), and attenuated the T4 response for area under the curve by 12% (P<.08) and peak response by 14% (P<.04). Type II deiodinase activity in the pituitary was 36% less (P<.02) in CTC-fed steers than in steers not fed CTC. The results of this study are interpreted to suggest that feeding subtherapeutic levels of CTC to young growing beef cattle attenuates the release of GH and TSH in response to pituitary releasing hormones, suggesting a mechanism by which CTC may influence tissue deposition in cattle.

Long-term outcome after selective posterior rhizotomy in children with spastic cerebral palsy

A retrospective analysis of data collected prospectively was performed to determine the long-term outcome of lumbosacral selective posterior rhizotomy (SPR) in children with spastic cerebral palsy (CP). The study population comprised children with spastic CP, who had SPR more than 4 years prior to the time of the study and had quantitative standardized assessments of lower limb spasticity (Ashworth scale), range of motion measured goniometrically, muscle strength (MRC scale) and ambulatory function, both preoperatively and at 1 year after SPR. Children meeting these criteria were reassessed at 5 years after SPR using the same measures. Hip adductor spasticity, hip abduction range of motion and quadriceps strength were chosen as the primary outcome measures for statistical analysis. Of 80 patients who met the entry criteria for the study, 33 completed the 5-year assessments. Significant improvements in spasticity, range of motion and muscle strength were noted both at 1 year and at 5 years after SPR. The preoperative, 1-year and 5-year values were as follows: hip adductor spasticity (Ashworth scale) = 4.1, 2.1, 2.2; hip abduction range of motion (degrees) = 20.4, 39.9, 31.7, and quadriceps strength (MRC scale) = 3.6, 4.0, 4.1. Ambulatory function seemed to be better at 1 and 5 years compared to baseline, but no statistical analysis was done for this secondary outcome measure. It was concluded that improvements in lower limb motor outcome are present at 1 year after SPR, and that these improvements are generally maintained at 5 years.

Increased expression of matrix metalloproteinase-1 in osteocytes precedes bone resorption as stimulated by disuse: evidence for autoregulation of the cell's mechanical environment?

An in vivo animal model of bone adaptation was used to examine a possible role for matrix metalloproteinase-1 in the local mediation of bone remodeling: to corrode the coupling of osteocytes to the matrix in an attempt to autoregulate the cell's perception of its mechanical environment. Twelve young (12-16 months old) skeletally mature turkeys were separated into groups to be studied for stimulus periods of either 3 or 30 days. In each animal, the left ulna was functionally isolated and subjected to either disuse or 3,000 microstrain at 1 Hz for 10 minutes per day. The right ulna remained intact and served as an intra-animal control. No significant differences in bone area were detected at 3 days; however, ulnae subjected to disuse lost 8 +/- 4% (+/-SD) of bone area by 30 days. Over the same period, ulnae subjected to the mechanical stimulus gained 21 +/- 9% of bone area. With use of in situ reverse transcription-polymerase chain reaction, less than 2% of the osteocytes examined from the intact control ulnae stained positively for matrix metalloproteinase-1 mRNA. An antibody raised against matrix metalloproteinase-1 revealed no positively labeled osteocytes in the intact ulnae. This low percentage of osteocytes expressing matrix metalloproteinase-1 mRNA was similar to that seen in ulnae subjected to the osteogenic mechanical stimuli. In contrast, ulnae subjected to either 3 or 30 days of disuse showed evidence of matrix metalloproteinase-1 mRNA activity in a high percentage of osteocytes (89 +/- 5 and 66 +/- 8%, respectively; each time point significantly different from intact ulnae, as well as from each other, p < 0.05). The percentage of osteocytes labeled with the anti-matrix metalloproteinase-1 antibody was also highly elevated following 3 days of disuse (74 +/- 17%). These data demonstrate that an early response of bone to disuse is the upregulation of matrix metalloproteinase-1 activity in osteocytes. It is proposed that this upregulation of collagenase activity is indicative of the cell's degradation of coupling to the matrix, and it thus reflects the osteocyte's regulation of its own mechanical environment. We believe that such autoregulation of the osteocyte's physical environment will accommodate subtle changes in the bone's functional environment without the need to add or resorb bone tissue.

