External Validation of the BACES Score in Canadian Patients With Nontuberculous Mycobacterial Pulmonary Disease

BACKGROUND

The clinical course of nontuberculous mycobacterial pulmonary disease (NTM-PD) can be variable and difficult to predict. Recently, the BACES score was developed as a tool to predict all-cause mortality in patients with NTM-PD. This score is calculated based on five patient characteristics (BMI, age, cavity, erythrocyte sedimentation rate, and sex), and higher scores portend worse prognosis. Although the BACES score has been validated in a cohort of South Korean patients, it has not yet been validated in other settings or ethnic groups.

RESEARCH QUESTION

How well does the BACES mortality score perform in a cohort of Canadian patients with NTM-PD?

STUDY DESIGN AND METHODS

We performed a single-center retrospective chart review. Patients who were seen between July 2003 and June 2021 were eligible for inclusion if they met guideline-based diagnostic criteria for NTM-PD and were excluded if any component of the BACES score was missing. To assess the model's discriminatory performance, we compared Kaplan-Meier curves between risk groups and calculated Harrell's C index. To assess calibration, we used a graphical calibration curve.

RESULTS

The cohort included 435 patients with a median follow-up of 5.8 years. The median age was 64 years and 74% were female. Based on the BACES scores, patients were classified into three risk groups: low, moderate, or high. Survival curves showed clear separation of the risk groups. Harrell's C index was 0.733 in the study cohort, indicating moderate to good discriminatory performance, although this was lower than the value reported in the derivation cohort (0.812). The graphical calibration curve showed a tendency of the BACES model to underpredict mortality.

INTERPRETATION

The BACES model was evaluated in a multicultural cohort of Canadian patients and demonstrated good discriminatory performance but suboptimal calibration, which may be due to population differences, the use of dichotomized variables in model construction, or both.

Disseminated Cryptococcus neoformans presenting with an isolated pleural effusion in a patient receiving temozolomide and long-term steroids

Cryptococcus neoformans is a ubiquitous environmental organism found worldwide. Infection with this organism occurs predominantly in immunocompromised hosts, including persons living with HIV or those with impaired cellular immunity. Cryptococcal pleural effusions have been described in cases with extensive pulmonary involvement. Here we present the case of a woman receiving temozolomide and steroids for glioblastoma multiforme, who developed cough and dyspnoea and was found to have an uncomplicated pleural effusion. Pleural fluid culture grew Cryptococcus neoformans with negative culture on bronchoalveolar lavage. High serum cryptococcal antigen titre of 1:64 prompted lumbar puncture which demonstrated positive cerebrospinal fluid for Cryptococcus neoformans She was treated with liposomal amphotericin B and flucytosine, followed by consolidation and maintenance therapy with fluconazole. Pleural involvement in the absence of pulmonary involvement has rarely been reported. We review pulmonary and radiographic manifestations of cryptococcal infection, when to assess for disseminated infection, and management principles.

MOP and NOP receptor interaction: Studies with a dual expression system and bivalent peptide ligands

Opioids targeting mu;μ (MOP) receptors produce analgesia in the peri-operative period and palliative care. They also produce side effects including respiratory depression, tolerance/dependence and addiction. The N/OFQ opioid receptor (NOP) also produces analgesia but is devoid of the major MOP side effects. Evidence exists for MOP-NOP interaction and mixed MOP-NOP ligands produce analgesia with reduced side effects. We have generated a HEK_MOP/NOP human expression system and used bivalent MOP-NOP and fluorescent ligands to (i) probe for receptor interaction and (ii) consequences of that interaction. We used HEK_MOP/NOP cells and two bivalent ligands; Dermorphin-N/OFQ (MOP agonist-NOP agonist; DeNO) and Dermorphin-UFP101 (MOP agonist-NOP antagonist; De101). We have determined receptor binding profiles, GTPγ[³⁵S] binding, cAMP formation and ERK1/2 activation. We have also probed MOP and NOP receptor interactions in HEK cells and hippocampal neurones using the novel MOP fluorescent ligand, Dermorphin_ATTO488 and the NOP fluorescent ligand N/OFQ_ATTO594. In HEK_MOP/NOP MOP ligands displaced NOP binding and NOP ligands displaced MOP binding. Using fluorescent probes in HEK_MOP/NOP cells we demonstrated MOP-NOP probe overlap and a FRET signal indicating co-localisation. MOP-NOP were also co-localised in hippocampal tissue. In GTPγ[³⁵S] and cAMP assays NOP stimulation shifted the response to MOP rightwards. At ERK1/2 the response to bivalent ligands generally peaked later. We provide evidence for MOP-NOP interaction in recombinant and native tissue. NOP activation reduces responsiveness of MOP activation; this was shown with conventional and bivalent ligands.

Linear body measurements and productivity of subtropical Holstein-Friesian dairy calves

OBJECTIVE

The study aimed to describe growth parameters and to quantify the association between linear body measurements as predictors of liveweight (LW) of Holstein-Friesian (HF), and HF crossbred dairy calves in Queensland. A secondary objective was to quantify the effect of disease events on LW change.

STUDY DESIGN

Longitudinal study.

METHODS

Fortnightly LW, hip height (HH), hip width (HW) and heart girth (HG) measurements were recorded from 16 male and 28 female HF calves from birth until weaning. The association between linear body measurement and the effect of a disease event on LW change were explored using linear mixed-effects modelling with random intercepts and random slopes.

RESULTS

HG was the best body measure used individually as a predictor of calf LW (R2 = 82%; P < 0.001), while the combined use of HG, HW and HH was the most accurate predictor of calf LW between birth and weaning (R2 = 90%; P < 0.001). HW, average feed intake and total feed intake were significantly affected by disease events (P < 0.05). On average, total average LW loss associated with a single pneumonia event was estimated at 14.6 kg (95% CI = 10.5 to 18.7 kg; P < 0.05).

CONCLUSIONS

Calves of this study performed at a level consistent with the previously published reports. Growth performance was significantly compromised by pneumonia. HW was found to be the least predictive individual measure, and the combined use of HH, HW and HG had the most accurate prediction of calf liveweight from birth to weaning.

The experience of medical communication in adults with acute leukemia: Impact of age and attachment security

BACKGROUND

Health care providers' (HCPs) communication with cancer patients provides both information and support. Younger patient age and greater difficulty accepting support (attachment security) have been linked to poorer communication experiences with HCPs. The present secondary data analysis examined the impact of age group and attachment security on perceived communication problems with HCPs in adults with acute leukemia (AL).

METHODS

The sample included 95 younger (age < 40 years) and 225 older (age ≥ 40 years) patients with newly diagnosed or recently relapsed AL. We assessed avoidant and anxious attachment security (reluctance to accept support and fear of its unavailability, respectively) with the modified 16-item Experiences in Close Relationships Scale. The impact of age group and attachment security on perceived communication problems, measured with the Cancer Rehabilitation Evaluation System-Medical Interaction Subscale, was assessed based on the presence and extent of communication problems.

RESULTS

Younger patients (OR = 1.79-1.82, P = .030) and those with greater avoidant (OR = 1.44, P = .001) or anxious attachment (OR = 1.38, P = .009) were more likely to report communication problems. A similar relationship was found between age (β's = -.17-.19, P = .015-.025), avoidant (β = .29, P = .013), or anxious attachment (β = .17, P = .031), and the extent of communication problems. A significant age-group × avoidant-attachment interaction (β = -.31, P = .008) suggested that more avoidant attachment was associated with more perceived communication problems in the younger but not in the older group.

CONCLUSIONS

Younger patients with AL, especially those more reluctant to seek or accept support, perceive more communication problems with their HCPs than older patients. Greater attention by HCPs to their communication with younger patients is needed.

An investigation of the relationship between race performance and superficial digital flexor tendonitis in the Thoroughbred racehorse

REASONS FOR PERFORMING STUDY

There is limited information regarding the number of races and the period for evaluation of outcome which is critical for assessment of SDF tendonitis treatments.

OBJECTIVE

To evaluate the re-injury rate and racing performance of Thoroughbred racehorses that sustain SDF tendonitis in relation to matched controls in terms of number of races post treatment and maximum racing performance ratings before and after injury.

STUDY DESIGN

Clinical records and racing histories of 401 racehorses with a first occurrence of SDF tendonitis diagnosed by ultrasonography. Controls were of the same age, sex and were horses training in the same establishment at the time of injury as the case horses and where the trainer reported that the horse had not had a previous SDF tendon injury or treatment.