The New Zealand Socioeconomic Index: developing and validating an occupationally-derived indicator of socio-economic status

OBJECTIVE

Following revision of the international standard classification (ISCO88), to update and validate on health data an occupationally derived indicator of socio-economic status (SES) adapted to changing occupational and demographic conditions.

METHOD

The development of the New Zealand Socioeconomic Index (NZSEI) is based on a 'returns to human capital' model of the stratification process and uses data from the 1991 New Zealand Census (n = 1,051, 926) to generate scores for 97 occupational groups. The construct validation of the scale is carried out on data from the 1992-93 nationwide Household Health Survey (n = 3,000) using three health indicators (self-assessed health, cigarette smoking, general practitioner visits).

RESULTS

In general, the results are consistent with expected socio-economic patterns drawn from the literature for the three indicators.

CONCLUSIONS

While further work is required on a number of methodological and conceptual issues, the NZSEI provides a robust, standardised and internationally comparable occupational scale of SES for both males and females in either full- or part-time employment.

IMPLICATIONS

The NZSEI can be used on routinely collected occupational data. It has a clear conceptual rationale, updates existing SES scales, and provides a link to international standards in SES and occupational classification.

Enhancement of fracture healing by low intensity ultrasound

Fracture healing is a highly complex regenerative process that is essentially a replay of developmental events. These events include the action of many different cell types, a myriad of proteins, and active gene expression that in the majority of cases ultimately will restore the bone's natural integrity. Several biologic and biophysical approaches have been introduced to minimize delayed healing and nonunions, some with promising results. One example of such an approach is low intensity pulsed ultrasound, a noninvasive form of mechanical energy transmitted transcutaneously as high frequency acoustical pressure waves in biologic organisms. Numerous in vivo animal studies and perspective double blind placebo controlled clinical trials have shown that low intensity ultrasound is capable of accelerating and augmenting the healing of fresh fractures. Preliminary evidence suggests efficacy in the treatment of delayed healing and nonunions as well. This article reviews the animal and clinical studies that consider the effects of ultrasound on fracture healing, and the in vivo and in vitro work that strives to identify the biologic mechanism(s) responsible for the ultrasound induced enhancement of osteogenesis and fracture healing.

Role of heat shock proteins in the pathogenesis of cystic fibrosis arthritis

BACKGROUND

Arthritis is a well recognised complication of cystic fibrosis. The cause of this arthritis is not yet clear but it is likely to be an immunological reaction to one of the many bacterial antigens to which the lungs are exposed. One such group, the heat shock proteins, (hsp), was investigated. These are immunodominant antigens of a wide variety of infectious microorganisms and have varying amino acid chain sequences, some of which are similar to those found in human tissues.

METHODS

Antibodies to human hsp 27 and hsp 90 in the serum of patients with cystic fibrosis, with and without arthritis, and in normal age and sex matched healthy controls were measured. The severity of the cystic fibrosis was assessed by lung function tests and chest radiographs. The nature of the organisms colonising the lungs was determined by bacteriological examination of sputum.

RESULTS

Higher mean titres of serum IgG anti-human hsp 27 and hsp 90 antibodies were found in 50 patients with cystic fibrosis than in healthy controls (hsp 27, 0.25 (95% CI 0.19 to 0.33) versus 0.05 (95% CI 0.04 to 0.07); hsp 90, 0.27 (95% CI 0.22 to 0.32) versus 0.11 (95% CI 0.08 to 0.14)). These antibodies were higher in patients in whom the lungs were colonised with Pseudomonas aeruginosa than in those without infection (hsp 27, 0.41 (95% CI 0.17 to 0.63) versus 0.18 (95% CI 0.10 to 0.27); hsp 90, 0.37 (95% CI 0.18 to 0.57) versus 0.22 (95% CI 0.16 to 0.29)). The eight patients with cystic fibrosis with arthritis had higher anti-hsp 27 antibodies (0.48 (95% CI 0.13 to 0.92)) than the 42 patients without arthritis (0.22 (95% CI 0.17 to 0.30)).

CONCLUSIONS

These findings suggest that the arthritis associated with cystic fibrosis, despite being seronegative for rheumatoid factor, was associated with more severe lung disease and with a greater inflammatory response to heat shock proteins.