RESULTS

Eighty percent of both case and control horses returned to racing after the date of injury, and the re-injury proportion within 3 years of treatment was 53%. The difference in Racing Post Rating((max)) (RPR((max))) and the Racing Post Rating in the race immediately before the treatment date was significantly smaller in case horses (mean = 9.6 lbs; range = 0-75) compared to control horses (mean = 17.0 lbs; range = 0-79). No significant decrease in RPR((max)) was noted post injury. No difference between case and control horses was found for return to racing and racing 3 times, but control horses were significantly more likely to compete 5 races post treatment date than case horses.

CONCLUSION AND CLINICAL RELEVANCE

Injury was associated with an individual's pre-injury maximum performance level and return to racing and completion of 3 races are not useful indicator of the outcome of horses with SDF tendonitis. The assessment of the outcome of horses with an SDF injury in a population of racehorses using the number of races post injury requires a minimum of 5 races post injury to be a useful indicator. Further, a re-injury proportion in a population of horses in training for 3 years post treatment.

320. THE ROLE OF FIZZY RELATED 1 IN MALE MEIOSIS

Accurate chromosome segregation during mitosis and meiosis is facilitated by a regulatory complex known as the Anaphase Promoting Cyclosome (APC), an ubiquitin ligase complex that tags proteins with ubiquitin. Subsequently targeted proteins are recognised by the 26S proteosome and degraded. In mammalian cells, two temporally regulated co-activators are required for the APC to function; fizzy and fzr1. In studies of female oocyte development fzr1 has been demonstrated to play an important role in maintaining G2 arrest during meiosis by controlling spatial levels of the cell cycle protein Cyclin B1 but the role of Fzr1 in spermatogenesis remains unknown. Germ cell specific conditional knockout fzr1mice were generated using the DDX4-Cre and flox/flox fzr1 mouse lines and initial gross morphological analysis indicated that at 7 weeks of age null mice possessed significantly smaller testes (21.81mg ± 0.23mg) when compared to heterozygote (99.86mg ± 1.58mg) and wildtype littermates (93.06mg ± 1.16mg) n = 3 P < 0.0001. Quantitative gene expression analysis confirmed almost complete absence of fzr1 transcript in testes (20-fold decrease) in comparison to wild-type. Immunoblotting and immunohistochemistry revealed no expression of Fzr1 protein in meiotic and post meiotic germ cells when compared to heterozygote and wild type littermates. Histomorphological analysis of testes tissue sections revealed Fzr1 null males exhibited spermatogenic arrest and a complete absence of round spermatids with concomitant apoptosis in the residual spermatocytes. Epididymal examination confirmed a complete lack of mature spermatozoa in the cauda epididymis of null males. In contrast, both wild type and heterozygote mice displayed normal spermatogenesis and epididymal sperm analysis indicated no distinguishable differences in seminal characteristics with normal motility, morphology and sperm-zona binding capacity. Based on these observations we hypothesise that Fzr1 plays a significant role in the establishment and maintenance of meiosis possibly through regulation of key cell cycle proteins.

Are antipsychotic drugs the right treatment for challenging behaviour in learning disability?: The place of a randomised trial

People with learning disability sometimes display challenging behaviour. This can be managed by use of antipsychotic medication or behavioural therapy or both. There is no solid evidence, however, that these therapies are safe and effective. A randomised controlled trial of antipsychotic medication has been proposed to deliver such evidence. However, this presents difficult issues in the ethics of research with learning disabled people. In particular, is a trial the most efficient and fairest way to evaluate practice in this area? This paper reviews the clinical situation, gives the rationale for the trial, and analyses the ethical arguments for and against such a trial.

Randomised trial of iodine intake and thyroid status in preterm infants

BACKGROUND

Low levels of circulating thyroid hormones have been associated with poorer general and neurodevelopmental outcome in preterm babies and it has been speculated that the association is causal. Low levels of circulating thyroid hormone have been reported after inadequate intake of iodine in preterm infants being fed milk formula.

AIM

To investigate whether increased iodine intake from supplemented preterm formula would improve thyroid hormone levels in preterm babies (this study) and hence improve neurodevelopmental status (planned subsequent study).

METHOD

A total of 121 preterm infants were entered into a randomised controlled trial of standard (68 microg/l) versus increased (272 microg/l) iodine in preterm formula.

RESULTS

The two groups were comparable at recruitment. No evidence of an effect of the intervention on thyroid hormone levels was seen up to 41 weeks after conception.

CONCLUSION

Calls for increased iodine content of preterm infant formulas are not justified by this study.

Stressors and concerns in teen asthma

Adolescents are uniquely susceptible to poor outcome with asthma because of their desire for autonomy, denial of disease, preference for immediate gain rather than prophylaxis, restricted ability to control their psychosocial and physical environment, and difficult transition to health care. Tobacco smoking as well as related drug abuse and passive exposure to tobacco is a major obstacle to managing adolescent asthma, together with atopy and psychosocial problems. Recent investigations indicate that adolescents are uniquely susceptible to tobacco industry promotions and logos because of these developmental characteristics. By understanding adolescent development, behavior and peer group impact, with its spectrum from early to late adolescence, clinicians can target their educational interventions more successfully in asthma. Health care provision for the adolescent with asthma requires a multidisciplinary team spearheaded by a primary care provider with the expert guidance of an allergist, outreach nurse, mental health worker, and social service representative. This care must be negotiated with an appropriate educational plan on the basis of NHLBI guidelines to be successful. Medications should be prescribed no more than twice a day, whenever possible, in conjunction with an action plan on the basis of peak flow readings to warn the adolescent when to use more medication and when to call the clinician. The plan should empower adolescents by recognizing their need for autonomy with self-management, enabling them to have a safe and comfortable lifestyle, and being physically and mentally at ease with their peers, family, school, and work environments.

Stressors and concerns in teen asthma

Adolescence is a time of increased stress because of intellectual, physical, and sexual maturity culminating in a desire for autonomy. Chronic asthma is perceived as a burden handicapping autonomy. This is apparent in the impairment of athletic and social activity. Furthermore, there is the requirement for inhaled medications that are perceived as hampering crucial peer identification. Nonadherence is epidemic, best resolved by empathetic rapport with the adolescent, family, and peer group while maintaining the status of a culturally and ethnically sensitive professional respected by the adolescent. The adept provider negotiates treatment plans in consultation with the adolescent with mutual respect. Treatment needs to be simple; once or twice per day, with a clear action plan acknowledging when to call the provider.

Physiological effects of thermal stress on aviators flying a UH-60 helicopter simulator

An evaluation of the physiological effects on aviators of heat stress (90 degrees F wet bulb globe temperature [WBGT]) versus a cooler condition (70 degrees F WBGT) when wearing either a MOPP0 (Mission-Oriented Protective Posture 0) uniform or a MOPP4 ensemble encumbered with a ballistic chest plate and overwater survival gear was performed at the United States Army Aeromedical Research Laboratory. The study used a repeated-measures design with 14 aviators flying 4-hour missions in a UH-60 helicopter simulator. Average crew endurance in the MOPP4-hot condition was reduced to one-third of the fully completed mission time of 309 minutes. For the hot condition, core temperature in the simulator rose 1.4 degrees F/hour when aviators wore the encumbered MOPP4 ensemble versus 0.27 degree F/hour when they wore the MOPP0 uniform. Sweating rate in the MOPP4-hot condition was 1,523 ml/hour, resulting in 2.5% dehydration, in contrast to 183 ml/hour and 0.9% dehydration in the MOPP4-cool condition. In this study, pilots flying realistic UH-60 simulator sorties rapidly incurred significant physiological heat strain when wearing an encumbered MOPP4 flight ensemble in hot cockpit conditions.

The free running athletic screening test as a screening test for exercise-induced asthma in high school

As part of a multicenter study envisioned by the American College of Allergy Sports Committee to screen for exercise-induced asthma, 303 high school students, freshman and sophomore gym classes, completed a questionnaire concerning exercise-related asthma, chronic asthma, and atopy. The study group included 124 females (41%) and 179 males (59%) with an average and median age of 15 years and a range of 13-17 years, and included 99% Caucasian and 1% nonCaucasian students, all attending the same parochial high school. After obtaining informed consent, 112 (37%) agreed to a free running test with initial challenge on an outdoor cinder track during April-June 1995. All challenges were conducted between 8:00 A.M. and noon with relative-humidity 59% and average temperature 15 degrees C. The challenge consisted of 7 minutes of continuous running on the cinder track with a doubling of pulse rate to 160/min during the run. Peak expiratory flows were taken at baseline, 0, 5, and 10 minutes postexercise. Twenty nine of 112 (26%) of the students were initially assessed as positive challenges, defined as a 15% decline in peak flow following exercise on the first challenge. However, four students self-recovered; thus 25 of 112 (22%) were qualified as true positives. Of these 25, 20 (80%) agreed to be reexercised. Fourteen of 20 (70%) were positive, yielding a prevalence rate of 14/112 (12.5%). Sixteen of these 20 (80%) were then exercised a third time using spirometry pre- and postexercise. Eight were positive, yielding a prevalence rate of 8/112 (7%). The questionnaire correlated significantly with the challenge, particularly when read by section (p = 0.000001) rather than globally positive or negative (p = 0.00008), with a specificity of 64%, sensitivity of 94%, positive predictive value of 44%, and negative predictive value of 97%. In summary, inexpensive and familiar free-running tests can be a useful screening test to confirm the questionnaire which is sensitive (94%) in ruling in, but has low specificity (64%) in ruling out, exercise-induced asthma.