Pressure regulates osteoclast formation and MCSF expression in marrow culture

One of the forces generated during skeletal loading is hydrostatic pressure. In the work presented here, the ability of increased pressure to influence recruitment of osteoclasts was evaluated. Murine marrow cultures, with pO2 and pCO2 kept constant, were subjected to either control (1.0 atm) or elevated (1.37 or 2.0 atm) hydrostatic pressure. As compared to control, cultures pressurized for 6 days at 1.37 atm formed less osteoclast-like cells (OCLC) (71 +/- 6% of control, P < 0.0001). A similar degree of inhibition occurred in cultures exposed to pressure during days 2-4 only (62 +/- 6%), while treatment during days 5-7 failed to inhibit the OCLC number relative to control (99 +/- 5%). Delivery of 2.0 atm pressure on days 2-4 generated 52 +/- 4% OCLC compared to control. Since macrophage colony stimulating factor (MCSF)-dependent proliferation of osteoclast precursors occurs during the pressure-sensitive period, semiquantitative RT-PCR for MCSF mRNA was performed after 3 days in 1.37 atm (days 2-4). As compared to controls, pressure caused a decrease in mRNA coding for the membrane bound form of MCSF (71.2 +/- 4% (n = 25, P < or = 0.05), while the MCSF RT-PCR product representing the secreted form showed no consistent change. This lack of response of the soluble MCSF RT-PCR product was expected, as levels of bioassayable MCSF were not altered by pressure. Extrapolating these data to in vivo conditions suggests that load-bearing will inhibit the formation of osteoclasts.

Differentiation of the bone-tissue remodeling response to axial and torsional loading in the turkey ulna

The ability of bone tissue to differentiate between axial and torsional loading was determined with use of a functionally isolated turkey-ulna model of bone adaptation. Surface modeling and intracortical remodeling were quantified after four weeks of 5000 cycles per day of axial loading sufficient to cause 1000 microstrain normal to the long axis of the bone (five ulnae), 5000 cycles per day of torsional loading sufficient to cause 1000 microstrain of shear strain (five ulnae), or disuse (six ulnae). Of these three distinct regimens, only disuse caused a significant change in gross areal properties (12 per cent loss of bone; p < 0.05) as compared with those in the contralateral, intact control ulnae (sixteen ulnae). This finding suggested that both axial and torsional loading conditions were suitable substitutes for functional signals normally responsible for bone homeostasis. However, the intracortical response was strongly dependent on the manner in which the bone was loaded. Axial loading increased the number of intracortical pores by a factor of seven as compared with that in the controls (246 +/- 40.5 compared with 36 +/- 8.5 pores); it also increased the area lost because of porosis as compared with that in the controls (1.39 +/- 0.252 compared with 0.202 +/- 0.062 square millimeter); however, the mean size of the individual pores was similar to that in the controls (0.00565 +/- 0.0019 compared with 0.00561 +/- 0.0029 square millimeter). Conversely, torsional loading failed to increase substantially the number of pores (67 +/- 22.6 pores), the area of bone lost because of porosis (0.352 +/- 0.114 square millimeter), or the size of the pores (0.00525 +/- 0.0035 square millimeter) as compared with those in the controls. Although disuse failed to increase substantially the number of intracortical pores (59 +/- 22.4 pores), significant area (1.05 +/- 0.35 square millimeters; p < 0.05) was lost within the cortex because of a threefold increase in the mean size of each pore (0.0178 +/- 0.0126 square millimeter). It appears that bone tissue can readily differentiate between distinct components of the strain environment, with strain per se necessary to retain coupled formation and resorption, shear strain achieving this goal by maintaining the status quo, and axial strain increasing intracortical turnover but retaining coupling. While it is clear that load influences bone mass and morphology, it is also clear that specific parameters within the strain environment have distinct strategic roles in defining this architecture.

Professional expertise of occupational therapists in community practice: results of an Ontario survey

This paper presents findings of a study, The Community Practice Project, that examined the situation of occupational therapists practising in community based settings in the province of Ontario, Canada in 1992. In addition to providing a profile of the typical community based therapist, the study considered issues relating to: the principal roles in places of employment; specific job skills and areas of professional expertise utilized in the community; and how well occupational therapists; formal training prepared them for their community oriented roles and tasks. Results indicate that great opportunities exist and job satisfaction is high in community settings. Nonetheless, therapists feel inadequately prepared for the new role of consultant and its concomitant skills in a field that has re-oriented itself toward the client and is increasingly focused on health promotion and disability prevention.