Latex hypersensitivity in a horse farmer

Latex immediate hypersensitivity has been documented in 28% to 67% of spina bifida patients, 2.6%-16.9% of health care workers and at least 1% of the general population. Additionally, it has been confirmed in food-sensitive individuals sensitive to cross-reacting foods such as chestnut, avocado, banana, and passion fruits. Recently it has been observed even in low risk populations that are defined by absence of the conventional risk factors of atopy and exposure. We report the first documented case of latex allergy in a horse farmer who had the joint factors of atopy and exposure. This case exemplifies the paramount importance of screening all patients with a careful history first and appropriate testing for latex allergy when possible.

The cranial base in obstructive sleep apnea

PURPOSE

The purpose of this investigation was to determine if there are cranial base differences in adults with obstructive sleep apnea (without identifiable craniofacial abnormalities) when compared with those of adults without airway problems.

METHODS

Cephalometric analysis of the cranial base of 52 patients with documented sleep apnea were compared with 96 normal adult patients. Each of the groups was subdivided based on skeletal profiles (Class I, II, III). Cephalometric measurements included cranial base flexure angle and anterior and posterior cranial base lengths. Standard analysis of variance and Students' t test were used to determine level of significance.

RESULTS

The cranial base flexure angle in patients with documented sleep apnea was significantly more acute than that found in the nonapnea group. Patients with a skeletal Class III profile had the most acute cranial base flexure whereas those with Class II profiles had the most obtuse angles. This pattern was true for apnea and nonapnea groups. No cranial base length differences could be found in either group.

CONCLUSION

The results of this study demonstrate that there were abnormalities of the cranial base in patients with obstructive sleep apnea. Abnormalities of the cranial base seen in "nonsyndrome" obstructive sleep apnea patients are similar to those seen in patients with certain identifiable syndromes. This may suggest that sleep apnea is a reflection of a form of craniofacial syndrome.

Incidence and progress of middle ear effusion in allergy practice as detected by acoustic otoscope reflectometry

The incidence and progress of middle ear effusion (MEE) in allergy practice is not well established in prospective studies. A total of 393 patients were screened for MEE by history and physical including pneumatic otoscopy, prick and intradermal skin tests, acoustic otoscope reflectometry (AOR), impedance tympanometry (IT), and audiometry for those with established MEE. The primary diagnosis of the screened patients was intrinsic asthma in 70 or 18%, allergic rhinitis in 134 or 34%, allergic rhinitis and asthma in 80 or 21%, miscellaneous in 103 or 26%. Twenty patients were receiving immunotherapy (5%), and 89 (23%) had middle ear effusion (MEE). Among the MEE group were 52 males (58%), 37 females (42%), with an average age of 13 years, median of 8 years, and range of 6 months to 13 years. The MEE group was statistically different demographically from the initial group (P < .05) for age and history of recurrent otitis. The MEE group's primary diagnosis was similar to that of the initial group, except that there was a statistically significant difference in the number of patients on immunotherapy (P < .05) and those in the MEE group, with 11 (12%) versus 20 or 5% in the initial group. MEE resolved in 91% of cases which could be followed to resolution, with average duration of nasal steroid of 4 weeks, average duration of effusion 8 weeks, median 4 weeks, range 1 week to 6 months. Effusions in 8 patients (9%) were intractable with duration greater than 3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Peptides derived from the CDR3-homologous domain of the CD4 molecule are specific inhibitors of HIV-1 and SIV infection, virus-induced cell fusion, and postinfection viral transmission in vitro. Implications for the design of small peptide anti-HIV therapeutic agents

Peptides 12-25 amino acids in length from the V1J1 region of the CD4 molecule (residues 1-120) were synthesized as randomly derivatized, deliberately derivatized, or pure peptide products, and tested for their ability to inhibit HIV-1-induced cell fusion, HIV-1 and SIV infection of CD4-positive human cells, HIV-1 envelope glycoprotein binding to the CD4 molecule, CD4-neutralizing antibody binding to the CD4 holoreceptor, and CD4-dependent cellular immune function in the mixed lymphocyte and cytotoxic T-cell bioassays. Only peptides derived from the complementarity-determining region 3 (CDR3)-homologous domain of CD4, in particular CD4(81-92) and CD4(81-101), were effective antiviral agents. Within the CD4(81-92) series, R-group derivatization of selective amino acid residues was an absolute requirement for biological activity. The prototype compound T1C4E5-tribenzyl-K10-acetyl-TYICEVEDQKEE inhibited HIV-1-induced cell fusion at 32 microM, HIV-1 infection of CEM-SS cells at 10 microM, SIV infection of CEM-174 cells at less than 125 microM, gp120/CD4 binding at 60 microM, and postinfection cell-mediated viral transmission at 10-15 microM. Compounds of identical structure and derivatization, but of altered primary sequence, were substantially less active, or without activity, in these assays. These data indicate that the effect of amino acid derivatization of the CD4(81-92) peptide was most likely restriction of the flexible underivatized peptide backbone to a conformation closely approximating that of the CDR3-homologous gp120 binding site of the native CD4 molecule. Peptide antiviral activity was specific, as judged by lack of cytotoxicity, lack of inhibition of HTLV-1-induced cell fusion, and lack of inhibition of CD4-dependent cellular immune function in vitro. Further derivatization of the prototype compound involving the production of cyclic congeners yielded peptides with submicromolar potency to block HIV-1 infection, strengthening the hypothesis that previous peptide derivations accomplished partial restriction of the conformation of CD4(81-92) to one favorable for interaction with gp120. Concentrations of the original prototype compound T1C4E5-tribenzyl-CD4(81-92) that inhibited infection in vitro more than 50% could be achieved for several hours by intravenous infusion in primates and were well-tolerated at these levels. The peptide was not efficacious to inhibit establishment of viral infection at these doses; however, peptide treatment did lower average viral antigenemia and delay the cumulative time to morbidity relative to the control group.

Partial trisomy 9--further delineation of the phenotype

A patient with partial trisomy 9 (47,XX,+9pter----q22.1) had bilateral cleft lip and cleft palate, enophthalmos, severe micrognathia, small, apparently low-set ears, and dislocatable knees. The phenotypic findings are compared with those of other documented cases of total trisomy 9.

Synthetic CD4 peptide derivatives that inhibit HIV infection and cytopathicity

Synthetic peptide segments of the CD4 molecule were tested for their ability to inhibit infection of CD4+ cells by the human immunodeficiency virus (HIV) and to inhibit HIV-induced cell fusion. A peptide mixture composed of CD4(76-94), and synthesis side products, blocked HIV-induced cell fusion at a nominal concentration of 125 micromolar. Upon high-performance liquid chromatography, the antisyncytial activity of the peptide mixture was found not in the fraction containing the peptide CD4(76-94) itself, but in a side fraction containing derivatized peptide products generated in the automated synthesis. Derivatized deletion and substitution peptides in the region CD4(76-94) were used to demonstrate sequence specificity, a requirement for benzyl derivatization, and a core seven-residue fragment required for antisyncytial activity. A partially purified S-benzyl-CD4(83-94) peptide mixture inhibited HIV-induced cell fusion at a nominal concentration of less than or equal to 32 micromolar. Derivatized CD4 peptides blocked cell fusion induced by several HIV isolates and by the simian immunodeficiency virus, SIV, and blocked infection in vitro by four HIV-1 isolates with widely variant envelope gene sequences. Purified CD4(83-94) dibenzylated at cysteine 86 and glutamate 87 possessed antisyncytial activity at 125 micromolar. Derivatization may specifically alter the conformation of CD4 holoreceptor peptide fragments, increasing their antiviral efficacy.

Aortitis and large vessel arteritis in a newborn

Disseminated arteritis with extensive involvement of the aorta, as well as involvement of the arch vessels, coronary arteries, and pulmonary arteries, but not of the arteries within the liver, spleen, kidneys, or other organs, is unusual in a newborn. The presence of both acute and chronic inflammation with fibrosis, as well as calcification and focal ossification in the aorta, would suggest that the process had been present for some time before birth. This lesion should be described rather than designated by an eponym or included with such entities as Takayasu's disease. An additional finding of interest was widespread calcification in Bowman's capsules of numerous glomeruli.