Pathways into the work force: antecedents of school and work force status

OBJECTIVE

The study aim was to identify risk factors for specific pathways into the work force using data from the Ontario Child Health Study Follow-up.

METHOD

Potential predictor variables were derived from data collected in 1983 on adolescents aged 13 to 16 years. The subjects were followed up 4 years later and the school/work force outcome was determined. Bivariate and multivariate statistical analyses were used to identify variables with a strong independent association with this outcome.

RESULTS

Subjects in the work force were four times more likely than those attending school to have come from a low-income family and at least two times more likely to have a family background of low maternal education, to have failed a grade, or to have used substances heavily during early adolescence. Subjects with two or more of these risk factors were likely to be in part-time work or unemployed.

CONCLUSIONS

Preventive interventions should be targeted at children from poor families, or who fail at school, or show early onset of substance abuse and other deviant behaviors. Studies are needed to further elucidate the relationship between these risk factors and pathways into the work force and beyond.

Cow's milk versus soy-based formula in mild and moderate diarrhea: a randomized, controlled trial

We determined the efficacy of a soy-based formula compared with a cow's milk formula in infant refeeding after acute diarrhea in a randomized controlled double-blind clinical trial. Infants 2-12 months of age with diarrhea of less than one week's duration and mild or moderate dehydration admitted to a pediatric hospital or in the practice of a participating primary care pediatrician were investigated. Seventy-six patients were enrolled and 73 completed the study; 39 infants received a soy-based formula (Isomil) and 34 received a cow's milk formula (SMA). Hospitalized patients were rehydrated with an oral glucose-electrolyte solution or an iv dextrose-sodium solution. Outpatients received oral glucose-electrolyte solution. In all patients, the study formula was commenced ad libitum during the first 24 h as determined by the attending pediatrician. The primary outcome measure was duration of diarrhea, defined as time to first normal stool, when subsequent stools were normal for a 24-h period. In addition, a predetermined secondary outcome was proportion of treatment failures, defined as the need to reinstitute clear fluids because of emesis, refusal to accept study formula, need for iv fluids due to negative fluid balance or diarrhea persisting beyond 7 days after enrollment. Total duration of diarrhea was significantly longer (p = 0.03) in those receiving cow's milk (mean +/- SD 6.6 +/- 4.2 days) than in those receiving soy-based formula (4.5 +/- 3.6 days). Volume of formula intake and weight gain at 14 days were not different in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of evidence of Chlamydia pneumoniae infection in infants with acute lower respiratory tract disease

In order to determine whether there is serologic evidence of Chlamydia pneumoniae infection in young infants with acute lower respiratory tract infection, serum samples from 86 subjects aged less than 6 months were assayed for IgG and IgM antibodies to Chlamydia pneumoniae using a microimmunofluorescence method. Infants hospitalized in Toronto, Canada, were enrolled between 15 March 1991 and 15 March 1992. No patient had infection determined by the serologic results. IgG antibody was detected at low concentrations in 32 patients, with an inverse relationship between titer and chronological age. In our setting, Chlamydia pneumoniae does not appear to be an important lower respiratory pathogen in young infants.

Chromosomal translocation in T-cell leukemia line HUT 78 results in a MYC fusion transcript

Primary cultures and established cell lines derived from human T-cell leukemias were analyzed for genomic rearrangements in the region 3' of the MYC locus. A T-cell leukemia line, HUT 78, whose 3' MYC region is rearranged, carries a chromosome t(2;8) juxtaposition; i.e., a locus derived from chromosome region 2q34 is attached to the 3' end of one MYC allele. The t(2;8) rearrangement in the HUT 78 cell line results in expression of a fused transcript encompassing the MYC gene and a locus designated TCL4 (T-cell leukemia/lymphoma 4), which normally resides on chromosome 2. The steady-state level of MYC-TCL4 fusion transcripts in HUT 78 cells is significantly higher than the MYC RNA level found in several other B- and T-cell lines. The production of fused MYC-TCL4 transcripts in a leukemic cell line raises the possibility that other B- and T-cell leukemias may express MYC fusion transcripts as an integral step in their pathogenesis.