The effects of surgical procedures on the blood supply to the femoral head

We have studied the effects of surgical procedures on the blood supply to the femoral head in adult dogs. The blood supply to normal adult canine femoral heads and osteoarthritic femoral heads was assessed by microvascular injection techniques and by measurement of the rate of blood flow by the hydrogen-washout technique. Circulation to the femoral head in the mature dog normally is dependent on retinacular vessels. Vascular anastomoses between the epiphysis and the metaphysis are generally not larger than capillary size. Reaming the femoral head does not devascularize the bone unless the retinacular vessels are disturbed. Stripping of the retinaculum, or combined reaming of the femoral head and stripping of the retinaculum, devascularized the femoral head in adult dogs with normal femoral heads. In the osteoarthritic hips, vascular anastomoses developed between the epiphysis and the metaphysis, so that stripping the retinaculum did not devascularize the femoral head. However, the rate of blood flow was decreased after combined reaming and retinacular stripping.

CLINICAL RELEVANCE

In the non-arthritic hip or in one with early arthritis, the retinacular vessels are of primary importance to circulation to the femoral head. Damage to these vessels during surgery will lead to osteonecrosis in a high percentage of patients. The formation of vascular anastomoses between the epiphysis and the metaphysis during the development of osteoarthritis may make the arthritic femoral head less vulnerable. However, care should be taken to preserve retinacular vessels, since in this study the rate of blood flow was decreased by reaming the femoral head and stripping the retinaculum.

The structural basis of rabbit VH allotypes: serologic studies on a1 H chains with defined amino acid sequence

The amino acid sequences for the VH regions of three homogeneous antibodies elicited by type III pneumococcal vaccine were determined. All three antibodies had the group a allotype a1. Two of the antibody H chains (3372, 3381) had identical amino acid sequences in all framework positions that are considered correlates of the VH allotype, whereas the third H chain (3T72) differed from these at positions 15 and 16. The a1 allotypic specificities of the three homogeneous antibodies were compared by quantitative radiobinding and inhibition assays by using both insolubilized anti-a1 antisera and allotypic antiserum fractions rendered specific for the homogeneous antibody 3374. It was found that antibodies 3374 and 3381 are allotypically indistinguishable and have in common an a1 allotypic specificity that predominates in pooled a1 IgG. The allotypic specificity of the 3T72 antibody, on the other hand, was markedly deficient to those of 3374, 3381, and the a1 IgG pool. This correlation of allotypic difference with amino acid sequence variation at position 15 and 16 of the H chain indicates the involvement of these two residues in a major a1 allotypic determinant.

Development of a highly sensitive radioimmunoassay for digoxin and its application in pediatric practice

The sensitivity of two established routine digoxin radioimmunoassay methods has been increased to enable the provision of a rapid and relatively atraumatic inpatient and outpatient service for neonates and small children, using capillary blood samples obtained by heel-prick. The methods employ 125I- or 3H-labelled digoxin, a rabbit antiserum raised against a digoxin: bovine serum albumin conjugate and only 10 or 25 microliter of plasma as the sample. The results obtained using these highly sensitive assays correlate closely with those found using conventional assays, requiring larger sample volumes. An apparent difference in sensitivity to digoxin has been demonstrated between infants and children more than 1 yr old. Thus infants appear to tolerate plateau phase plasma levels (mean value for non toxic infants 2.6 +/- 1.8 ng/ml) that in older children or adults would be associated with digoxin toxicity.

Plasma noradrenaline and renovascular hypertension in the rat

1. Plasma noradrenaline was measured in groups of rats up to 4 weeks after application of a renal artery clip. 2. When renal artery clipping was accoumpanied by contralateral nephrectomy (one-kidney model) plasma noradrenaline was significantly higher in hypertensive rats than in sham-operated control rats at 7, 14 and 28 days. 3. Plasma noradrenaline was not altered at any time examined in the two-kidney model (unilateral clip and contralateral kidney left in situ). 4. Neurogenic mechanisms mediated by the peripheral sympathetic nervous system appear to participate in the development of one-kidney renovascular hypertension, but do not play a significant role in the two-kidney model.