Prediction of human papilloma virus antigen in cervical squamous epithelium by koilocyte nuclear morphology and "wart scores": confirmation by immunoperoxidase

Koilocytes (balloon cells) in cervical squamous epithelium can be distinguished by their nuclear morphology as members of two populations A and B. The proposition that population A was infected with human papilloma virus (HPV) and population B was not, was examined immunohistologically. A peroxidase-antiperoxidase technique using polyclonal HPV antibody failed to support the hypothesis and showed small fractions of both populations to be infected with the virus (A = 5 of 25; B = 2 of 19). Nuclear morphology alone is thus inadequate to distinguish infected from non-infected koilocytes, or balloon cells. When a number of well established histological changes in squamous epithelia infected with HPV were examined, graded, and summated to obtain a "wart score," however, a reasonably accurate prediction of HPV infection emerged.

Temperature gradients in pigs during whole-body hyperthermia at 42 degrees C

Temperature was simultaneously measured by thermistors in multiple deep-body and peripheral sites in adult pigs heated continuously at 42 degrees C (rectal) and above for 4-24 h. During hyperthermia, the relations between different body temperatures were maintained and up to 1.0 degrees C separated temperature measurements at sites such as liver and bone marrow. These persistent temperature gradients must be borne in mind when evaluating tumor response in patients subjected to whole-body heating for disseminated cancer. Temperatures recorded by rectal, deep esophageal, or tympanic membrane sensors provided a reliable index of core temperature (including brain temperature) under equilibrium conditions at 42 degrees C, but only esophageal and tympanic sensors could safely be used to monitor the induction phase of hyperthermia and the adjustive changes in body-heat content required to stabilize core temperature during sustained hyperthermia. Pigs withstood repeated heating at 42 degrees C for 6 h, and recovered rapidly, but died after 24 h of hyperthermia. Pigs subjected to unrestrained heating died at 45 degrees C (esophagus).

Effects of ageing on the pharmacokinetics of pancuronium

The effects of age on the pharmacokinetics of pancuronium were investigated. The distribution volume of pancuronium did not appear to be age-dependent, but elimination of the drug decreased with increasing age. The clinical implications of these findings are discussed.

A pharmacodynamic model for pancuronium

It has been demonstrated that a simple two-compartment kinetic model may account for the changes in plasma concentration of pancuronium after i.v. administration. However, it can be shown that this simple model does not account satisfactory for the observed changes in muscle twitch response. By the addition of a receptor (biophase) compartment, twitch response can be reconciled with model behavior and the characteristics resemble those predicted by animal studies. The complete model is applied to the problem of total renal failure, and shows that patients with this condition are likely to be marginally resistant to small doses of pancuronium, with a normal rate of recovery. However, larger doses are likely to result in delayed recovery, the duration of effect increasing in a dose-dependent manner.

Inhalation anesthesia with methoxyflurane for guinea pig ear surgery

Anesthesia with methoxyflurane is ideal for long-term middle ear experiments on guinea pigs. This communication describes the use of a conventional pediatric anesthetic circuit that delivers a mixture of methoxyflurane and air by a face mask; it is effective, safe, and simple to use.

Pancuronium and the placental barrier

Maternal and cord levels of pancuronium were estimated using a fluorimetric method in a series of ten patients. Low concentrations of pancuronium (0-04--0-1 microng/ml) were found in all the cord samples analysed, indicating placental transfer of pancuronium.

Pharmacokinetic analysis using an electrical analogue

After i.v. administration, the distribution and elimination of many drugs may be simulated by a compartmental mathematical model. The analogue can be used to construct such models in electrical terms. When programmed with an appropriate model, the analogue can be used in a wide range of predictive studies. The application of the analogue is illustrated by analysis of serial plasma concentrations of fentanyl and pancuronium.

Pharmacokinetics of pancuronium in patients with normal and impaired renal function

Plasma concentrations of pancuronium were measured using a fluorimetric method in six patients with normal renal function and seven patients in chronic renal failure. A tow-compartment open model was used in the pharmacokinetic analysis of the data. With this model, the clearance of pancuronium was found to be reduced significantly in the patients with renal failure, and in these individuals the volume of the central (distribution) compartment was increased significantly. The clinical implications of these findings are discussed.